Exam 1 Flashcards
4 ways of looking at species/behavior? (Causations)
- Ultimate Causation
- Proximate Causation
- Ontogenetic Causation
- Phylogenetic Causation
What is ultimate causation? Give an example
•the big picture, the true “why?”
•survival, costs/benefits
Ex. Flamingos are pink because the pinkest flamingos are more desired sexually
What is proximate causation? Give an example
•the “how”
•senses, hormones, neural
•visual trigger to do something
Ex. Flamingos are pink because of their shrimp diet
What is ontogenetic causation? Give an example
•developmental
Ex. Baby flamingos start white when they are born and turn pink as they grow.
What is phylogenetic causation? Give an example
•evolutionary history
Ex. Flamingos are always pink and never blue or green
What is the difference between proximate causation and ultimate causation?
Proximate causation is more physiological based than ultimate causation. Proximate causation explains the “how” rather than the “why”
What is group selection?
The idea that organisms do things for the benefit of their own species
Ex. A fox doesn’t eat all the squirrels to save some for the rest of his species in the area.
What is the exact definition of evolution and what is the cause of it?
Evolution: a change in the gene/allele frequency in a population through time
Cause: natural selection
What is the difference between deduction and induction?
Deduction: use of logic
•all cats have four legs. If I have a cat, it has four legs.
Induction: use of example to prove
•if all cats have four legs, I will look at several cats in an effort to prove that fact wrong
What is the 5 step argument for evolution by natural selection
- Variation
- Inheritance
- Excess reproduction
- Differential survival
- Evolution
Explain variance (step 1) in the 5 step argument for evolution
Individuals in a population differ in characteristics
•such as their morphology (shape, physical characteristics, size)
•behavior
•effect an organisms ability to do and not do certain things
Explain inheritance (step 2) in the 5 step argument for evolution by natural selection
On average, an offspring tend to resemble their parents
Explain excess reproduction (step 3) in the 5 step argument for evolution by natural selection
Organisms are capable of producing far more offspring than can survive in a world of finite resources, creating competition
•Darwin’s “struggle for existence”
•Thomas Malthus “on populations”
Explain differential survival (step 4) in the 5 step argument for evolution by natural selection
Because of the differences between individuals and because of competition, some individuals will leave more offspring than others
Explain evolution (step 5) in the 5 step argument for evolution by natural selection
Because of differential survival and inheritance, throigh time, there will be a change in the gene/allele frequency in the population
What are the three directions of selection?
- Directional selection
- Stabilizing selection
- Disruptive selection
What is directional selection?
One extreme is favored, the other extreme is favored against
What is stabilizing selection?
Both extremes are selected against, the middle selection is favored
Disruptive selection
Both extremes are favored, middle expression is selected against
What is tradeoff?
Something that has its costs and benefits
Ex. Having a long neck as a giraffe has many costs and benefits
What is adaptation?
A solution to a problem in nature (giraffes long neck is an adaptation to be able to eat)
