Natural Selection Pt1 Flashcards
What is evolution?
Genetic change in a population over time.
What is natural selection?
Process where individuals with advantageous traits survive.
What is adaptation?
Trait that enhances survival and reproduction.
Who thought of the great chain of being?
Aristotle
Linear organization of species by complexity.
What are fixed types?
Species believed to be unchanging over time.
Who is Georges-Louis Leclerc?
Naturalist who proposed life could transform.
Who is Jean-Baptiste Lamarck?
Species aren’t fixed; they change over time.
Two processes: use and disuse of body parts, inheritance of characteristics.
What is inheritance of acquired characteristics?
Traits gained during life passed to offspring.
Who is Charles Darwin?
Naturalist who developed theory of evolution.
What is HMS Beagle?
Ship on which Darwin made significant observations.
What are the Galapagos Islands?
Location of Darwin’s key evolutionary observations.
What are endemic species?
Species found only in a specific location.
What is variation?
Differences among individuals in a population.
What is heritable variation?
Genetically based differences passed to offspring.
What is fitness?
Lifetime number of progeny an individual produces.
What is selection?
Process favoring individuals with advantageous traits.
What are the types of adaptations?
Structural, behavioral, and physiological adaptations exist.
What is structural adaptation?
Physical traits that enhance survival.
Example: duck’s webbed feet.
What is behavioral adaptation?
Actions that improve survival and reproduction.
Example: migration or hibernation.
What is physiological adaptation?
Internal body processes aiding survival.
Example: snake venom or antifreeze proteins.
What is competition?
Struggle among individuals for limited resources.
What are the constraints of natural selection?
Adaptations are compromises, not perfect solutions.
Example: even though the 1st bunny can get more food, it has more predators, therefore bunny (though gets less food) has no enemies and lives longer.
Who is Alfred Russell Wallace?
Co-developed theory of evolution by natural selection.
What are the evolutionary steps by natural selection?
Observations: competition (limited resources), variation (some better at competing than others), heritable traits (some differences in ability to compete must be heritable) lead to: selection (winner or loser, better survival = higher fitness/reproduction), adaptation (change in body size due to evolution).
What did Darwin observe?
Noted variation and similarities among Galapagos species.
What did Georges-Louis Leclerc believe?
Earth was formed according to laws of physics and chemistry; life could transform when environmental conditions changed.
Example: fossils are important evidence of change.
What was the purpose of the Beagle voyage?
To map the coast of South America and observe similarities in species.
What are the three necessary conditions for evolution via natural selection?
- Must be variation in the trait. 2. Variation is heritable. 3. Variation has fitness consequences.
Does adaptation mean perfection?
NO! Organisms are adapted to the current environment; natural selection is often constrained.
