Exam 2 Flashcards
What is gene flow? (Hint: What’s a synonym?)
Movement of an individual or genetic material from one population to another (aka Migration) - Important source of genetic variation
What is genetic drift?
A mechanism of evolution in which things evolve by chance
What are some examples of gene flow?
Pollen and people traveling
What is natural selection?
The first proposed mechanism for evolution- dependent on environment and existing heritable variation
How was natural selection discovered?
Discovered by Charles Darwin on the Galapagos Islands - high level of endemism
How does natural selection work?
Limited resources —> organisms w/heritable traits favoring survival and reproduction tend to leave more offspring–> traits increase –> population becomes more adapted to environment overtime
What is evolutionary fitness?
How good a genotype is at leaving offspring in the next generation relative to others (success @ surviving and reproducing)
How does evolutionary fitness affect evolution?
Organisms with highly favored heritable traits pass their genes onto the next generation
What are adaptations?
Features that arose and were favored by natural selection based on function that help organisms survive and reproduce
Does a trait always stay adaptive?
No, things like vestigial structures show that not all past traits are adaptive now
What kind of adaptations exist?
Behavioral - allows for better evasion of predators
Anatomical - feature giving organisms access to valuable new resources
Protein - functioning better @ body temp (?)
What is “Survival of the Fit Enough” more accurate than “Survival of the fittest”?
Survival of the fittest implies biggest and toughest survive to pass genes while survival of fit enough implies that organisms that live long enough to pass on genes
What is sexual selection?
A mechanism for evolution that takes two forms
Intersexual selection (mate chooses mate of other sex)
Intrasexual (mates compete w/ members of same-sex or opposite sex)
How does sexual selection influence evolution?
Sexual dimorphism - differences/clear distinction between sexes of a species
What is artificial selection?
A mechanism of evolution where people select organisms to reproduce
How have humans leveraged inheritance long before the mechanisms of evolution were discovered?
Farmers and breeders allow only plants and animals with desirable traits to reproduce (think about fruit in grocery store)
What is coevolution?
two or more species reciprocally affect each other’s evolution/have close ecological relations (ex, prey, and predator)
Why ?
answer later
When do we see organisms coevolve?
Two main examples
Competition (through share similar niches)
Mutualism (helping one another like bees and flower)
How are organisms, population, and ecosystems related?
Organisms tend to live in populations with in ecosystems
What are biotic factors in an ecosystem?
Living factors (fungi, plants, animals, bacteria)
What are abiotic factors in an ecosystem?
Non-living factors (air, minerals, water, sunlight)
How do biotic and abiotic factors influence each other?
They act as selective pressures and drive evolution (check)
What are selective pressures?
Evolutionary forces that favor a certain phenotype in a certain environment
How do selective pressures affect the evolution of populations?
They drive evolution through natural selection
What is a niche?
A specific role that a species plays
How do niches relate to evolution?
Niches are developed through evolution based on a species phenotype, type of food it eats, relations w/other species, where it lives, reproduces
