This presentation file has these contents:
Evolution
Convergent Evolution
Analogous structures
Divergent Evolution
Homologous structures
Parallel Evolution
Coevolution
Types of Evolution
Macroevolution
Microevolution
Importance of pattern of evolution
This presentation file has these contents:
Evolution
Convergent Evolution
Analogous structures
Divergent Evolution
Homologous structures
Parallel Evolution
Coevolution
Types of Evolution
Macroevolution
Microevolution
Importance of pattern of evolution
To determine the variation and the limitation between species, many concepts have been proposed.
When a taxonomist study a particular taxa, he/she must adopted a species concept and provide a species limitation to define this taxa.
Plant kingdom as other living kingdoms has a hierarchy structure ends mostly with species rank.
Species are one of the basic units to compare in almost all fields of biology.
A species is defined as the largest group of organisms in which two individuals are capable of reproducing fertile offspring, typically using sexual reproduction.
Definition of a species as a group of interbreeding individuals cannot be easily applied to organisms that reproduce only or mainly asexually.
If two lineages of oak look quite different, but occasionally form hybrids with each other, should we count them as different species?
Idea of a species is something that we humans invented for our own convenience.
‘‘No matter what variations occur in the individuals or the species, if they spring from the seed of one and the same plant, they are accidental variations and not such as distinguish a species permanently; one species never springs from the seed of another nor vice versa” - JOHN RAY.
Used a sexual system ‘‘natural system” for defining species - LINNAEUS.
‘‘A species is a collection of all the individuals which resemble each other more than they resemble anything else, which can by natural fecundation produce fertile individuals, and which reproduce themselves by generation, in such a manner that we may from analogy suppose them all to have sprung from one single individual” - DE CANDOLLE.
Classical and molecular taxonomic parameters, species concept, systematic gradation of animals, nomenclature, modern scheme of animal classification into sub-Kingdom, division, section, phyla and minor phyla
To determine the variation and the limitation between species, many concepts have been proposed.
When a taxonomist study a particular taxa, he/she must adopted a species concept and provide a species limitation to define this taxa.
Plant kingdom as other living kingdoms has a hierarchy structure ends mostly with species rank.
Species are one of the basic units to compare in almost all fields of biology.
A species is defined as the largest group of organisms in which two individuals are capable of reproducing fertile offspring, typically using sexual reproduction.
Definition of a species as a group of interbreeding individuals cannot be easily applied to organisms that reproduce only or mainly asexually.
If two lineages of oak look quite different, but occasionally form hybrids with each other, should we count them as different species?
Idea of a species is something that we humans invented for our own convenience.
‘‘No matter what variations occur in the individuals or the species, if they spring from the seed of one and the same plant, they are accidental variations and not such as distinguish a species permanently; one species never springs from the seed of another nor vice versa” - JOHN RAY.
Used a sexual system ‘‘natural system” for defining species - LINNAEUS.
‘‘A species is a collection of all the individuals which resemble each other more than they resemble anything else, which can by natural fecundation produce fertile individuals, and which reproduce themselves by generation, in such a manner that we may from analogy suppose them all to have sprung from one single individual” - DE CANDOLLE.
Classical and molecular taxonomic parameters, species concept, systematic gradation of animals, nomenclature, modern scheme of animal classification into sub-Kingdom, division, section, phyla and minor phyla
Endospores_Dr Jagadisha T V _CSD 2nd pptxJagadishaTV
Formed inside the parent vegetative cell.
➢ Endospores are highly durable dehydrated cells,
which can survive extreme heat, lack of water,
freezing and exposure to many toxic chemicals
and radiation.
➢ Endospores also called as “resting cells”.
Teratogens jagadisha T V. and its effects in fetal developmentJagadishaTV
Teras-”monster” Gensis-”producing”
A teratogen is defined as any agent that results in structural or functional abnormalities (malformation ) in the fetus, or in the child after birth, as a consequence of maternal exposure during pregnancy.
Birth defects are known to occur in 3- 5% of all newborns.
They can do direct damage to the fetus, causing abnormal development.
Cytogenetics_ Chromosmes_Dr Jagadisha T V_PPT.pptxJagadishaTV
●To study the structure of chromosomes.
● To understand the concepts of linkage and crossing over.
● To understand structural and numerical chromosomal aberrations.
Introduction, Types-somatic and germinal; Mechanism of meiotic crossing oversynapsis, duplication of chromosomes, breakage and union, terminalization;
Cytological basis of crossing over - Stern’s experiment in Drosophila; Creighton
and McClintock’s experiment in Maize; Crossing over in Drosophila, Construction
of genetic maps in Drosophila - two point and three-point crosses; Interference and
coincidence.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
1. Isolating mechanisms
Dr. Jagadisha T.V., M. Sc., PGDGT., PhD
Assistant Professor
Department of Life Sciences (Genetics)
Kristu Jayanti college
Ph.-No: 8892698143/9449442521,
E-mail:jagadisha.tv@kristujayanti.com
ORCID ID: https://orcid.org/0000-0002-0596-7830
Research Gate Profile: https://www.researchgate.net/profile/Jagadish-T-V
2. Isolation
• Any external or internal barrier, that
prevents interbreeding between
populations, is called isolation.
• As a result, the population of a species is
either separated into smaller units or the
exchange of genes (gene flow) between
them is prevented
3. • -Isolation is the separation of the population of a particular species into
smaller units which prevents interbreeding between them.
• -Some barrier that prevents gene flow or exchange of genes between
isolated populations is called isolating mechanism.
• -A number of isolating mechanisms are operated in nature and therefore
divergence and speciation may occur.
• -The isolating mechanism is of two types namely geographical isolation
and reproductive isolation.
Isolation Mechanism
4. • The reproductive characteristics that prevent interbreeding between different species
• They are important for maintaining the biological species concept, which defines
species by reproductive isolation
• There are different types of isolating mechanisms, such as
• Geographical
• Reproductive
Isolating mechanisms
8. Geographical Isolation
• The separation of species by physical barriers like water forms, oceans, mountains,
etc.
• The organisms are ultimately separated from exchanging genetic material with
other organisms of the same species
• As there are fewer chances for variations to occur, new species are not formed in
asexually reproducing individuals undergoing geographic isolation
• This type of isolation can lead to the development of distinct genetic and physical
characteristics in different populations, and ultimately, the evolution of new
species
9. I. GEOGRAPHICAL ISOLATION
• It is also called as physical isolation.
• it occurs when an original population is divided into two or more groups
by geographical barriers such as river, ocean, mountain, glacier etc.
• -these are barriers prevent interbreeding between isolated groups.-The
separated groups are exposed to different types of environmental factors
and they Requires new traits by mutation.
• •The separated Population develop distinct gene pool and they do not
interbreed. Thus new spacies have been formed by geographical isolation
e.g Darwin's finches Original population
10.
11.
12. • An earthquake causes two
populations to become separate from
each other.
• Over time, each species experiences
genetic makeup specific only to their
own smaller, less diverse populations.
13. Reproductive isolation
The inability of a species to breed successfully with related species due to
• Geographical
• Behavioral
• Physiological
or
• Genetic barriers or differences
17. Reproductive isolation
• is a key concept in evolutionary biology, referring to the mechanisms
that prevent different species from interbreeding or producing viable
and fertile offspring when they do attempt to mate.
• There are several types of reproductive isolation, and they can be
categorized into two main groups
• : prezygotic barriers and postzygotic barriers.
30. Temporal isolation
• A type of reproductive isolation mechanism among sexual organisms
in which the differences in the timing of critical reproductive events
prevent members of closely related species
31.
32.
33.
34. courtship is the period wherein some couples get to know each other prior to a possible marriage or committed
romantic, de facto relationship
35.
36.
37.
38.
39. 1. Prezygotic Barriers:
• These barriers occur before the formation of a zygote (fertilized egg).
• a. Geographic Isolation:
• Populations are separated by geographic barriers such as mountains, rivers, or oceans.
Over time, this can lead to the development of distinct species. Example: The
Galápagos finches, where different species evolved on different islands due to
geographic isolation.
• b. Temporal Isolation:
• Species may have different mating seasons or times of day when they are active,
preventing them from encountering each other for mating. Example: Two species of
frogs, one that breeds in the spring and another in the summer, do not interbreed.
40. c. Behavioral Isolation: Species have different courtship rituals, behaviors, or signals that prevent
them from mating with individuals of other species. Example: Male fireflies use specific light
patterns to attract females of their own species; if the pattern is not matched, mating does not
occur.
d. Mechanical Isolation: The reproductive organs of two species are structurally incompatible,
making it physically impossible for them to mate. Example: Some species of snails have shells that
coil in different directions, preventing them from mating.
e. Gametic Isolation: Even if mating occurs, the sperm of one species may not be able to fertilize
the egg of another species due to differences in gametes (sperm and egg) or their chemical
compatibility. Example: Sea urchin sperm may not successfully fertilize the eggs of a different
species due to gametic differences.
41.
42.
43.
44.
45.
46.
47. Gametic Mortality
Gametic mortality refers to the death or failure of reproductive cells (gametes) before they
can successfully fertilize and contribute to the formation of a new organism.
Gametes are specialized cells involved in sexual reproduction: sperm in males and eggs (ova)
in females.
Gametic mortality can occur for various reasons, including
Genetic abnormalities
Environmental factors, or physiological issues.
Gametes are unable to successfully fuse during fertilization due to problems such as
Genetic mutations,
chromosomal abnormalities, or the inability to reach each other in the reproductive
tract
It can result in the failure to conceive or produce viable offspring.
48.
49. Bufo fowleri
• Mating and sperm transfer takes place but egg is not fertilized.
• In Drosophila vaginal wall swells killing spermatozoa should interspecific crosses
take place.
• If mating takes place between Bufo fowleri and Bufo valliceps, sperms cannot
penetrate the egg membrane of each other, leading to the mortality of gametes.
Bufo valliceps
50.
51.
52.
53.
54. 2. Postzygotic Barriers:
• These barriers occur after the formation of a zygote (fertilized egg).
• a. Hybrid Inviability: The zygote is formed but does not develop properly, leading to the death of the
hybrid embryo. Example: A horse and a donkey can mate to produce a mule, but mules are often
sterile and unable to reproduce.
• b. Hybrid Sterility: Hybrids may develop but are sterile, preventing gene flow between species.
Example: The hybrid between a lion and a tiger, called a liger, is often sterile.
• c. Hybrid Breakdown: The first-generation hybrids may be viable and fertile, but when they mate with
each other or with either parent species, the subsequent generations are often weak or infertile.
Example: Some cultivated rice varieties show hybrid breakdown when the second-generation hybrids
have reduced yield and quality.
Reproductive isolation mechanisms play a crucial role in the process of speciation, where new species
arise as populations become reproductively isolated from one another and accumulate genetic
differences over time
55.
56. DOBZHANSKY-MULLER MODEL
• The Dobzhansky-Muller model, also known as the Dobzhansky-Muller incompatibilities or
speciation genes model, is a theoretical framework in evolutionary biology that helps explain
the genetic basis of reproductive isolation between two diverging populations or species.
• This model was developed independently by two prominent evolutionary biologists,
Theodosius Dobzhansky and Hermann J. Muller, in the mid-20th century.
57. • The central idea of the Dobzhansky-Muller model is that when two populations of a common
ancestral species diverge and accumulate genetic changes (mutations) independently over time,
they may eventually become reproductively isolated from each other.
• It means that individuals from these two populations can no longer interbreed or produce viable and
fertile offspring
• The model proposes that these reproductive barriers arise due to the evolution of genetic
incompatibilities between the genes of the two populations.
• Specifically, it suggests that when alleles (alternative forms of genes) from one population interact
with alleles from the other population, they can produce negative epistatic interactions.
• Negative epistasis occurs when the combined effect of two alleles together is deleterious, even if
each allele is individually functional or beneficial within its own population
58. The key elements of the Dobzhansky-Muller model are:
Ancestral Population: Initially, there is a single, interbreeding population.
Genetic Divergence: Over time, this population becomes geographically isolated or
undergoes genetic changes due to various factors like mutation, natural selection,
genetic drift, or geographic isolation. These changes result in the accumulation of
different alleles in each population.
Incompatibility Alleles: Some of the alleles in each population may be functionally
adapted to the genetic background of that population. However, when individuals from
these divergent populations come into contact or attempt to mate, certain
combinations of alleles may lead to incompatibilities. These incompatibilities can result
in reduced fitness or reproductive failure in hybrid offspring.
59. Reproductive Isolation:
• The genetic incompatibilities between the populations act as a barrier to gene flow.
• This can lead to reproductive isolation, where hybrids between the populations have
reduced fitness or are inviable, preventing further interbreeding between the
populations
60. • In the ancestral population, the genotype is AABB.
• When two populations become isolated from each other, new mutations can arise.
• In one population A evolves into a, and in the other B evolves into b.
• When the two populations hybridise it is the first time a and b interact with each other.
• When these alleles are incompatible, we speak of Dobzhansky–Muller incompatibilities.
61. Significance of isolating mechanism.
The isolating mechanism protects the gene pool of a species and prevents hybridization.
It prevents the wastage of gametes and energy.
A weak isolating mechanism leads to the production of new species through hybridization.
The absence of an isolating mechanism leads to the production of new species by instant
speciation.
Geographical isolation followed by reproductive isolation ultimately leads to the production of
new species.
Isolating mechanisms protect the identity of a species, which all species fiercely guard