social selection
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Sexual selection leads to the evolution of traits that enhance mating success but do not necessarily help survival. These traits can include elaborate ornamentation that requires significant energy or reduces mobility. Darwin proposed sexual selection to explain the evolution of such extravagant but potentially detrimental traits seen in male peacocks and other species. Sexual selection operates through either intersexual selection, where female mate choice shapes male traits, or intrasexual selection, such as male-male combat over mates. Elaborate male traits may have evolved because they honestly signal genetic quality to females, since only males in good condition can afford the costs of such ornamentation.
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Sexual Selection
Sexual selection is a form of natural selection where animals compete to mate. There are two kinds: male competition, where males compete for territory and females, and female selection, where females choose their mates based on favorable characteristics, helping pass on those traits to future generations.
Sexual selection theory
Darwin's sexual selection theory argues that males compete for females through mechanisms like intra-sexual competition between males or inter-sexual choice by females, resulting in the development of secondary sexual characteristics in males like antlers, songs, or colorful feathers. Examples include the vocal cords in frogs, antlers in deer, songs of male birds, and the colorful feathers of peacocks. However, the theory was criticized for not fully explaining sexual dimorphism and for assuming behaviors like promiscuity that could prevent sexual selection from occurring.
Sexual Selection
Sexual selection occurs through male competition and female choice. It leads to the evolution of extreme traits in males that give them an advantage in attracting mates but may reduce survival. Sexual dimorphism arises when males and females of a species differ in traits, often with males developing more ornamented characteristics. Runaway selection can cause traits to evolve that do not improve quality but instead fulfill female preferences, like long bright tails in some species. Sexual selection drives evolution and speciation.
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Sexual Selection
Sexual selection is a form of natural selection where animals compete to mate. There are two kinds: male competition, where males compete for territory and females, and female selection, where females choose their mates based on favorable characteristics, helping pass on those traits to future generations.
Sexual selection theory
Darwin's sexual selection theory argues that males compete for females through mechanisms like intra-sexual competition between males or inter-sexual choice by females, resulting in the development of secondary sexual characteristics in males like antlers, songs, or colorful feathers. Examples include the vocal cords in frogs, antlers in deer, songs of male birds, and the colorful feathers of peacocks. However, the theory was criticized for not fully explaining sexual dimorphism and for assuming behaviors like promiscuity that could prevent sexual selection from occurring.
Sexual Selection
Sexual selection occurs through male competition and female choice. It leads to the evolution of extreme traits in males that give them an advantage in attracting mates but may reduce survival. Sexual dimorphism arises when males and females of a species differ in traits, often with males developing more ornamented characteristics. Runaway selection can cause traits to evolve that do not improve quality but instead fulfill female preferences, like long bright tails in some species. Sexual selection drives evolution and speciation.
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Sexual selection
This document discusses evolutionary theories around sexual selection and relationships. It explains that sexual selection occurs through intrasexual competition between males to attract females, and intersexual selection where females choose their mates. Research by Buss (1989) found cross-cultural differences in mate preferences, with females prioritizing resources and males prioritizing youth and attractiveness. Studies also show females' preferences change across their menstrual cycle and they favor more masculine traits when fertile. However, critics argue these theories are reductionist and deterministic by not accounting for free will or environmental influences on relationships.
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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.
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2) There are two main types of sexual selection: intrasexual selection, where males compete with each other for access to females; and intersexual selection, where females choose their mates.
3) Examples of traits that evolve due to sexual selection include weaponry used in combat between males, ornamentation used in displays to attract females, and gift-giving behaviors that benefit feeding females.
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1. Microevolution is changes in a species' genome or gene pool over a short period of time due to alterations in successfully reproducing individuals.
2. Hardy-Weinberg equilibrium describes how allele and genotype frequencies remain stable in a population not experiencing evolutionary pressures.
3. Five factors can disrupt Hardy-Weinberg equilibrium and drive microevolution: mutation, immigration, genetic drift, non-random mating, and natural selection.
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Sexual selection leads to the evolution of elaborate traits in males through female mate choice and male-male competition. These traits are often costly and seem to reduce survival. Darwin proposed sexual selection to explain the evolution of such traits. Modern theories propose that females may choose males with handicapping traits as they honestly signal genetic quality, with only high-quality males able to bear the costs. Studies support this, finding traits like peacock tails are costly and indicate parasite resistance which benefits offspring.
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When males only contribution to offspring is their sperm, females .pdf
When males\' only contribution to offspring is their sperm, females are particularly choosy. With
this high level of female choice, sexual ornaments are seen in males, where the ornaments reflect
the male\'s social status. Two hypotheses have been proposed to conceptualize the genetic
benefits from female mate choice.
First, the good genes hypothesis suggests that female choice is for higher genetic quality and that
this preference is favored because it increases fitness of the offspring. This includes Zahavi\'s
handicap hypothesis and Hamilton and Zuk\'s host and parasite arms race. Zahavi\'s handicap
hypothesis was proposed within the context of looking at elaborate male sexual displays. He
suggested that females favor ornamented traits because they are handicaps and are indicators of
the male\'s genetic quality. Since these ornamented traits are hazards, the male\'s survival must
be indicative of his high genetic quality in other areas. In this way, the degree that a male
expresses his sexual display indicates to the female his genetic quality. Zuk and Hamilton
proposed a hypothesis after observing disease as a powerful selective pressure on a rabbit
population. They suggested that sexual displays were indicators of resistance of disease on a
genetic level.
Such \'choosiness\' from the female individuals can be seen in wasp species too, especially
among Polistes dominula wasps. The females tend to prefer males with smaller, more elliptically
shaped spots than those with larger and more irregularly shaped spots. Those males would have
reproductive superiority over males with irregular spots.
Fisher\'s hypothesis of runaway sexual selection suggests that female preference is genetically
correlated with male traits and that the preference co-evolves with the evolution of that trait, thus
the preference is under indirect selection. Fisher suggests that female preference began because
the trait indicated the male’s quality. The female preference spread, so that the females’ offspring
now benefited from the higher quality from specific trait but also greater attractiveness to mates.
Eventually, the trait will only represent attractiveness to mates and no longer represent increased
survival.
An example of mate choice by genes is seen in the cichlid fish Tropheus moorii where males
provide no parental care. An experiment found that a female T. moorii is more likely to choose a
mate with the same color morph as her own. In another experiment, females have been shown to
share preferences for the same males when given two to choose from, meaning some males get
to reproduce more often than others
Solution
When males\' only contribution to offspring is their sperm, females are particularly choosy. With
this high level of female choice, sexual ornaments are seen in males, where the ornaments reflect
the male\'s social status. Two hypotheses have been proposed to conceptualize the genetic
benefits from female mate choice.
First, the good genes hypothesis.
In regards to the findings of Darwin on the intellectual differences.pdf
In regards to the findings of Darwin on the intellectual differences between men and women, he
based his complete findings entirely on the basis of a consideration of the long-continued action
of natural and sexual selection. He never took into consideration other factors. Write a 1-2 page
essay that addresses the following:
Why do you think Darwin never took into consideration the environment, social roles, influence
of culture, and the few opportunities that existed in the late 1870s for women as well as
historically for both men and women?
How do you think the findings of Darwin, in regards to women being of inferior intelligence,
would have changed if he had taken into consideration all the above factors as well as natural
and sexual selection? What would the major differences have been?
Solution
According to Darwin theory of natural selection, sexual selection is the phenomenon that drives
the evolution of life. The findings of Darwin on the intellectual differences are between men and
women depict his complete findings entirely based on a consideration of the long-continued
action of natural and sexual selection. Darwin never took into consideration the environment,
social roles, influence of culture, and the few opportunities that existed in the late 1870s for
women as well as historically for both men and women because these factors have no meticulous
effects on the \"human intellectual differences\" and gender differences. Reproductive capability
tasks plays an important stronger role to produce the progeny with strong survival rate of the
fittest is crucial in the natural selection, where human progeny often produce higher intellectual
abilities. The evolution of these offspring with higher fitness to survive in the environment with
intellectual differences between men and women, based on a consideration of the long-continued
action of natural and sexual selection (women for men with high fitness) is done through natural
selection. Therefore the resultant offspring will gain \"higher intellectual ability & high
reproductive fitness\" and genomic feature to eliminate deleterious alleles (induced by mutations)
via natural selection. Those species, which can withstand and sustain to this environment, those
will survive for a period by getting nurture from the nature. Natural selection is always occurs in
a population if there are genetic variation for a trait in that population followed by heritability of
that specific trait to the offspring as an evolutionary adaptation. Mutations also induce natural
selection and evolution of new traits
According to the findings of Darwin, in regards to women being of inferior intelligence, it would
have not changed if he had taken into consideration of the environment, social roles, influence of
culture, because “men always trying face higher “selection pressure”. Men always try to prove
physically & emotionally and intellectually higher ability or superior than other men to compete
for women as a r.
Adaptive evolution as caused by natural selection (continuation)
This document discusses different types of sexual selection: intrasexual selection where individuals of one sex compete for mates of the opposite sex, intersexual selection where one sex (usually females) chooses their mates based on traits of the other sex, and balancing selection which maintains multiple phenotypes in a population through heterozygote advantage or frequency-dependent selection. Sexual selection is a form of natural selection where certain inherited traits increase an individual's chances of obtaining a mate over others.
Sc2220 Lecture 3 2009
The document discusses the relationship between biology and gender. It argues that while human sexual biology influences gender, it does not determine gender, which is a social and cultural construct. Gender is based on cultural interpretations of human heterosexual reproduction and the ways societies organize around sexual reproduction. The document also cautions against oversimplifying biological differences and averages, noting there is significant overlap between males and females.
Heridity and Evolution - Biology Class 10 CBSE
This Powerpoint Presentation is on the chapter Heredity and Evolution from class 10 Biology in CBSE Board. The contents of the presentation are from the NCERT science textbook for class 10 and Lakhmir Singh Biology Handbook Class 10.
Day 11 oct 14th chapter 7 and 8
This document provides an overview of chapters 7 and 8 from a biology textbook. It discusses key topics like Mendelian inheritance, phenotypes and genotypes, probability in genetics, polygenic traits, sex-linked traits, evolution through natural selection, and evidence that supports evolution such as experiments on fruit flies and fossil records. The document uses bullet points, diagrams, and questions to highlight important concepts and terms from the chapters.
Funky Pigeons - Lesson 1 Artificial Selection and Genetics
Lesson 1 of an A Level teaching resource, produced in conjunction with the Charles Darwin Trust, that uses Darwin's work on pigeon breeding and the work of contemporary scientists to explore genetics and evolution.
This first lesson covers the topics of artificial selection and genetics.
The accompanying teacher's notes can be found on our website at www.linnean.org/funkypigeons
Sc2220 lecture 2 2012
This document discusses a lecture on human sex and sexuality. It begins by covering key facts about sexual reproduction, including how it creates more variety than asexual reproduction and allows for faster evolution. It then discusses different types of sexual reproduction in species, including sequential hermaphrodites and simultaneous hermaphrodites. The document emphasizes that biology does not determine gender, as gender is a social and cultural construct, and different cultures interpret human biology in various ways. It also notes that biological sex exists on multiple levels and is not strictly binary, as some individuals are intersex.
Evolution and sex
Presentación en inglés para trabajar la interacción entre la reproducción sexual y la evolución de las especies.
Evolution or change over time occurs through the processes of natura.docx
Evolution or change over time occurs through the processes of natural and sexual selection. In response to problems in our environment, we adapt both physically and psychologically to ensure our survival and reproduction. Sexual selection theory describes how evolution has shaped us to provide a mating advantage rather than just a survival advantage and occurs through two distinct pathways: intrasexual competition and intersexual selection. Gene selection theory, the modern explanation behind evolutionary biology, occurs through the desire for gene replication. Evolutionary psychology connects evolutionary principles with modern psychology and focuses primarily on psychological adaptations: changes in the way we think in order to improve our survival. Two major evolutionary psychological theories are described: Sexual strategies theory describes the psychology of human mating strategies and the ways in which women and men differ in those strategies. Error management theory describes the evolution of biases in the way we think about everything. Learning Objectives • Learn what “evolution” means. • Define the primary mechanisms by which evolution takes place. • Identify the two major classes of adaptations. • Define sexual selection and its two primary processes. • Define gene selection theory. • Understand psychological adaptations. • Identify the core premises of sexual strategies theory. • Identify the core premises of error management theory, and provide two empirical examples of adaptive cognitive biases. Introduction If you have ever been on a first date, you’re probably familiar with the anxiety of trying to figure out what clothes to wear or what perfume or cologne to put on. In fact, you may even consider flossing your teeth for the first time all year. When considering why you put in all this work, you probably recognize that you’re doing it to impress the other person. But how did you learn these particular behaviors? Where did you get the idea that a first date should be at a nice restaurant or someplace unique? It is possible that we have been taught these behaviors by observing others. It is also possible, however, that these behaviors— the fancy clothes, the expensive restaurant —are biologically programmed into us. That is, just as peacocks display their feathers to show how attractive they are, or some lizards do push-ups to show how strong they are, when we style our hair or bring a gift to a date, we’re trying to communicate to the other person: “Hey, I’m a good mate! Choose me! Choose me!" However, we all know that our ancestors hundreds of thousands of years ago weren’t driving sports cars or wearing designer clothes to attract mates. So how could someone ever say that such behaviors are “biologically programmed” into us? Well, even though our ancestors might not have been doing these specific actions, these behaviors are the result of the same driving force: the powerful influence of evolution. Yes, evolution—certain trait.
Evolving for girls one welcome
A feminist viewpoint of evolutionary psychology: asks whether the study of mate choice could do with more female voices and ideas. The tone is relatively lighthearted, and intended to encourage debate in evolutionary psychology
Lec 12 Sexual Strategies
The document discusses sexual strategies in animals, including intraselection (competition between males) and interselection (female mate choice). Both can occur simultaneously, as in peacocks where male plumage evolved through intraselection but females select mates based on plumage. More recently, competition between sexes and strategies that trade off male and female fitness have been studied. Sexual strategies aim to find mates and maximize reproductive success.
Sex determination and sexlinkedinheritance
This document defines key concepts and terminology related to genetics and sexual reproduction. It discusses:
- Mechanisms of sex determination including chromosomal (XX/XY, XX/XO, ZW/ZZ), genetic, hormonal, and environmental determination.
- Sexual differentiation in mammals is controlled by the SRY gene on the Y chromosome, which induces testes formation. Secondary sex characteristics are hormonally controlled.
- In humans, the presence of the SRY gene determines maleness, while its absence results in development of ovaries and female phenotype. Abnormal sex chromosome numbers can result in conditions like Turner syndrome.
Sex determination and sexlinkedinheritance
This document defines key concepts and terminology related to genetics and sexual reproduction. It discusses:
- Mechanisms of sex determination including chromosomal (XX/XY, XX/XO, ZW/ZZ), genetic, hormonal, and environmental determination.
- Sexual differentiation in mammals is controlled by the SRY gene on the Y chromosome, which induces testes formation. Secondary sex characteristics are controlled by sex hormones.
- In humans, the SRY gene is the testis-determining factor located on the Y chromosome. Its presence leads to testes development and a male phenotype, while its absence results in ovary development and a female phenotype.
010_ESI-ppt (1).ppt
This document summarizes a presentation on sexual selection given by Dr. Michael Ryan. It discusses how sexual selection, driven by both male competition and female choice, leads to the evolution of exaggerated secondary sexual characteristics in males. It provides examples of traits that evolve due to male competition, such as weapons for fighting other males. It also discusses mechanisms of female choice, including preferences for traits that offer direct benefits like resources, preferences for traits that indicate genetic quality like health, and cases where preferences evolve through runaway selection or sensory biases. The presentation used many examples from studies of animals like frogs, birds, insects and humans to illustrate these concepts.
Similar to social selection (20)
Darwin sexual selction, pangensis and artificial theory
Darwin sexual selction, pangensis and artificial theory
When males only contribution to offspring is their sperm, females .pdf
When males only contribution to offspring is their sperm, females .pdf
In regards to the findings of Darwin on the intellectual differences.pdf
In regards to the findings of Darwin on the intellectual differences.pdf
Adaptive evolution as caused by natural selection (continuation)
Adaptive evolution as caused by natural selection (continuation)
Funky Pigeons - Lesson 1 Artificial Selection and Genetics
Funky Pigeons - Lesson 1 Artificial Selection and Genetics
Evolution or change over time occurs through the processes of natura.docx
Evolution or change over time occurs through the processes of natura.docx
More from Aftab Badshah
Economic Crisis in SriLanka.pptx
This presentation elaborates the economic crisis in Sri Lanka. It explains the causes of economic instability in Sri Lanka and the factors worsening it. Such miserable economic situation is presenting valuable lessons for other sister asian countries to counter their economic instability. Pakistan, a sister country of Sri Lanka is facing severe political and economic instability these days. Pakistan is learning from the Sri Lankan economic situation and tending to improve its economy but the extreme political instability is hurdling and exacerbating the economic crisis. However, policies are underway to counter the economic crisis and more probably Pakistan will escape the Sri Lankan experience.
Classification of cat
1. The domestic cat is a small carnivorous mammal that is found globally and primarily lives in areas of human habitation.
2. Domestic cats come in over 100 breeds but generally have a similar body shape, weighing between 4-5 kg and measuring around 76 cm long.
3. Cats are polygynandrous, meaning both males and females can mate with multiple partners, and gestation typically lasts 60-67 days resulting in litters of kittens that are dependent on their mother for care.
Zahavi handicapp theory
The handicap principle proposes that females prefer males with handicaps (mating characters that reduce survival chances) because handicaps are indicators of heritable viability. According to the principle, honest signals of quality must be costly to produce so that low-quality individuals cannot fake them. Examples of honest signals include a peacock's tail, which is eye-catching but heavy, and a gazelle's stotting behavior before fleeing from predators, which requires energy but signals the gazelle's strength. The principle suggests signals of quality effectively lower an individual's fitness but are affordable only by those of high biological fitness.
What is evolution
1) The document discusses factors that can initiate microevolutionary changes by altering gene frequencies in populations. These include mutation, gene flow, natural selection, non-random mating, and genetic drift.
2) Five conditions must be met for a population to maintain Hardy-Weinberg equilibrium: no mutation, random mating, no natural selection, large population size, and no gene flow. Deviations from any of these conditions can lead to evolutionary changes by changing allele and genotype frequencies over time.
3) Specific factors that can drive evolutionary changes include mutation, which introduces new variants; gene flow through migration; natural selection favoring certain genotypes; non-random mating patterns; and genetic drift through random processes in small populations
The theory of endosymbiosis says that eukaryote cells have evolved from a sym...
The document discusses evidence that supports the theory of endosymbiosis, which proposes that eukaryotic cells evolved from a symbiotic relationship between prokaryotes. Specifically, it argues that mitochondria and chloroplasts in eukaryotic cells evolved from prokaryotes. It provides several lines of molecular evidence for endosymbiosis, including that mitochondria and chloroplasts divide via binary fission like bacteria, have double-layered membranes similar to bacteria, and have circular DNA like prokaryotes. Phylogenetic studies also link mitochondrial DNA closely to alpha-proteobacteria, providing support for common descent.
Special creation theory
The document discusses several historical theories about the origins of life:
1) Special creation theory proposes that all life was supernaturally created by God within a short period.
2) Spontaneous generation theory proposed that life could arise spontaneously from non-living matter, an idea that was disproven by experiments in the 17th-19th centuries.
3) Panspermia theory suggests that life originated elsewhere in the universe and was seeded on Earth via meteors or cosmic dust, but this does not fully explain the first origins of life.
Selection pressure
Selection pressure refers to factors in an organism's environment that give certain variations an advantage, pushing evolution in a direction. Random mutations occur during reproduction, and favorable mutations that increase survival and reproduction will become more common through natural selection over generations. A selection pressure can be anything consistent that impacts survival and reproduction rates, like availability of resources, presence of predators, or competition. Selection operates at the individual level, favoring traits that increase individual fitness even if they harm the species as a whole.
Rats
Rats are medium-sized rodents that are commonly distinguished from mice by their larger size. The best known rat species are the black rat and brown rat, which originated in Asia. Rats can carry diseases and have caused epidemics like the Black Death. While some rats are considered pests, others are kept as pets or used in scientific research due to their intelligence and ability to learn. Rat meat is also consumed as a food in some cultures.
Rabbits
Rabbits are small mammals found worldwide in habitats like meadows, woods, and grasslands. There are over 50 rabbit species, including European rabbits known for living in underground burrows. Rabbits have powerful back legs for hopping, large ears for detecting predators, and eat plant matter through a digestive process of excreting two types of feces - one which is immediately reingested to further extract nutrients.
Pap.macroevolution
Macroevolution examines evolution over long time periods of thousands to millions of years. It studies changes above the species level, including the emergence of new species through speciation and loss of species through extinction. Key areas of study in macroevolution include building phylogenetic trees to demonstrate evolutionary relationships between extinct and modern species based on morphological comparisons, and using molecular analysis to help validate these relationships when possible. Mass extinctions that eliminate large percentages of species are also investigated to better understand causes and patterns of extinction and subsequent radiations as new species evolve to fill open niches.
Paleontological evidence of evolution
1. Paleontology provides key evidence for evolution through the fossil record by showing forms of ancient life that are no longer present today. The fossil record spans over 4 billion years and shows how life has changed over time.
2. Early fossil discoveries in the 17th and 19th centuries, such as shark teeth and Iguanodon teeth, provided evidence that fossils represented ancient life forms.
3. Fossils form through various processes like rapid sedimentation, mineral replacement, or freezing. They can be preserved as molds, casts, or even intact remains, providing a record of prehistoric life.
Mimicry
Batesian mimicry involves harmless animals mimicking the warning colors or patterns of dangerous species to deter predators through learned avoidance. This type of mimicry is common among insects and some snakes. Henry Walter Bates first discovered this phenomenon in the Amazon and published examples, naming the concept after himself. Mullerian mimicry occurs when two actually dangerous species evolve to resemble each other, providing mutual protection against predators through stronger association of their shared warning signals with the threat of harm. Fritz Muller first proposed this concept in 1878 to explain why harmful species also converged through mimicry.
Microevolution
1. The document discusses different levels of evolution including microevolution (changes within populations), macroevolution (changes between species and higher taxa), and megaevolution (really large-scale evolution like changes between phyla).
2. It describes the hypothesis of punctuated equilibria proposed by Gould and Eldredge, which argues that most evolutionary changes occur rapidly during speciation events separated by long periods of stasis, rather than through gradual accumulation of changes.
3. Examples of macroevolutionary trends and principles are discussed, including adaptive radiation and the evolution of the horse family from small browsing ancestors to modern grazing horses.
Macroevolution
This document summarizes key concepts in macroevolution, including how macroevolutionary changes occur through both gradualism and punctuated equilibrium. It discusses evidence from fossils and comparisons between living organisms. It also covers plate tectonics, morphological divergence and convergence, developmental patterns, comparative biochemistry, molecular clocks, and taxonomy.
Genetic drift
Genetic drift refers to changes in allele frequencies in a population due to random fluctuations. Over many generations, genetic drift usually results in the loss or fixation of an allele. The rate of genetic drift depends on population size, with smaller populations experiencing greater drift due to chance fluctuations. Genetic drift can lead to loss of genetic variation and influence how populations diverge genetically over time.
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.
Extinction
1) Macroevolution describes large-scale evolutionary events such as speciation, extinction, and major trends seen in the fossil record over long periods of time.
2) Stephen Jay Gould recognized three tiers of evolutionary timescales: population genetics (tens to thousands of years), rates of speciation and extinction (millions of years), and major extinction events (tens to hundreds of millions of years).
3) Differential rates of speciation and extinction among lineages over geological time, known as species selection, represents an expansion of Darwin's theory of natural selection and helps explain macroevolutionary patterns seen in the fossil record.
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.
Evidences from comparative embryology
This document discusses evidence for evolution from comparative embryology. It notes that more complex organisms share many initial developmental steps with more primitive forms, as Darwinian evolution suggests they elaborated on existing developmental patterns. Comparative embryology studies reveal that all multicellular animals start as a single zygote and share fundamental developmental processes like gastrulation and the formation of germ layers, despite some differences. Recapitulation, where embryos of higher animals resemble embryos of lower forms, provides further evidence. Genetic factors explain recapitulation, as organisms retain genes regulating early development from ancestral forms.
More from Aftab Badshah (20)
The theory of endosymbiosis says that eukaryote cells have evolved from a sym...
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ANAMOLOUS SECONDARY GROWTH IN DICOT ROOTS.pptx
Abnormal or anomalous secondary growth in plants. It defines secondary growth as an increase in plant girth due to vascular cambium or cork cambium. Anomalous secondary growth does not follow the normal pattern of a single vascular cambium producing xylem internally and phloem externally.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
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. The X-ray sources exhibit a highly concentrated spatial distribution,
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The binding of cosmological structures by massless topological defects
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
3D Hybrid PIC simulation of the plasma expansion (ISSS-14)
3D Particle-In-Cell (PIC) algorithm,
Plasma expansion in the dipole magnetic field.
ESR spectroscopy in liquid food and beverages.pptx
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Phenomics assisted breeding in crop improvement
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
Bob Reedy - Nitrate in Texas Groundwater.pdf
Presented at June 6-7 Texas Alliance of Groundwater Districts Business Meeting
如何办理(uvic毕业证书)维多利亚大学毕业证本科学位证书原版一模一样
原版纸张【微信：741003700 】【(uvic毕业证书)维多利亚大学毕业证】【微信：741003700 】学位证，留信认证（真实可查，永久存档）offer、雅思、外壳等材料/诚信可靠,可直接看成品样本，帮您解决无法毕业带来的各种难题！外壳，原版制作，诚信可靠，可直接看成品样本。行业标杆！精益求精，诚心合作，真诚制作！多年品质 ,按需精细制作，24小时接单,全套进口原装设备。十五年致力于帮助留学生解决难题，包您满意。
本公司拥有海外各大学样板无数，能完美还原海外各大学 Bachelor Diploma degree, Master Degree Diploma
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留信网认证的作用:
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4:这个认证书并且可以归档倒地方
5:凡事获得留信网入网的信息将会逐步更新到个人身份内，将在公安局网内查询个人身份证信息后，同步读取人才网入库信息
6:个人职称评审加20分
7:个人信誉贷款加10分
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本公司拥有海外各大学样板无数，能完美还原海外各大学 Bachelor Diploma degree, Master Degree Diploma
1:1完美还原海外各大学毕业材料上的工艺：水印，阴影底纹，钢印LOGO烫金烫银，LOGO烫金烫银复合重叠。文字图案浮雕、激光镭射、紫外荧光、温感、复印防伪等防伪工艺。材料咨询办理、认证咨询办理请加学历顾问Q/微741003700
留信网认证的作用:
1:该专业认证可证明留学生真实身份
2:同时对留学生所学专业登记给予评定
3:国家专业人才认证中心颁发入库证书
4:这个认证书并且可以归档倒地方
5:凡事获得留信网入网的信息将会逐步更新到个人身份内，将在公安局网内查询个人身份证信息后，同步读取人才网入库信息
6:个人职称评审加20分
7:个人信誉贷款加10分
8:在国家人才网主办的国家网络招聘大会中纳入资料，供国家高端企业选择人才
Micronuclei test.M.sc.zoology.fisheries.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/Nucleophilic Addition of carbonyl compounds.pptx
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
Applied Science: Thermodynamics, Laws & Methodology.pdf
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
Nucleic Acid-its structural and functional complexity.
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social selection
- 2. Natural selection tends to produce individuals that are well adapted to their environment. However, sexual selection does not adapt the individual to the environment but does enhance traits involved in mate acquisition. Moreover, sexual selection can produce individuals with such elaborate ornaments that they must be either energetically costly to develop, costly to maintain, or even lead to a direct survival cost for the individual that bears the ornament.Darwin's theory of sexual gave a plausible explaination for the origin of many splendid if not bizarre ornaments.
- 3. Sexual selection Darwin’s second “major” book: 1871 On the Descent of Man, and Selection in Relation to Sex Why a theory of sexual selection? Darwin needed a theory to explain the many extravagant traits that seem to reduce survival e.g. the peacock’s tail What is sexual selection? Sexual selection is distinguished from natural selection by the following criterion: Sexual selection arises through variance in mating success
- 4. Sexual selection Is sexual selection different from natural selection? Darwin saw them as distinct - only sexual selection could produce traits that compromise survival The basic principles are identical – selection favors whatever gets more genes into the next generation In sexual selection, fitness is measured relative to members of the same sex Two kinds of sexual selection Intrasexual selection – mating success determined by within-sex interactions e.g., male-male combat Intersexual selection – mating success determined by between-sex interactions e.g., female choice of males
- 5. The peacock’s tail Extravagant male ornaments The peacock’s tail greatly impairs his mobility…how could such a trait evolve?
- 6. Male ornaments Long-tailed widowbird Males with unnaturally long tails attract females away from the nests of “normal” males or males with shortened tails
- 7. Hypotheses for male ornaments Fisher’s “runaway” hypothesis Mate choice originally evolved to facilitate adaptive choice for traits conferring a survival advantage Once female preference evolved, any genes that conferred survival advantage but compromised attractiveness would not be passed on because surviving males would fail to mate Zahavi’s “handicap” hypotheses Extravagant male traits are costly to develop and maintain Choosing a mate with “good genes” requires an honest signal of genetic quality Only males in good condition (those with good genes) will be able to fully develop and maintain an ornament Amotz Zahavi Ronald Fisher