Evolution - Principles of Evolution
23 important questions on Evolution - Principles of Evolution
What is artificial selection?
What is natural selection?
What is meant by survival of the fittest and variation? (Darwins theory outline)
- The idea that, in a grander struggle for existence, some individuals will have a greater chance of survival than others
- If you are able to survive a scenario, you would be able to pass down whatever enabled you to survive to the next generation
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What are the Tenants of Natural selection?
- More offspring are produced than can survive
- Traits vary among individuals, leading to different rates of survival and reproduction
- Traits differences are heritable
What happens if there are more offspring of one population than can excist?
You can either:
- Not survive and be eliminated as an individual
- Survive and pass down those characteristics, that made you able to survive, to future offspring -> can gradually lead to new species
Natural selection occurs at the level of 1..... And not on the level of 2.... Or 3....
- An individual
- Species
- Gene
Why is Darwins contribution important?
- His explanation provided a mechanism for generation of new life forms
- This is something that had not happened before
What are the contributions of Wallace?
- Conducted research in the Indian Ocean
- Had a theory very similar to Darwins
- Wrote to Darwin and said he saw/thought that species were in competition
- Conversation with Darwin; said that Darwin had to publish his theory
What did Darwin do in 1871?
What are vestigial structures?
- Physiological structure that can no longer benefit the individual.
- These are still hanging around, because they are neither an advantage or disadvantage for the individual
What is meant by the term fitness?
What are examples of microevolution?
- Mutation
- Selection
- Gene flow
- Genetic drift
What is Sexual selection?
- There is a competition over mates
- There is a struggle between individuals of the same sex in order to mate to pass on genetic material
What are reproductive strategies?
- Reproducing and parenting
- Maximize reproductive succes
- Strategies vary for males and females
What are reproductive strategies for females?
- Primary concern: survival of offspring
- Limiting resource: food
- Result: females are very picky in finding their mate. They want to make sure they pick a high-quality mate that will genetically contribute to their offspring
What are reproductive strategies for males?
- Primary concern: mate often
- Limiting resource: females
- Result: male-male competition
What is intrasexual selection?
- Helps males better compete against each other
- Male-male competition -> intrasexual selection (within the same sex) -> helps males better compete against each other
Do natural and sexual selection always work together?
What is sexual dimorphism?
- Physical differences between sexes of the same species
- Due to intrasexual selection pressure
- Often associated with mating patterns (monogamy, polygamy)
What is genetic drift?
- Effects small populations
- Due to sampling error
- Example:
- Random sample of brown, dark green and light green frogs. For some reason the brown frogs die out -> through the process of genetic drift, you are not going to have those brown frogs anymore
What is the bottleneck effect?
- Genetic reduction due to catastrophic event
- Example:
- You have a mix of red, yellow, blue, green and purple genes in an original population. It undergoes a bottleneck (meaning that there is a catastrophic event) that limits the genes that are able to pass through. Those that survive, in this case the yellow and blue genes, and all the population thereafter will have yellow and blue genes
What is the founder effect?
- Newly isolated subpopulation
- Example:
- A few individuals of a population migrate to someplace. For now reason or another they maintain the same genetic pool as those who founded the population -> they will maintain that lack of genetic diversity
What is gene flow?
- The transfer of genes from one population to another
- Barriers to gene flow
- Mountains, river, religion, socio-economic status etc.
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