This document discusses the factors that can cause microevolution in a population. It defines microevolution as changes in a species' gene pool over a short period of time due to reproductive individuals. Five factors are described: 1) mutation pressure introduces new alleles, 2) immigration changes gene frequencies, 3) genetic drift impacts small populations, 4) non-random mating disrupts Hardy-Weinberg assumptions, and 5) selection pressure favors better adapted individuals who reproduce more. These factors disrupt genetic equilibrium and cause populations to evolve over multiple generations.
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.
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
This document will help you and will clear your concepts about the terms of Orthogenesis, Allometry & Adaptive Radiations, which are usually studied in evolution.
Two broad categories of behaviors are Proximate and Ultimate behaviour. The presentation gives a brief introduction on Proximate and Ultimate causes of behaviour
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.
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
This document will help you and will clear your concepts about the terms of Orthogenesis, Allometry & Adaptive Radiations, which are usually studied in evolution.
Two broad categories of behaviors are Proximate and Ultimate behaviour. The presentation gives a brief introduction on Proximate and Ultimate causes of behaviour
Population genetic analysis, Finding out gene frequencies in a population, description of how Selection, mutation, migration brings a change in allelic frequencies of a population.
Evidence of Evolution by Natural Selection - how basic evolutionary principal...Madison Elsaadi
This PPTP is made for high school teachers wishing to introduce evolutionary concepts and exercises in regular and advance (AP) high school science courses.
ASSORTIVE MATING AND GENE FREQUENCY CHANGES (POPULATION GENETICS)316116
This slide briefly the explanation of random mating as deviation from the Hardy-Weinberg equilibrium and also the changes in gene frequency as a result of violation of Hardy-Weinberg assumptions on gene frequency
This presentation covers the basic terminology and key parameters of Population Genetics. Presentation is helpful for the students of Life Sciences and Evolutionary biology.
evolution of human evolution of human evolution of human evolution of human evolution of human evolution of human evolution of human. human evolution human evolution human evolution human evolution . population and evolution population and evolution population and evolution
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.
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.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
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.
Richard's aventures in two entangled wonderlandsRichard 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.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
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.
2. Microevolution
• Microevolution is the change in the genome,
or gene pool, for a given species in a relatively
short period of geologic time by the
alterations of successfully reproducing
individuals within a population.
3. • Some environmental conditions are more
harsh than others, and organisms may have to
adapt more to survive in that conditions.
• Areas where the environmental pressures are
stable, or the organisms have adapted to it,
exhibit non-evolving populations.
• In a non-evolving population, the allele
frequency, genotype frequency,
and phenotype frequency remain in genetic
equilibrium.
4. • This phenomenon was illustratedd by a
German physician, Weinberg, and a British
mathematician, Hardy, both working
independently in 1908. Their combined efforts
are now known as the Hardy-Weinberg
equilibrium model.
5. Hardy-Weinberg Equilibrium
• To understand the Hardy-Weinberg equilibrium,
assume G and g are the dominant and recessive
alleles for a trait where GG = green, gg = yellow,
and Gg = orange.
• In our imaginary population of 1,000 individuals,
assume that 600 have the GG genotype, 300 are
Gg, and 100 are gg. The allele and genotype
frequency for each allele is calculated by dividing
the total population into the number for each
genotype:
6. • GG = 600/1,000 = .6
• Gg = 300/1,000 = .3
• gg = 100/1,000 = .1
• The frequency of the allele in the first
generation of offspring.
7. • First, determine the total number of alleles
possible in the first generation. In this
imaginary case, because each organism has 2
alleles and there are 1,000 organisms, the
number of possible alleles in the first
generation of offspring is:
• 2 × 1,000 = 2,000
8. • For the G allele, both GG and Gg individuals
must be considered. Taken separately,
• GG = 2 × 600 = 1,200
• + Gg = 300
• 1,500
9. • The letter p is used to identify the allele
frequency for the dominant allele (.75) and q
for the recessive allele (.25).
• Note that p + q = 1.
• The frequency for the G allele is therefore:
• 1,500/2,000 = .75
10. • For the g allele, the calculation is similar:
• Gg = 300
• + gg = 2 × 100 = 200
• 500
• The frequency for the g allele is therefore:
• 500/2,000 = .25
11. • Hardy-Weinberg can also predict second-
generation genotype frequencies. From the
previous example, the allele frequencies for
the only possible alleles are p = .75(G) and q =
.25(g) after meiosis. Therefore, the probability
of a GG offspring is p × p = p2 or (.75) × (.75) =
55 percent. For the gg possibility, the allele
frequencies are q × q or (.25) × (.25) = 6
percent. For the heterozygous genotype, the
dominant allele can come from either parent,
so there are two possibilities:
• Gg = 2pq = 2(.75)(.25) = 39 percent.
12. • Note that the percentages equal 100, and the
allele frequencies (p and q) are identical to the
genotype frequency in the first generation!
Because there is no variation in this
hypothetical situation, it is in Hardy-Weinberg
equilibrium, and both the gene and allele
frequencies will remain unchanged until acted
upon by an outside force(s). Therefore, the
population is in a stable equilibrium with no
change in phenotypic characteristics.
13. The Hardy-Weinberg equation highlights the
fact that sexual reproduction does not alter
the allele frequencies in a gene pool.
• Five factors impact the Hardy-Weinberg
equilibrium and create their own method
for microevolution.
• 1.Mutation pressure
• 2.Immigration
• 3.Genetic drift
• 4.Cross breeding
• 5.Selection pressure
14. 1.Mutation pressure
• A mutation is an inheritable change of a gene by
one of several different mechanisms that alter
the DNA sequencing of an existing allele to create
a new allele for that gene
• A primary mechanism for microevolution is the
formation of new alleles by mutation.
Spontaneous errors in the replication of DNA
create new alleles instantly while physical and
chemical mutagens, such as ultraviolet light,
create mutations constantly at a lower rate.
15. • Mutations affect the genetic equilibrium by
altering the DNA, thus creating new alleles that
may then become part of the reproductive gene
pool for a population. When a new allele creates
an advantage for the offspring, the number of
individuals with the new allele may increase
dramatically through successive generations. This
phenomenon is not caused by the mutation
somehow overmanufacturing the allele, but by
the successful reproduction of individuals who
possess the new allele. Because mutations are
the only process that creates new alleles, it is the
only mechanism that ultimately increases genetic
variation
16. 2.Immigration
Gene migration is the movement of alleles
into or out of a population either by the
immigration or emigration by individuals or
groups. When genes flow from one population
to another, that flow may increase the genetic
variation for the individual populations.
17. 3.Genetic Drift
• Genetic drift is the phenomenon whereby chance
or random events change the allele frequencies
in a population. Genetic drift has a tremendous
effect on small populations where the gene pool
is so small that minor chance events greatly
influence the Hardy-Weinberg arithmetic. The
failure of a single organism or small groups of
organisms to reproduce creates a large genetic
drift in a small population because of the loss of
genes that were not conveyed to the next
generation
18. • Conversely, large populations, statistically
defined as greater than 100 reproducing
individuals, are proportionally less affected by
isolated random events and retain more stable
allele frequency with low genetic drift.
19. 4.Cross breeding
• The Hardy-Weinberg equation assumes that all
males have an equal chance to fertilize all
females. However, in nature, this seldom is true .
In fact, the ultimate nonrandom mating is the act
of self-fertilization that is common in some
plants. In other cases, as the reproductive season
approaches, the number of desirable mates is
limited by their presence (or absence) as well as
by their competitive premating rituals. Finally,
botanists and zoologists practice nonrandom
mating as they attempt to breed more and better
organisms for economic benefit.
20. 5.Selection pressure
• The process by which comparatively better
adapted individuals out of a heterogeneous
population are favoured by the Nature over
the less adapted individuals is called natural
selection.
• The process of natural selection operates
through differential reproduction.
21. • It means that those individuals, which are best
adapted to the environment, survive longer and
reproduce at a higher rate and produce more
offsprings than those which are less adapted.
• So the formers contribute proportionately greater
percentage of genes to the gene pool of next
generation while less adapted individuals
produce fewer offsprings. If differential
reproduction continues for a number of
generations, then the genes of those individuals
which produce more offsprings will become
predominant in the gene pool of the population.