Flashcards in Test 1 - Questions Deck (45)
Why is logical thinking simple but not always easy?
Because we've evolved to be good at certain types of thinking.
Where do cells come from?
All cells come from pre-existing cells.
Why are observational studies performed?
To look for ways to cellect data that will support or challenge hypotheses, when an experiment can't be done.
What often happens when a species dissapears from the fossil record?
A similar species appears, often in the same geographical area.
How quickly does evolution occur?
Usually very slowly, but there are some kinds of evolution that have been observed on faster scales.
What stands as evidence that different species evolved from the same common ancestor?
- species fall naturally into groups
- geographic patterns of relatedness
Who came up with the first idea of evolution?
What was Lamark most famous for?
Having an incorrect theory about how evolution worked.
How does selection operate?
Selection operates on individuals, individuals are not adapted for the good of the species.
What is an adaptive "trade-off"?
A compromise between conflicting goals... ex. brightly coloured birds are more attractive to mates, and to predators.
What is co-dominance?
When the heterozygous genotype results in a phenotype that displays a combination of both alleles.
Can we ever say that a population is in perfect Hardy-Weinburg Equilibrium?
No, we can only have evidence that a population is not in equilibrium, or that it is close to equilibrium.
When does Hardy-Weinburg Equilibrium occur?
When there is:
- random mating within a closed population
- no diffferences in fitness between genotypes
What happens when a population meets the target for directional selection, and stays the same for a long time?
The population continues to adapt, now as stabilizing selection.
In what size population is drift the strongest?
For what is gene flow an obstacle?
What is the only source of new alleles?
Why do inbred individuals tend to have lower fitness?
- they are more likely to be homozygous for rare genetic defects
- they are less likely to be heterozygous of immune-system genes
- lower survival rate
Why do males tend to have the more striking physical traits than females of their species?
For courtship or the battle for a mate...
Males can maximize fitness by mating as much as possible.
How can females maximize fitness?
By being choosy about mates, since they invest a lot in offspring.
Which method of isolation is adaptively favoured?
Prezygotic, because it is less wasted effort
What is a disadvantage of the morphological species concept?
Some animals may look similar but be unable to mate.
What are some disadvantages of the ecological species concept?
- it's hard to agree on
- not clear how it relates to the idea of "evolutionary units"
What are some advantages of the phylogenetic species concept?
- well defined
- broadly applicable
What are some disadvantages of the phylogenetic species concept?
- hard to estimate phylogenies
- requires a lot more information about populations
Where do new species come from?
How do species split to form different species?
- genetic isolation: because with too much gene flow populations wouldn't diverge
- genetic divergence: change in alleles over time creates a new species
How does divergence by partitioning habitats work?
Animals of the same species may adapt different diets, and if they mate with those of the same diet, the species could diverge.
Why do species diverge when mutation causes genetic incompatibility?
If organisms are in the same place but can't produce fertile offspring, they are reproductively isolated.