Chapter 13 - Evolution Flashcards
(28 cards)
What are Darwin’s postulates?
- Individuals vary within a population.
- Some traits are passed down through generations.
- More offspring are produced than can survive.
- Natural selection: the most biologically fit can survive.
What is natural selection?
The idea that in varied populations, some traits might be favoured over others naturally (ex. darker insect colors survive better than lighter ones as they cannot be seen by predators). This causes the natural selection of certain traits over others in a population, as if only those with certain traits survive, it is only those traits that are passed down to furure generations.
What is the difference between selection and evolution?
Selection acts on individuals, while evolution occurs in populations.
What are the components of Darwin’s evidence?
- Adaptation
- Fossils.
- Age of Earth (from Lyell).
- Competition (from Malthus).
- Comparative anatomy
- Heredity.
Explain adaptation, and how Darwin observed it.
Darwin observed adaptation in the turtoises of the Galapagos Islands, where the turtles were different on different islands (they had evolved to adapt to their niches).
These turtoises were also different from mainland turtoises.
Explain how Fossils were used as evidence by Darwin.
Fossils showed that species change over time.
Explain what comparative anatomy is.
Comparative anatomy shows the ressemblance between different species, like in their bones. It shows which species have evolved from recent common ancestors.
What is biological fitness?
Biological fitness means being able to survive, breed, and make fertile offspring. Basically, you need to be able to have grandkids.
You also don’t need to be perfectly adapted, you just need to be better adapted than your competitors.
Explain what Dawin concluded from Malthus’ evidence.
Malthus had observed that populations increase exponentially, while food production increases linearly. Darwin determined that because of this, organisms would be competing for food.
What is adaptive radiation?
When organisms diverge from their ancestor. This creates divergent evolution.
An example is with many vertebrates being derived (and having similar bone structures) to the tetrapod ancestor.
What is structural homology?
Homologous structures that came from the same ancestral structure but were adapted to fit different niches.
What is Genetic Homology?
Genes that are the same in many organisms that share a common ancestor.
An example is the eye gene, which is the same for pretty much every organism that has eyes (except octopuses).
What is developmental homology?
Similar development patterns in related species.
What is convergent evolution?
Unrelated organisms that adapt in a similar way to a similar niche. Examples are many animals from Australia that were separated from the rest of the world when Australia was separated from the rest of the continents. Some of these species evolved to be very similar to mainland mammals. An example is with the marsupial mole and the regular mole.
What is evolutionary conservation?
Evolution building on what came before. For example, giraffes only have 7 neck vertebrae despite their long necks, as their ancestors only had 7 neck vertebrae. Some reptiles and birds have many more.
What are vestigial structures?
They are structures that were useful to ancestors but are no longer useful. Examples are hip bones in whales, appendix, and wisdom teeth in humans.
What is exaptation?
When a vestigial structure ends up being used for another function. An example is with dinosaur feathers that were used for display, but in their descendants: birds, they are used for flight and warmth.
What are polymorphs?
Phenotypic variants.
What are the two ways in which genes can evolve?
Natural selection and genetic mutation or recombination.
What is artificial selection?
When humans select the features they want in animals, breeding them for these phenotypes.
What are the five agents of evolutionary change?
- Mutation
- Gene Flow
- Non-random mating
- Selection
- Small population causing genetic drift.
Which is better for mutation? RNA or DNA?
What are examples of mutation?
RNA, because it is single-stranded. COVID-19 is an RNA virus.
Examples:
Covid-19 mutations.
Sickle cell anemia.
White-eyed flies.
What is gene flow?
Give one example.
An exchange of genetic material between species or between populations.
An example is the coywolf.
What are examples of non-random mating?
Artificial selection, self-fertilization, and sexual selection (peacocks).
