Evolution
Types of evolution
Biological Species Concept
Other Species Definitions
Barriers in Evolution
Reproductive Isolation
Reproductive Isolation’s types
Prezygotic Reproductive Isolating Barriers
Ecological isolation
Ecological isolation’s types
Postzygotic Reproductive Isolating Barriers
Speciation
Types of Speciation
How Does Speciation Occur?
This Presentation is especially for the grade 10 as it is informaive and can be used for the CBSE syllabus of india ( of course ). hope this helps you alot and if any problems please let me know from the comments section below.................peace out......... and message me at bavitharavi@hotmail.com. this is also the chpter 9 of the cbse gr 10 science book biology.
Evolution
Types of evolution
Biological Species Concept
Other Species Definitions
Barriers in Evolution
Reproductive Isolation
Reproductive Isolation’s types
Prezygotic Reproductive Isolating Barriers
Ecological isolation
Ecological isolation’s types
Postzygotic Reproductive Isolating Barriers
Speciation
Types of Speciation
How Does Speciation Occur?
This Presentation is especially for the grade 10 as it is informaive and can be used for the CBSE syllabus of india ( of course ). hope this helps you alot and if any problems please let me know from the comments section below.................peace out......... and message me at bavitharavi@hotmail.com. this is also the chpter 9 of the cbse gr 10 science book biology.
Speciation is the evolutionary process by which reproductively isolated biological populations evolve to become distinct species.There are few mechanisms through which this process can be well understood.
It states that the present day complex plants and animals have evolved from earlier simpler forms of life by gradual changes. SEQUENTIAL EVOLUTION ,DIVERGENT EVOLUTION, Theories of evolution.
Salas, V. (2024) "John of St. Thomas (Poinsot) on the Science of Sacred Theol...Studia Poinsotiana
I Introduction
II Subalternation and Theology
III Theology and Dogmatic Declarations
IV The Mixed Principles of Theology
V Virtual Revelation: The Unity of Theology
VI Theology as a Natural Science
VII Theology’s Certitude
VIII Conclusion
Notes
Bibliography
All the contents are fully attributable to the author, Doctor Victor Salas. Should you wish to get this text republished, get in touch with the author or the editorial committee of the Studia Poinsotiana. Insofar as possible, we will be happy to broker your contact.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
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.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
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.
2. Achievement Standard
Evolutionary processes involve the following biological ideas:
Role of mutation
Gene flow
Role of natural selection and genetic drift
Modes of speciation (sympatric, allopatric)
Reproductive isolating mechanisms that contribute to speciation (geographical, temporal,
ecological, behavioral, structural barriers, polyploidy)
Patterns such as divergence, convergence, adaptive radiation, co-evolution, punctuated
equilibrium, and gradualism.
Scientific evidence for evolution, which may include examples from New Zealand’s flora and
fauna, will be selected from:
fossil evidence
Comparative anatomy (homologous and analogous structures)
Molecular biology (proteins and DNA analysis)
Biogeography.
3. The Basics
Terms:
Genes – carry the genetic information required for cell growth, functioning and replication
Alleles – alternative form of a gene (creates variation)
Gene Pool – all the alleles of a population
Gene Flow – movement of alleles in and out of a population
Speciation - evolution of new species, new species cannot reproduce with old species
Mutation – change in the base sequence in DNA, must occur in gametes to be passed on.
Creates totally NEW phenotypes.
Bottleneck Effect – massive loss of alleles due to natural disaster, leaves a non
representative population
Founder Effect – small non representative group migrate to a new habitat
Genetic Drift – random loss of alleles due to chance in a small population
4. Natural Selection
Natural Selection – those best suited to their
environment mate and pass on their genes to the
next generation increasing the number of these
helpful genes in the gene pool, meanwhile those
unsuited do not mate and those genes disappear
from the gene pool.
Stabilizing selects against the two extremes and
favors the middle (2)
Directional selects against one of the extremes (3)
Disruptive selects against the middle and favors the
two extremes, this can lead to speciation (1)
5. Variation
Differences between individuals in a species, caused by
differences in the DNA base sequence
The more differences in a species the greater chance that
some of the species will survive changes within their
environment
Variation is created during sexual reproduction, meiosis (crossing
over, independent assortment, segregation) immigration and
mutations
Variation must occur within the gametes in order to be passed
on
Variation is reduced by natural selection, genetic drift
(bottleneck effect, founder effect), emigration and natality.
6. Speciation
One species evolves into two or more species that can no
longer interbred.
Usually occurs as a result of adaptation to new ecological
niches and in response to the occurrence of new variations
within the species that make an organism better able to survive
and reproduce
7. Speciation
There are three ways in which new species
can evolve:
1. Instant Speciation
Occurs within one generation as a result of
polyploidy
more than two sets of chromosomes
Usually occurs in plants
8. Speciation
2. Sympatric Speciation
Occurs when a new species arises in the SAME
territory as the parent species
Often occurs as a result of niche differentiation
(ie finches living in top of trees vs forest floor)
3. Allopatric Speciation
Occurs when a new species evolves as a result
of being isolated from the parent species
NEW territory
Often occurs when there is some kind of
geographical or environmental disturbance
9. Polyploidy and Aneuploidy
Poly – many, polyploidy = more than one set of chromosomes
Aneu – one, aneuploidy = one chromosome is represented
three times instead of the usual two (one from each parent)
Homologous Chromosomes usually separate during meiosis to
create two gametes with haploid (n, half the original)
chromosomes
Non disjunction – when homologous pairs of chromosomes fail
to separate during meiosis the gametes can end up with:
Having two copies of a single chromosome (aneuploidy)
Having a missing chromosome (aneuploidy)
Having 2 whole sets of chromosomes (polyploidy)
Having NO chromosomes (zygote is unlikely to form in this case)
10. Offspring formed from these gametes end up having:
3 or more of an individual chromosome – aneuploidy
3 or more sets of chromosomes – polyploidy
Polyploidy generally only occurs in plants and can be advantageous as often
results in bigger better crops, or seedless crops (infertile plants have no seeds!)
11. Aneuploidy in the sex chromosome in
humans can result in:
Turners Syndrome – XO
Klinfelters Syndrome – XXY
Aneuploidy in an autosomal
chromosome in humans can result in:
Downs Syndrome – trisomy 21 – 3 number
21 chromosome
Edwards Syndrome – trisomy 18 – 3
number 18 chromosomes
12. Types of Polyploidy
Polyploidy can result in both sterile and fertile offspring
In order to be fertile an organism needs to have an EVEN number of chromosomes (so they
can line up in homologous pairs and separate during meiosis
Autopolyploids – organisms with multiple sets of chromosomes from the SAME species
Eg a potato produces gametes with polyploidy (more than one set of chromosomes) and mates
with another potato giving rise to a new potato with autopolyploidy (3 sets of chromosomes but all
from the potato family)
Often occurs when plants self fertilize
If both gametes have undergone non disjunction then the offspring will be fertile as it will be have
an even number of chromosomes -4n or tetraploid
If only one gamete has undergone non disjunction it will result in infertile offspring as there will be
an uneven number of chromosomes – 3n or triploid
13. Allopolyploids – organisms with multiple sets of chromosomes from DIFFERENT species
Eg a wheat plant fertilizes a rye plant
If the offspring has an uneven number of chromosomes due to non disjunction having occurred in one of
the gametes then the offspring will be infertile
If the offspring has an even number of chromosomes due to non disjunction occurring in both gametes
then the offspring will be fertile
If the uneven numbered gamete manages to fuse with another normal gamete and a plant with even
chromosomes arises then it will be a fertile hybrid – this usual occurs as a result of self fertilisation.
Hybrid – made from two different species
14.
15. Isolating Mechanisms
In order for a new species to arise it must not be able to reproduce with
the parent species.
Prevention of reproduction can occur in several ways:
1. Pre Zygotic (before a zygote is formed)
Geographical – separated by space, river, ocean, mountain, road etc
Temporal –reproducing at different times of year, active at different times of day
Ecological – live in different ecological niches
Behavioural – different courtship behaviours
Structural barriers – reproductive genitalia incompatible
Gamete incompatibility – pollen grains don’t grow pollen tubes
16. 2. Post Zygotic (once zygote has formed)
Polyploidy – multiple sets of chromosomes, in an uneven number so that
offspring are infertile
Hybrid Inviability – zygote is aborted as has chromosomal
incompatibility
Hybrid Sterility – off spring survives but is sterile – mule
Hybrid breakdown – hybrid is fertile but its offspring are sterile
17. Evolution
Evolution - the gradual change in species over long periods
of time resulting in establishment of a new species, (lots of
speciation's occurring one after the other over millions of
years!)
Variation of alleles exists within the population
The organisms are exposed to a selective pressure such as
a changing environment
Those with favorable phenotypes are more likely to survive
and reproduce while those with less favorable phenotypes
have less chance of surviving and reproducing. “survival of
the fittest”
Each generation will be better adapted to the current
environment.
18. Patterns of Evolution
Speciation or evolution can occur in a variety of ways:
Divergence (A)
Common ancestor, but no longer look the same
Humans and apes from a common primate ancestor
Convergence (B)
Unrelated ancestor, but look similar due to similar selction pressures due to living in similar environment
Whales and fish look the same as both live in water but NOT related
Parallel Evolution (C)
Unrelated ancestor, dissimilar environment but still look similar
Adaptive radiation
Co-evolution
Species which are unrelated but have a close ecological relationship exert selection pressures on each other
Predator /prey eg flowers grow to allow certain birds to pollinate, birds develop long beaks so can get pollen
19. Rate of Evolutionary Change
Gradualism
Slow progressive change over time
Punctuated equilibrium
Generally slow change but with periods of rapid
evolution
Caused by rapid and extreme changes to the
environment
Eg ice age, volcanic eruption
20. Evidence for Evolution
Fossils – comparison to current day species
Comparative Anatomy
Homologous structures
Same origins but different function
Forelimb bones of birds, humans, whales, bats
Analogous structures
Different origins but similar functions
Wings of bats, birds, and moths
21. Embryology
The more similar embryos are of different species the less time has past
since they diverged
Bio geographical – geographical origins of current species
distributions
Biochemical – similarities between DNA and proteins