Lamarck’s theory
•Download as PPTX, PDF•
8 likes•11,239 views
Lamarck proposed the theory of inheritance of acquired characteristics, believing that (1) organisms evolve over time to better suit their environments, (2) organs develop and become more efficient through use or lack thereof, and (3) these acquired traits could be passed on to offspring. As an example, he suggested giraffes evolved longer necks from generations stretching to reach leaves, passing on small increases with each offspring. However, later experiments found no evidence acquired traits can be inherited.
Report
Share
Report
Share
Recommended
Modern synthetic theory of organic evolution shared by abdul qahar buneri
Modern synthetic theory of organic evolution shared by abdul qahar buneriAbdul Qahar {{Abdul Wali Khan University Mardan}} (Buner Campus)
The modern synthetic theory of evolution emerged in the mid-20th century from the work of Dobzhansky, Mayr, and Simpson. It combines Darwin's theory of natural selection with insights from genetics to explain evolution as changes in populations over generations due to genetic variations, population genetics, speciation, and different levels of evolution. The theory provides a statistical basis using population genetics concepts like genetic equilibrium, selection pressure, and genetic drift. It accepts random genetic change as a mechanism of evolution in addition to natural selection.Evolutionary forces
Evolutionary equilibrium, also known as Hardy Weinberg equilibrium, occurs when allele and genotype frequencies remain constant between generations in a population with no evolutionary forces. There are five main destabilizing forces that disrupt evolutionary equilibrium: 1) genetic drift, such as bottleneck and founder effects, which cause changes in allele frequencies by chance, 2) mutation, which introduces new alleles, 3) migration or gene flow between populations, which prevents divergence, 4) meiotic drive, where some alleles are overrepresented in gametes, and 5) natural selection, where some alleles provide a reproductive advantage. Together, these evolutionary forces ensure that Hardy Weinberg equilibrium is rarely achieved in natural populations.
Theory of evolution through mutation of Hugo de Vries
PowerPoint presentation Theory of evolution through mutation of Hugo de Vries from the website http://www.yourarticlelibrary.com/mutation/mutation-theory-mutation-theory-of-evolution-by-hugo-de-vries/12255/
I hope that this PowerPoint will help you in understanding Hugo de Vries' theory.
Darwinism
Darwinism is Charles Darwin's theory of evolution by natural selection, which he published in 1859. The theory proposes that all species of life have evolved over time from common ancestors through the natural selection of small, inherited variations that increase the individual's ability to survive and reproduce in their environment. Criticisms of Darwin's theory led to the modern synthesis of Darwinism with genetics in the 1930s and 1940s, forming the foundation of modern evolutionary theory.
Lemarkism
Jean Baptiste Lamarck proposed the first theory of evolution in 1809, suggesting that organisms acquire characteristics during their lifetime to adapt to their environment, and pass these acquired traits to their offspring. Over many generations, the accumulation of acquired characteristics leads to the emergence of new species. Lamarck's theory was later disproven when genetics showed that acquired characteristics are not heritable, but it represented the first scientific attempt to explain the evolution of life on Earth.
Hardy-Weinberg Equilibrium
This document discusses Hardy-Weinberg equilibrium, which describes the expected genotype and allele frequencies in a population that is not evolving. It will be in equilibrium if 5 assumptions are met: large population size, no migration, negligible mutations, random mating, no natural selection. The model consists of two equations to calculate expected allele and genotype frequencies. Observed frequencies in a sample California population at the EST locus match the expected frequencies, indicating the population is in equilibrium at this locus and not evolving. However, the assumptions are often violated in real populations.
Unit 3 Notes
The document discusses several key topics related to biodiversity and evolution:
- It estimates that there are 10 million species on Earth, demonstrating high biodiversity.
- It defines evolution as genetic changes in a population over generations, and describes microevolution within populations and macroevolution leading to new species.
- The main mechanisms driving microevolution are natural selection, where individuals with advantageous traits are more likely to survive and reproduce, and genetic drift.
- Speciation occurs when one species evolves into two or more reproductively isolated species, increasing biodiversity, and can happen in isolation (allopatric) or without isolation (sympatric).
Neodarwinism or synthetic theory of evolution
Neo-Darwinism is a modified version of Darwin's theory of evolution by natural selection. It incorporates genetic variation as the raw material for evolution. Genetic variation arises from sources like mutations, recombination, and chromosomal changes. Natural selection leads to differential reproduction of adaptive variants, increasing their frequency over generations. Reproductive isolation maintains distinctiveness between species. According to Neo-Darwinism, evolution occurs through the appearance of genetic variation, its spread through populations by natural selection, and reproductive isolation leading to speciation.
Recommended
Modern synthetic theory of organic evolution shared by abdul qahar buneri
Modern synthetic theory of organic evolution shared by abdul qahar buneriAbdul Qahar {{Abdul Wali Khan University Mardan}} (Buner Campus)
The modern synthetic theory of evolution emerged in the mid-20th century from the work of Dobzhansky, Mayr, and Simpson. It combines Darwin's theory of natural selection with insights from genetics to explain evolution as changes in populations over generations due to genetic variations, population genetics, speciation, and different levels of evolution. The theory provides a statistical basis using population genetics concepts like genetic equilibrium, selection pressure, and genetic drift. It accepts random genetic change as a mechanism of evolution in addition to natural selection.Evolutionary forces
Evolutionary equilibrium, also known as Hardy Weinberg equilibrium, occurs when allele and genotype frequencies remain constant between generations in a population with no evolutionary forces. There are five main destabilizing forces that disrupt evolutionary equilibrium: 1) genetic drift, such as bottleneck and founder effects, which cause changes in allele frequencies by chance, 2) mutation, which introduces new alleles, 3) migration or gene flow between populations, which prevents divergence, 4) meiotic drive, where some alleles are overrepresented in gametes, and 5) natural selection, where some alleles provide a reproductive advantage. Together, these evolutionary forces ensure that Hardy Weinberg equilibrium is rarely achieved in natural populations.
Theory of evolution through mutation of Hugo de Vries
PowerPoint presentation Theory of evolution through mutation of Hugo de Vries from the website http://www.yourarticlelibrary.com/mutation/mutation-theory-mutation-theory-of-evolution-by-hugo-de-vries/12255/
I hope that this PowerPoint will help you in understanding Hugo de Vries' theory.
Darwinism
Darwinism is Charles Darwin's theory of evolution by natural selection, which he published in 1859. The theory proposes that all species of life have evolved over time from common ancestors through the natural selection of small, inherited variations that increase the individual's ability to survive and reproduce in their environment. Criticisms of Darwin's theory led to the modern synthesis of Darwinism with genetics in the 1930s and 1940s, forming the foundation of modern evolutionary theory.
Lemarkism
Jean Baptiste Lamarck proposed the first theory of evolution in 1809, suggesting that organisms acquire characteristics during their lifetime to adapt to their environment, and pass these acquired traits to their offspring. Over many generations, the accumulation of acquired characteristics leads to the emergence of new species. Lamarck's theory was later disproven when genetics showed that acquired characteristics are not heritable, but it represented the first scientific attempt to explain the evolution of life on Earth.
Hardy-Weinberg Equilibrium
This document discusses Hardy-Weinberg equilibrium, which describes the expected genotype and allele frequencies in a population that is not evolving. It will be in equilibrium if 5 assumptions are met: large population size, no migration, negligible mutations, random mating, no natural selection. The model consists of two equations to calculate expected allele and genotype frequencies. Observed frequencies in a sample California population at the EST locus match the expected frequencies, indicating the population is in equilibrium at this locus and not evolving. However, the assumptions are often violated in real populations.
Unit 3 Notes
The document discusses several key topics related to biodiversity and evolution:
- It estimates that there are 10 million species on Earth, demonstrating high biodiversity.
- It defines evolution as genetic changes in a population over generations, and describes microevolution within populations and macroevolution leading to new species.
- The main mechanisms driving microevolution are natural selection, where individuals with advantageous traits are more likely to survive and reproduce, and genetic drift.
- Speciation occurs when one species evolves into two or more reproductively isolated species, increasing biodiversity, and can happen in isolation (allopatric) or without isolation (sympatric).
Neodarwinism or synthetic theory of evolution
Neo-Darwinism is a modified version of Darwin's theory of evolution by natural selection. It incorporates genetic variation as the raw material for evolution. Genetic variation arises from sources like mutations, recombination, and chromosomal changes. Natural selection leads to differential reproduction of adaptive variants, increasing their frequency over generations. Reproductive isolation maintains distinctiveness between species. According to Neo-Darwinism, evolution occurs through the appearance of genetic variation, its spread through populations by natural selection, and reproductive isolation leading to speciation.
Modern Synthetic Theory
The modern synthetic theory is the most widely accepted theory explaining organic evolution through genetics, molecular biology, and other modern fields of biology. It was first proposed by Dobzhansky in 1937 and further developed by Huxley, Muller, Fisher, Wright, Myer, and Stebbins. The theory explains that evolution occurs through five basic processes: gene mutation, chromosomal aberration, recombination, natural selection of adaptive characters, and reproductive isolation. Genetic drift and hybridization are also considered accessory factors in the modern synthesis theory of evolution.
Theory of evolution : Lamarck and darwin
Jean-Baptiste Lamarck proposed the theory of inheritance of acquired characters in 1809, which stated that (1) new needs arise from environmental changes, (2) organs develop through use or diminish through disuse, and (3) acquired characteristics are inherited by offspring. Charles Darwin later proposed the theory of natural selection in 1859, which explained evolution as being driven by (1) variation, (2) a struggle for existence where favorable variations help organisms survive and reproduce, and (3) the inheritance of favorable variations that allow populations to adapt to their environment over generations. Both theories attempted to explain the diversity of life and fossil evidence, though Darwin's theory of natural selection through random variations is now widely accepted.
Lamarckism
1) Lamarckism is a theory of organic evolution that proposes that complex organisms evolved from simpler organisms, and that characteristics acquired over the lifetime of organisms can be inherited by offspring.
2) According to Lamarckism, changes in the environment create new needs for organisms, which then develop new structures in response through the use and disuse of organs. Continuous use strengthens and develops organs over time, while disuse weakens and deteriorates them.
3) Lamarck proposed that acquired characteristics, such as a giraffe's long neck developed from stretching to reach leaves, could be passed on to offspring through inheritance.
Lamarckism and neolamarkism
This document discusses Lamarckism and Neo-Lamarckism. It provides examples of experiments that support Lamarck's theory that acquired characteristics can be inherited, such as stickleback fish developing bony plates in saltwater and mice developing longer limbs when raised at high temperatures. However, it also notes criticisms of Lamarckism, such as some organs like the heart not changing in size despite constant use. Neo-Lamarckism is presented as a modification that does not involve an internal drive for change and only heritable variations that affect germ cells can be passed on.
Adaptaive radiation
Adaptive radiation occurs when a single ancestral species diversifies rapidly into several new species with distinct ecological niches. This can happen when a group enters a new environment with unoccupied niches. Examples include Darwin's finches in the Galapagos, which diversified beak shapes to exploit different food sources, and mammals, which radiated into arboreal, aquatic, fossorial and other forms from a common ancestor. Adaptive radiation allows organisms to fill ecological space and drives evolutionary diversification.
Natural selection
The document summarizes Darwin's theory of natural selection. It explains the key factors of Darwinism: rapid multiplication of organisms, limited environmental resources causing competition, variation between individuals, and survival and inheritance of beneficial traits. Through this process of natural selection over generations, species gradually change and new species may form as variations accumulate. The theory helped explain the evolution of species and adaptation to the environment. It contrasts with Lamarckism in its view of inheritance and lack of internal forces driving evolution.
Mutation theory
Hugo de Vries proposed the mutation theory of evolution in 1901. He argued that evolution occurs via large, discontinuous mutations rather than the small, gradual variations proposed by Darwin. De Vries observed different plant varieties emerge suddenly in evening primrose experiments. He believed mutations provided new traits that could lead to new species forming in a single step. While the mutation theory highlighted an important source of variation, it was later shown that natural selection of mutations and gradual processes also drive evolutionary change.
Adaptive Radiations
TO FOLLOW THESE SLIDES you will learn about the adaptive radiations involve in evolution .
yo will learn about the parallel adaptations and its types
speciation role in the evolution
factors
key innvations
to imrove the article involving examples
Founder events
Adaptive plasticity
process of adaptive radiation
Factors promote adaptive radiations
Factors underlying adaptive radiations
defined by 0.S OSBORN
ecological space
geological
climatological
Islands
examplrs: 1.Darwin Finches 2.Cichlid fish genome -adaptive evolution, Stanford scientists
3.Anolis Lizards
Factors promote adaptive radiations
1.Generally speaking, adaptive radiations occur when new, unoccupied ecological niches become accessible to a founder population.
This can happen after a mass extinction during which the previous occupiers of those niches died out.
t can also happen when a colonizing species arrives at an island. (For instance the ancestor of the honeycreepers in Hawaii, or of Darwin's "finches" in the Galapagos)
Honey creeper
Change feeding habitat
At least 56 species of Hawaiian honeycreepers known to have existed, although all but 18 of them are now extinct.
Lack of competition. When a species enters an adaptive zone, it is poorly equipped to compete with species that have become adapted to the same niche.
For example, mudskippers are fish that are making a living on land, but they are marine fish and they don't have to compete against frogs and salamanders, which are restricted to fresh water. That is why we don't see freshwater mudskippers.
process of adaptive radiation
Ecological Release Colonization of species.
Taxon cycle
Habitat varying as population expand- species dispersal.
Adaptive plasticity Phenotypic plasticity(behavior change)
Property of an individual or genotype that may be adaptive, maladaptive or neutral with regard to an individual's fitness.
The particular way an individual's (or genotype's) phenotype varies across environments can be described as a reaction norm (Single genotype-phenotypic expression)
Speciation in adaptive radiation Founder events
Evolution theories
1. Lamarck proposed the theory of inheritance of acquired characteristics, which stated that traits acquired by organisms during their lifetime due to environmental factors could be passed on to offspring.
2. Examples Lamarck used included giraffes developing long necks from stretching to reach leaves and ducks developing webbed feet from swimming.
3. Darwin and Wallace later proposed the theory of natural selection, which explained evolution as occurring through heritable variations that provide individuals with an advantage in surviving and reproducing in their environment. Favored variations are passed on, while unfavored ones are selected against.
Darwinism and natural selection
Darwinism
Natural Selection
Conditions of Natural Selection
Types of Natural Selection
1. Directional Selection
2. Stabilizing Selection
3. Disruptive Selection
Darwinism and Neo Darwinism
The document summarizes Darwin's theory of evolution by natural selection. It discusses key concepts such as overproduction of offspring, the struggle for existence, variations and heredity, survival of the fittest, and the origin of species. It notes criticisms of Darwin's original theory, such as its inability to explain the origin of variations and intermediate forms. The document then outlines processes that can lead to variations, such as mutation and genetic drift. It also discusses inheritance of variations, natural selection maintaining constancy or promoting new species, and speciation occurring due to isolation.
Hardy weinberg law
It is the fundamental law of population genetics and provides the basis for studying Mendelian populations ( Mendelian population: A group of sexually inbreeding organisms living within a circumscribed area). It describes populations that are not evolving.
Mechanism of speciation
The process by which a new species develops from the existing species is known as speciation.
Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book On the Origin of Species. He also identified sexual selection as a likely mechanism, but found it problematic.
A species can be defined as one or more populations of interbreeding organisms that are reproductively isolated in nature from all other organisms.
When populations no longer interbreed, they are thought to be separate species.
There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric, peripatric, Parapatric, and sympatric.
Speciation may also be induced artificially, through animal husbandry, agriculture, or laboratory experiments.
Allopatric speciation: It is regarded as the most common type of speciation. It involves the physical separation of a species into two groups. This may occur due to climatic changes, movement of tectonic plates leading to the fragmentation of a mass of land, or eruption of a land mass, formation of waterways, or due to the presence of an impassable mountain range.
Parapatric mode of speciation: It occurs due to partial spatial isolation of populations, and is characterized by a small overlap in their ranges as well as significant gene flow amongst the populations. However, the gene flow reduces due to changes in the local conditions, and the two populations become reproductively isolated.
Sympatric mode of speciation: It involves the formation of new species due to a genetic divergence among a few members of the species inhabiting a single geographic area. Unlike the other modes of speciation, here genetic divergence does not arise due to increase in geographic distance, but occurs within the same niche.
Peripatric speciation was Proposed by Ernst Mayr. In this type of speciation, a small group of members inhabiting a peripheral region of the range undergo reproductive isolation to form a new species. Many a time, it is considered to be a variation of allopatric speciation.
Neo darwinism hassan
This document discusses the theory of Neo-Darwinism, which is a synthesis of Darwin's theory of natural selection and modern genetics. It describes key aspects of Neo-Darwinism, including genetic variation, mutations, natural selection, genetic drift, and isolation. Several scientists in the 20th century contributed to the development of the modern synthetic theory, including research on population genetics, genetics, and heredity. Examples are given of natural selection in industrial melanic moths and the development of antibiotic resistance in bacteria.
Fisher theory
1. Fisher's Fundamental Theorem on Natural Selection states that the rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time.
2. The theorem has been revised and clarified over time, but generally means that natural selection will tend to increase the fitness of organisms through changes in gene frequencies.
3. Fisher framed his argument in terms of parental expenditure, suggesting that natural selection will act to equalize the total parental expenditure between male and female offspring to maximize reproductive value.
Natural Selection and its types
Natural selection is a process whereby organisms better adapted to their environment tend to survive and produce more offspring. There are three main types of natural selection: directional selection favors one extreme of a trait, disruptive selection favors both extremes of a trait, and stabilizing selection favors intermediate forms of a trait. Examples of natural selection in action include the evolution of different beak shapes in Galapagos finches and the increase of melanism in moths due to pollution. Sexual selection is a form of natural selection resulting from competition or choice of mates.
Theories of organic evolution
The document discusses theories of organic evolution, including Darwin's theory of evolution by natural selection and Lamarck's theory of inheritance of acquired characteristics. Darwin's theory proposes that organisms evolve over generations through natural selection of inheritable traits that aid survival and reproduction. Lamarck's theory suggests that organisms can pass on traits acquired in their lifetime to offspring, such as giraffes inheriting long necks from ancestors that stretched their necks to reach leaves. Modern understanding incorporates genetics and shows how random mutations in DNA can provide variation for natural selection to act upon.
Gene pool
The gene pool refers to the total collection of genes and genetic variants within an interbreeding population. It can change over time through mechanisms like mutation, natural selection, and genetic drift in response to environmental pressures. Larger, more diverse gene pools may help populations better adapt to changing conditions, while smaller pools with less variation could hinder adaptation. Genetic variation within a population is measured by the number and frequencies of different gene alleles present.
best ever ppt on speciation by Nagesh sadili
1) The document discusses speciation in insects, including different species concepts, types of speciation, and mechanisms of speciation.
2) It describes four main species concepts: typological, nominalistic, biological, and evolutionary. The biological species concept, which defines species as groups of interbreeding natural populations reproductively isolated from other such groups, is most widely accepted.
3) Speciation occurs through the evolution of reproductive barriers between populations, including prezygotic barriers like habitat isolation and postzygotic barriers such as hybrid sterility. Disruptive selection can divide populations into distinct species.
Evolution ( Macro and Micro Evolution).pptx
Microevolution refers to small genetic changes within a population over a short time, like sparrows in different climates evolving different body sizes. Macroevolution involves genetic changes over long periods that result in new species, genera, and traits, as seen with human evolution from early hominins like Homo habilis. While microevolution can lead to speciation through natural selection over generations, some argue macroevolution requires entirely new structures and is not simply an extension of microevolution. Examples provided show most new organs evolve through modification of existing structures, not entirely novel innovations.
Theory of Evolution
Darwin proposed the theory of evolution by natural selection, with four main ideas: 1) Common descent, that all organisms are related through descent from a shared ancestor, 2) Gradualism, that new species arise gradually through accumulation of adaptations, 3) Multiplication of species, whereby gradual changes lead to diversification, and 4) Natural selection, the mechanism by which organisms better adapted to their environment are more likely to survive and produce offspring.
Darwin’s theory of evolution
Charles Darwin developed the theory of evolution by natural selection based on observations he made during a 5-year voyage on the HMS Beagle. His theory proposed that all species share a common ancestor and evolve over time through gradual processes of variation, competition for limited resources, and natural selection of beneficial traits. Key evidence came from studies of finches and tortoises on the Galapagos Islands which had adapted in different ways on different islands. Darwin's theory revolutionized scientific understanding of the diversity and relatedness of life on Earth.
More Related Content
What's hot
Modern Synthetic Theory
The modern synthetic theory is the most widely accepted theory explaining organic evolution through genetics, molecular biology, and other modern fields of biology. It was first proposed by Dobzhansky in 1937 and further developed by Huxley, Muller, Fisher, Wright, Myer, and Stebbins. The theory explains that evolution occurs through five basic processes: gene mutation, chromosomal aberration, recombination, natural selection of adaptive characters, and reproductive isolation. Genetic drift and hybridization are also considered accessory factors in the modern synthesis theory of evolution.
Theory of evolution : Lamarck and darwin
Jean-Baptiste Lamarck proposed the theory of inheritance of acquired characters in 1809, which stated that (1) new needs arise from environmental changes, (2) organs develop through use or diminish through disuse, and (3) acquired characteristics are inherited by offspring. Charles Darwin later proposed the theory of natural selection in 1859, which explained evolution as being driven by (1) variation, (2) a struggle for existence where favorable variations help organisms survive and reproduce, and (3) the inheritance of favorable variations that allow populations to adapt to their environment over generations. Both theories attempted to explain the diversity of life and fossil evidence, though Darwin's theory of natural selection through random variations is now widely accepted.
Lamarckism
1) Lamarckism is a theory of organic evolution that proposes that complex organisms evolved from simpler organisms, and that characteristics acquired over the lifetime of organisms can be inherited by offspring.
2) According to Lamarckism, changes in the environment create new needs for organisms, which then develop new structures in response through the use and disuse of organs. Continuous use strengthens and develops organs over time, while disuse weakens and deteriorates them.
3) Lamarck proposed that acquired characteristics, such as a giraffe's long neck developed from stretching to reach leaves, could be passed on to offspring through inheritance.
Lamarckism and neolamarkism
This document discusses Lamarckism and Neo-Lamarckism. It provides examples of experiments that support Lamarck's theory that acquired characteristics can be inherited, such as stickleback fish developing bony plates in saltwater and mice developing longer limbs when raised at high temperatures. However, it also notes criticisms of Lamarckism, such as some organs like the heart not changing in size despite constant use. Neo-Lamarckism is presented as a modification that does not involve an internal drive for change and only heritable variations that affect germ cells can be passed on.
Adaptaive radiation
Adaptive radiation occurs when a single ancestral species diversifies rapidly into several new species with distinct ecological niches. This can happen when a group enters a new environment with unoccupied niches. Examples include Darwin's finches in the Galapagos, which diversified beak shapes to exploit different food sources, and mammals, which radiated into arboreal, aquatic, fossorial and other forms from a common ancestor. Adaptive radiation allows organisms to fill ecological space and drives evolutionary diversification.
Natural selection
The document summarizes Darwin's theory of natural selection. It explains the key factors of Darwinism: rapid multiplication of organisms, limited environmental resources causing competition, variation between individuals, and survival and inheritance of beneficial traits. Through this process of natural selection over generations, species gradually change and new species may form as variations accumulate. The theory helped explain the evolution of species and adaptation to the environment. It contrasts with Lamarckism in its view of inheritance and lack of internal forces driving evolution.
Mutation theory
Hugo de Vries proposed the mutation theory of evolution in 1901. He argued that evolution occurs via large, discontinuous mutations rather than the small, gradual variations proposed by Darwin. De Vries observed different plant varieties emerge suddenly in evening primrose experiments. He believed mutations provided new traits that could lead to new species forming in a single step. While the mutation theory highlighted an important source of variation, it was later shown that natural selection of mutations and gradual processes also drive evolutionary change.
Adaptive Radiations
TO FOLLOW THESE SLIDES you will learn about the adaptive radiations involve in evolution .
yo will learn about the parallel adaptations and its types
speciation role in the evolution
factors
key innvations
to imrove the article involving examples
Founder events
Adaptive plasticity
process of adaptive radiation
Factors promote adaptive radiations
Factors underlying adaptive radiations
defined by 0.S OSBORN
ecological space
geological
climatological
Islands
examplrs: 1.Darwin Finches 2.Cichlid fish genome -adaptive evolution, Stanford scientists
3.Anolis Lizards
Factors promote adaptive radiations
1.Generally speaking, adaptive radiations occur when new, unoccupied ecological niches become accessible to a founder population.
This can happen after a mass extinction during which the previous occupiers of those niches died out.
t can also happen when a colonizing species arrives at an island. (For instance the ancestor of the honeycreepers in Hawaii, or of Darwin's "finches" in the Galapagos)
Honey creeper
Change feeding habitat
At least 56 species of Hawaiian honeycreepers known to have existed, although all but 18 of them are now extinct.
Lack of competition. When a species enters an adaptive zone, it is poorly equipped to compete with species that have become adapted to the same niche.
For example, mudskippers are fish that are making a living on land, but they are marine fish and they don't have to compete against frogs and salamanders, which are restricted to fresh water. That is why we don't see freshwater mudskippers.
process of adaptive radiation
Ecological Release Colonization of species.
Taxon cycle
Habitat varying as population expand- species dispersal.
Adaptive plasticity Phenotypic plasticity(behavior change)
Property of an individual or genotype that may be adaptive, maladaptive or neutral with regard to an individual's fitness.
The particular way an individual's (or genotype's) phenotype varies across environments can be described as a reaction norm (Single genotype-phenotypic expression)
Speciation in adaptive radiation Founder events
Evolution theories
1. Lamarck proposed the theory of inheritance of acquired characteristics, which stated that traits acquired by organisms during their lifetime due to environmental factors could be passed on to offspring.
2. Examples Lamarck used included giraffes developing long necks from stretching to reach leaves and ducks developing webbed feet from swimming.
3. Darwin and Wallace later proposed the theory of natural selection, which explained evolution as occurring through heritable variations that provide individuals with an advantage in surviving and reproducing in their environment. Favored variations are passed on, while unfavored ones are selected against.
Darwinism and natural selection
Darwinism
Natural Selection
Conditions of Natural Selection
Types of Natural Selection
1. Directional Selection
2. Stabilizing Selection
3. Disruptive Selection
Darwinism and Neo Darwinism
The document summarizes Darwin's theory of evolution by natural selection. It discusses key concepts such as overproduction of offspring, the struggle for existence, variations and heredity, survival of the fittest, and the origin of species. It notes criticisms of Darwin's original theory, such as its inability to explain the origin of variations and intermediate forms. The document then outlines processes that can lead to variations, such as mutation and genetic drift. It also discusses inheritance of variations, natural selection maintaining constancy or promoting new species, and speciation occurring due to isolation.
Hardy weinberg law
It is the fundamental law of population genetics and provides the basis for studying Mendelian populations ( Mendelian population: A group of sexually inbreeding organisms living within a circumscribed area). It describes populations that are not evolving.
Mechanism of speciation
The process by which a new species develops from the existing species is known as speciation.
Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book On the Origin of Species. He also identified sexual selection as a likely mechanism, but found it problematic.
A species can be defined as one or more populations of interbreeding organisms that are reproductively isolated in nature from all other organisms.
When populations no longer interbreed, they are thought to be separate species.
There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric, peripatric, Parapatric, and sympatric.
Speciation may also be induced artificially, through animal husbandry, agriculture, or laboratory experiments.
Allopatric speciation: It is regarded as the most common type of speciation. It involves the physical separation of a species into two groups. This may occur due to climatic changes, movement of tectonic plates leading to the fragmentation of a mass of land, or eruption of a land mass, formation of waterways, or due to the presence of an impassable mountain range.
Parapatric mode of speciation: It occurs due to partial spatial isolation of populations, and is characterized by a small overlap in their ranges as well as significant gene flow amongst the populations. However, the gene flow reduces due to changes in the local conditions, and the two populations become reproductively isolated.
Sympatric mode of speciation: It involves the formation of new species due to a genetic divergence among a few members of the species inhabiting a single geographic area. Unlike the other modes of speciation, here genetic divergence does not arise due to increase in geographic distance, but occurs within the same niche.
Peripatric speciation was Proposed by Ernst Mayr. In this type of speciation, a small group of members inhabiting a peripheral region of the range undergo reproductive isolation to form a new species. Many a time, it is considered to be a variation of allopatric speciation.
Neo darwinism hassan
This document discusses the theory of Neo-Darwinism, which is a synthesis of Darwin's theory of natural selection and modern genetics. It describes key aspects of Neo-Darwinism, including genetic variation, mutations, natural selection, genetic drift, and isolation. Several scientists in the 20th century contributed to the development of the modern synthetic theory, including research on population genetics, genetics, and heredity. Examples are given of natural selection in industrial melanic moths and the development of antibiotic resistance in bacteria.
Fisher theory
1. Fisher's Fundamental Theorem on Natural Selection states that the rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time.
2. The theorem has been revised and clarified over time, but generally means that natural selection will tend to increase the fitness of organisms through changes in gene frequencies.
3. Fisher framed his argument in terms of parental expenditure, suggesting that natural selection will act to equalize the total parental expenditure between male and female offspring to maximize reproductive value.
Natural Selection and its types
Natural selection is a process whereby organisms better adapted to their environment tend to survive and produce more offspring. There are three main types of natural selection: directional selection favors one extreme of a trait, disruptive selection favors both extremes of a trait, and stabilizing selection favors intermediate forms of a trait. Examples of natural selection in action include the evolution of different beak shapes in Galapagos finches and the increase of melanism in moths due to pollution. Sexual selection is a form of natural selection resulting from competition or choice of mates.
Theories of organic evolution
The document discusses theories of organic evolution, including Darwin's theory of evolution by natural selection and Lamarck's theory of inheritance of acquired characteristics. Darwin's theory proposes that organisms evolve over generations through natural selection of inheritable traits that aid survival and reproduction. Lamarck's theory suggests that organisms can pass on traits acquired in their lifetime to offspring, such as giraffes inheriting long necks from ancestors that stretched their necks to reach leaves. Modern understanding incorporates genetics and shows how random mutations in DNA can provide variation for natural selection to act upon.
Gene pool
The gene pool refers to the total collection of genes and genetic variants within an interbreeding population. It can change over time through mechanisms like mutation, natural selection, and genetic drift in response to environmental pressures. Larger, more diverse gene pools may help populations better adapt to changing conditions, while smaller pools with less variation could hinder adaptation. Genetic variation within a population is measured by the number and frequencies of different gene alleles present.
best ever ppt on speciation by Nagesh sadili
1) The document discusses speciation in insects, including different species concepts, types of speciation, and mechanisms of speciation.
2) It describes four main species concepts: typological, nominalistic, biological, and evolutionary. The biological species concept, which defines species as groups of interbreeding natural populations reproductively isolated from other such groups, is most widely accepted.
3) Speciation occurs through the evolution of reproductive barriers between populations, including prezygotic barriers like habitat isolation and postzygotic barriers such as hybrid sterility. Disruptive selection can divide populations into distinct species.
Evolution ( Macro and Micro Evolution).pptx
Microevolution refers to small genetic changes within a population over a short time, like sparrows in different climates evolving different body sizes. Macroevolution involves genetic changes over long periods that result in new species, genera, and traits, as seen with human evolution from early hominins like Homo habilis. While microevolution can lead to speciation through natural selection over generations, some argue macroevolution requires entirely new structures and is not simply an extension of microevolution. Examples provided show most new organs evolve through modification of existing structures, not entirely novel innovations.
What's hot (20)
Viewers also liked
Theory of Evolution
Darwin proposed the theory of evolution by natural selection, with four main ideas: 1) Common descent, that all organisms are related through descent from a shared ancestor, 2) Gradualism, that new species arise gradually through accumulation of adaptations, 3) Multiplication of species, whereby gradual changes lead to diversification, and 4) Natural selection, the mechanism by which organisms better adapted to their environment are more likely to survive and produce offspring.
Darwin’s theory of evolution
Charles Darwin developed the theory of evolution by natural selection based on observations he made during a 5-year voyage on the HMS Beagle. His theory proposed that all species share a common ancestor and evolve over time through gradual processes of variation, competition for limited resources, and natural selection of beneficial traits. Key evidence came from studies of finches and tortoises on the Galapagos Islands which had adapted in different ways on different islands. Darwin's theory revolutionized scientific understanding of the diversity and relatedness of life on Earth.
Darwin’s theory of evolution
Darwin proposed four main ideas about evolution: 1) Common descent - all organisms are related through descent from a common ancestor; 2) Gradualism - new species arise gradually through accumulation of small adaptations over time; 3) Multiplication of species - populations tend to increase in size, leading to new species; 4) Natural selection - individuals with traits better suited to the environment will leave more offspring, driving evolution.
Biology - Chp 15 - Darwins Theory Of Evolution - PowerPoint
- Charles Darwin developed the theory of evolution by natural selection based on observations he made during his voyage on the HMS Beagle from 1831 to 1836.
- He noticed that species varied between different locations and began to hypothesize that species evolved over time through natural selection, where individuals better suited to their environment were more likely to survive and pass on their traits.
- In his 1859 book On the Origin of Species, Darwin outlined his theory that evolution occurred gradually through natural selection acting on small inherited variations, resulting in the descent of all species from common ancestors and the diversification of life over deep time.
Introduction to Theory of Evolution
The document summarizes key concepts about evolution from biology class. It describes how Charles Darwin developed the theory of evolution through his observations on the Galapagos Islands of different finch species with specialized beaks. Darwin proposed that evolution occurs through overproduction of offspring, competition for resources, genetic variations or adaptations, and survival of the fittest. The theory helped explain how the first single-celled organisms evolved over 3 billion years into the diversity of species today through natural selection, mutation, and genetic drift acting on populations.
Charles Darwin
1) Charles Darwin was a British naturalist born in 1809 who studied medicine and divinity before joining a scientific expedition on the HMS Beagle as their geologist from 1831-1836.
2) While traveling on the Beagle, Darwin was influenced by the ideas of Charles Lyell and observed unique species of finches on the Galapagos Islands, sparking his theory of evolution by natural selection.
3) After corresponding with Alfred Russel Wallace, Darwin published On the Origin of Species in 1859, introducing his theory that organisms change over generations through a process of natural selection, survival of the fittest, and gradual speciation from common ancestors.
Lamarck
Jean-Baptiste Lamarck (1744-1829) was a French naturalist who developed one of the first coherent theories of evolution. He believed that species evolved over time in response to environmental changes and could pass on acquired traits to their offspring. While his ideas were mocked in his lifetime, Lamarck was the first to propose evolutionary mechanisms and his work influenced later scientists like Darwin.
Evolution powerpoint
This document summarizes key concepts about evolution, including that it occurs over time through natural selection, leading to diversity among and within species. It explains the mechanisms of evolution, including overpopulation, competition for resources, genetic variation, adaptation, and speciation. Adaptations like camouflage, warning coloration, and mimicry help organisms survive. Isolation of populations can also lead to speciation over time. The diversity of life on Earth is the result of evolution by natural selection.
Viewers also liked (9)
Biology - Chp 15 - Darwins Theory Of Evolution - PowerPoint
Biology - Chp 15 - Darwins Theory Of Evolution - PowerPoint
Similar to Lamarck’s theory
Jean Baptiste Lamarck's theory of inheritance of acquired characters
Jean Baptiste Lamarck's theory of inheritance of acquired charactersImmaculate Heart of Mary Seminary
Edited PowerPoint presentation of Jean Baptiste Lamarck's theory of inheritance of acquired characters
This PowerPoint presentation is collected from different websites and PowerPoint presentation Theories of evolution
Jean Baptiste de Lamarck was the first evolutionist to believe that organisms change over time through his three theories: the Theory of Need, the Theory of Use and Disuse, and the Theory of Acquired Characteristics. He believed giraffes developed longer necks to reach tall trees and passed these traits to offspring. However, Charles Darwin later suggested natural selection as the mechanism of evolution, where traits that aid survival, like longer giraffe necks, are selected for and passed on, while less fit traits die out. Darwin observed variations in beak structures among Galapagos finches related to food availability.
THEORIES OR OCCURRENCE OF EVOLUTION .pptx
Fossils are the most important source of evidence for evolution because they provide a record of how life has changed over time. Charles Darwin's theory of natural selection proposed that organisms vary individually and that favorable variations help organisms survive and reproduce, passing those traits to offspring. Over generations, this leads to evolution of species as less favorable traits diminish. Lamarck proposed that organisms could pass on traits acquired in their lifetime, but this was disproven, unlike Darwin's mechanism of natural selection and genetic inheritance of traits.
Evolution
This document discusses several key concepts and theories related to evolution:
1. It describes Lamarck's theory of evolution which proposed that acquired traits could be inherited. It notes this theory is no longer supported.
2. It summarizes Darwin's theory of evolution by natural selection, noting the key principles of overproduction, variation, adaptation, and natural selection.
3. It discusses Hugo de Vries' mutation theory which proposed evolution occurs through accumulation of mutations in genes.
4. It notes the modern synthesis combines Darwinian evolution through natural selection with Mendelian genetics.
Evolution
Evolution is the process of change over generations in a population of organisms. Popular belief prior to Darwin was that species were fixed, but some scientists proposed gradual change to fit environments. Darwin's theory of evolution by natural selection proposed that variation within populations and inheritance of traits with differential survival and reproduction could result in evolution of species over time. Modern synthesis combined Darwin's natural selection with genetics and population thinking.
Theories of evolution
The document discusses early theories of evolution, including those proposed by Jean-Baptiste Lamarck and Charles Darwin. Lamarck believed that organisms could pass on traits acquired during their lifetime to their offspring, and that evolution progressed towards greater complexity. His ideas were later disproven. Darwin's observations of finches during his voyage on the HMS Beagle, including variation between island populations, helped lead him to develop the theory of natural selection.
grade 10 Biodiversity and Evolution ppt.pptx
This document discusses evidence for evolution including fossil records, comparative anatomy, embryonic development, and biochemical analysis. It describes fossil records as preserved remains of organisms found in earth's crust, and methods for determining fossil age. Comparative anatomy is discussed in terms of homologous and analogous structures. Embryonic development shows similarities across species. Biochemical analysis compares amino acid sequences. Jean Baptiste Lamarck and Charles Darwin's theories of evolution through acquired characteristics and natural selection are presented. Natural selection results from variation and competition for limited resources.
Evolution of genetic variance-covariance structuer in animal.pptx
This document provides an overview of evolutionary morph metrics and the evolution of genetic variance and covariance structure in animals. It discusses key concepts in evolution like Lamarckism, Darwin's theory of natural selection, patterns of natural selection, and levels of evolution from microevolution to macroevolution. It also defines morph metrics as quantitative measurements and analysis of morphological traits used to study biological shape variation. Finally, it examines how the genetic variance-covariance matrix (G-matrix) evolves over time through processes like mutation, migration, selection, and drift, and how this impacts evolutionary responses to selection.
Evolutionary genetics.pdf
This document summarizes the theories of evolution proposed by Jean-Baptiste Lamarck and Charles Darwin. Lamarck proposed the theory of inheritance of acquired characteristics, suggesting that organisms can pass on traits acquired during their lifetime to their offspring. He believed giraffes evolved long necks from stretching to reach leaves. Darwin proposed the theory of evolution by natural selection, where favorable variations are preserved because they help organisms better survive and reproduce in their environment. According to Darwin, giraffes with longer necks were better able to survive because they could reach higher leaves for food. Both theories attempted to explain the diversity of life and fossil records, but Darwin's theory of natural selection became more widely accepted.
theories of evolution by Lamark and Darwin.pptx
This presentation consists of theories of mechanism of evolution defined by Lamark and Darwin that gives an idea about how evolution took place and how organisms evolved in nature. Also it gives a very good idea about natural selection and survival of the fittest. This pptx will give u an idea about the adaptation of organisms to their environment and the survival of the fittest.
Evolution and theories of evolution
1) The document discusses several theories of evolution including Lamarck's theory of inheritance of acquired characteristics, Darwin's theory of natural selection, and De Vries' mutation theory.
2) Lamarck believed that organisms could pass on traits acquired during their lifetime to their offspring, such as giraffes passing on long necks. Weismann disproved this through experiments on mice.
3) Darwin's theory of natural selection proposed that variations arise in populations and individuals with favorable traits are more likely to survive and pass those traits to offspring, leading to the emergence of new species over time.
Evolution.pptx
This document summarizes key concepts about evolution including Lamarck's theory, Darwin's theory, natural selection, and evidence of evolution. It discusses how Lamarck believed that acquired characteristics could be inherited, while Darwin proposed that gradual changes over generations through natural selection could lead to new species. The document uses examples like giraffes' long necks and Darwin's observations of finches on the Galapagos Islands to illustrate these concepts. It establishes that evolution means all life is descended from common ancestors and has diversified over billions of years through natural selection.
Early_Theories_of_Evolution2.ppt
The document discusses early theories of evolution, including Lamarck's theory of acquired characteristics and Darwin's theory of natural selection. Lamarck believed that characteristics acquired during an organism's lifetime could be inherited by offspring, while Darwin's theory of natural selection proposed that organisms better adapted to their environment are more likely to survive and pass on their traits. The document provides examples of natural selection in peppered moths and Galapagos finches and outlines the key points of Darwin's theory that variation exists within species and environmental pressures lead to the survival of the fittest.
Evolution-summary
The document discusses several historical theories of evolution, including theories of special creation, spontaneous generation, transmutation, use and disuse, and need. It provides examples of how each theory attempted to explain observed phenomena like the development of long necks in giraffes and elongated bodies in snakes. However, these early theories were unable to fully explain the diversity of life and inheritance of traits between generations. The document introduces Charles Darwin's theory of natural selection as able to explain these aspects of evolution.
Theories of evolution other than modern synthetic theory
1. The document discusses several theories of evolution other than modern synthetic theory, including Lamarckism, Darwinism, and the mutation theory.
2. Lamarckism proposed that acquired characteristics can be inherited and that use and disuse of organs leads to the formation of new species. Darwinism proposed natural selection and the survival of the fittest. The mutation theory proposed discontinuous evolution through large mutations.
3. Each theory has evidence supporting it but also has criticisms, and no single theory could fully explain the mechanisms of evolution.
Laz
The document discusses several concepts related to the theory of evolution and natural selection, including:
- Archaeopteryx fossils show evidence that some dinosaurs had feathers, indicating they were early birds.
- Zebras' stripes are thought to have evolved as camouflage to avoid detection by tsetse flies, which transmit deadly diseases. A zebra born without stripes would likely not survive long enough to pass on its genes.
- Studying shark tooth fossils reveals that ancient sharks had larger teeth on average than modern great whites, suggesting tooth size has decreased over time as energy requirements changed.
- Lamarck's theory of inheritance of acquired traits proposed that giraffes evolved long necks because
EVOLUTION NOTES.docx
Human beings have always been perplexed about the origin and evolution of life on earth. For centuries, a number of theories and hypothesis have been suggested to explain the evolutionary process.
In the previous year, in a very short time life was created by some supernatural power. Most of the religions and civilizations still believe in it, however, they do not have a scientific explanation and more a matter of faith. There has always been an attempt by the scientists and naturalists with keen observation, to explain the evolution scientifically and to look for its evidences.
The process of evolution involves a gradual change or variation in the organisms generation after generation. It means that the organisms of present-day have arisen from ancestors that were simpler in an organisation.
EVOLUTION NOTES.docx
Human beings have always been perplexed about the origin and evolution of life on earth. For centuries, a number of theories and hypothesis have been suggested to explain the evolutionary process.
In the previous year, in a very short time life was created by some supernatural power. Most of the religions and civilizations still believe in it, however, they do not have a scientific explanation and more a matter of faith. There has always been an attempt by the scientists and naturalists with keen observation, to explain the evolution scientifically and to look for its evidences.
The process of evolution involves a gradual change or variation in the organisms generation after generation. It means that the organisms of present-day have arisen from ancestors that were simpler in an organisation.
Theory of inheritance of acquired characters 1
1. Lamarckism is an evolutionary theory proposed by Jean-Baptiste Lamarck in 1809 that acquired traits could be inherited.
2. It had four main points: new needs arise from environmental changes, use and disuse of organs changes their development, acquired traits are inherited, and gradual accumulation of traits leads to new species.
3. While it was influential, Lamarckism was later disproven and replaced by modern evolutionary synthesis combining genetics and natural selection. Neo-Lamarckism revived some ideas incorporating new genetic findings.
History of evolutionery thought
I AM HAFIZ MUHAMMAD WASEEM from mailsi vehari
BSc from science college Multan
MSC university of education Lahore
i love Pakistan and my teachers
Similar to Lamarck’s theory (20)
Jean Baptiste Lamarck's theory of inheritance of acquired characters
Jean Baptiste Lamarck's theory of inheritance of acquired characters
Evolution of genetic variance-covariance structuer in animal.pptx
Evolution of genetic variance-covariance structuer in animal.pptx
Theories of evolution other than modern synthetic theory
Theories of evolution other than modern synthetic theory
Lamarck’s theory
- 1. LAMARCK’S THEORY Larmarck (1744-1829) was a Frence biologist who proposed the theory of the inheritance
- 2. a) Organisms tend to increase in size and complexity with time b) Changes in environment made special demands on organisms. Formation of new organ in the body is the results of a specific need felt by the animal c) The extend of the development of organs and their efficiency is proportional to their use and disuse of the organs. d) The phenotypic characteristic acquired by the parents during their lifetime can be transmitted through reproduction to the offspring.
- 3. Lamarck’s most famous illustration was using the giraffe as an example a) The long neck of the giraffe has evolved as a result of generations of giraffes stretching their necks to feed on the leaves of tall trees due to food shortage b) Each generation has transmitted to its offspring a small increase in length caused by continual stretching c) The modern giraffe thus has a very long neck due to inheritance of the acquired characteristic
- 4. However, despite many experiments carried out, no evidence has been found to support Lamarck’s theory that acquired characteristics can be inherited.