10- Evolution

Microevolution

Evolutionary change on a small scale and focuses on population. Specifically, changes in a populations allele frequencies over time

Macroevolution

Evolutionary change on a large scale that occurs over long periods of time. Explains how species diverge into one or more different species

Mechanisms of Microevolution; How do they influence allele frequency

• Mutations

• Gene Flow

• Genetic Drift

• Natural Selection

  They all influence allele frequency because they explain how gene flow and change in populations

What are mutations

Random changes in the DNA sequences caused by various reasons. Mutation in genes create allele

Why are mutations the ultimate source of genetic variation?

Results in differences in the DNA sequences among individuals

Why are all mutations important to evolution?

No, not all mutations are important to evolution as some mutations like in color or other ways can provide no benefit at all.

Emigrations vs Immigration

• Emigration: Exits a population

• Immigration: Enters a population

How does gene flow impact a populations genetic variation

Introduces new genes or alleles from one population to another, increasing the variation

Genetic Drift w/ examples

Random fluctuations in the frequency of an allele in a population

• EX: Weather kills part of population, or part of the population leaves the whole population

Genetic Bottleneck. Examples?

Decrease in population size due to random catastrophic events (Predation, disease, extreme weather events)

• EX: Some ants in a population are killed off due to a falling boulder

Why is genetic drift more pronounced in small populations

Genetic variation is high, and taking out a part of the population will not effect it as much as a small population, which already has little to no genetic variation

How does genetic drift impact the genetic diversity of populations

Asa portion of the members in a population are lost, the genetic variation will decrease.

How does climate change and genetic drift impact polar bear populations

Climate changes causes pieces of ice, that polar bears live on, to fragment. This seperates the populations and leads to genetic drift. This drift divides their population and places them at greater risk of extinction

How does natural selection work

Individuals with inherited traits, more desirable by the environment and ecosystem, will tend to survive and reproduce at higher rates than others because of these traits.

What is meant by fitness and adaptation

Fitness is the ability to survive and pass its genetic material. Adaptation is the ability to inherit characteristics that will enhance survival and reproduction in certain environments

What are the three requirements necessary for natural selection to act on a population

• Variation for a trait in a population is present

• Must be heritable

• Reproductive success

How does natural selection act on pepper moth populations during the industrial evolution

During the inductrial revolution, due to the amount of increased air pollution, tree trunks and walls became darker. Salt-white moths were now able to be seen much more easily by predators while pepper moths were hidden and harder to spot, increasing it’s survival.

How does natural selection work with Anti-biotic resistance in bacteria

Bacteria dies when exposed to anti-biotics, but a bacteria developed a mutation allowing to become anti-biotic resistant and survive, allowing it to live longer to replicate and pass on it’s mutation.

How does natural selection work with sickle-cell carriers for sickle cell disease

Populations that have not inherited any sickle-cell alleles were susceptible to malaria infections, but individuals who were diagnosed with sickle-cell diseases died due to it. Only carriers of the disease lived as they gained immunity to both dieasese and infection, lived longer, and passed down this trait to their children.

How does natural selection work with pesticide-insecticide resistance in GMO crops

Insects who fed on GMO plants that contained insecticide or pesticide died shortly, but some insects may have developed resistance due to long time exposure, allowing them to live longer and pass down their traits

How does natural selection and fitness apply to immunocompromised populations during the corona virus pandemic

People whp were immunocomprimised had a much harder time coming back into society because the effects of COVID were extreme for them.

Sexual selection

Form of natural selection that produces resproductive success based on the ability to obtain mating partners

Intrasexual vs Intersexual selection

• Intrasexual selection: Competition between males for access to females. Favors traits that increases a male’s ability to fertilize as many eggs as possible

• Intersexual Selection: Interaction between the sexes, typically involving mate choices. Females tend to be more choosy, looking for specific traits to determinewhich will maximize their fitness

Artificial selection. What is the difference between that and natural selection

The process of selection conducted under human direction. Works the same as natural selection, except that natural selection is nature, not human interference. Also known as selective breeding

Species and reproductive isolation

• Species: Group of individuals whose members have the potential o interbreed in nature and produce viable, fertile offspring

• Reproductive isolation: Inability of individuals of two populations to produce fertile offspring with each other.

Exceptions to biological species concept.

• Asexual reproducing organisms

  • Bacteria that reproduces asexually rather than forming from sexual reproduction (combination of gametes to produce offspring)

• Extinct Species

  • There is not a clear way to tell from the fossil record to determine if extinct species were capable of mating with each other

Speciation

Development of new species through the process of evolution

Allopatric vs sympatric speciation

• Allopatric Speciation

  • Group population has been separated from the parent population - usually because of a geographic separation as time goes by

• Sympatric Speciation

  • Occurs even thought two groups still occupy hat same geographic area

Pre-zygotic isolating mechanisms: Ecological isolation

Population occupy the same territory, but live in different habitats so they don’t meet

Pre-zygotic isolating mechanisms: Temporal isolation

Keeps individuals of different species from interbreeding even if they live in the same area

• Species will breeding different times of day, seasons and cannot mix gamates

Pre-zygotic isolating mechanisms: Behavioral Isolation

Two populations are capable of interbreeding develop differences in courtship rituals/behaviors

Pre-zygotic isolating mechanisms: Gametic Isolation

Mechanism in which mating takes place, but fertilization is unsuccessful

Post-zygotic isolating mechanisms: Hybrid inviability

Gametes from two species may combine but genetic informations insufficient to carry the organism through normal development

Post-zygotic isolating mechanisms: Hybrid breakdown

Two related species can create hybrids and are fertile, but successive generation suffer lower viability — cannot create established population

Post-zygotic isolating mechanisms: Hybrid Sterility

Some species are closely related enough to produce viable hybrids, but the hybrids are sterile

Phylogenetic Trees

Depict evolutionary relationships based on descent with modification and represent hypotheses bout evolutionary history

How does fossil record support evolution

Displays history life recorded by remains from the past. It shows patterns of succession of life forms from the simple to the most complex s one goes up through to the new layers

How does comparative anatomy structure support evolution

It shows that characteristics present in an ancestral organism is altered through natural selection overtime. This is due to different environmental conditions.

What are homologous structures

Similar structures resulting from common ancestry - yet functionally different

What are vestigial structures

Structures that are homologous but have lost heir major ancestral function - structures are reduced in size and non-functional

How does molecular biology support evolution

Species who have similar gene sequences most likely inherited from a common ancestor, showing how speciation occurs from evolution overtime.