Charles Darwin
Scientist who observed organisms (living and fossilized) in many global locations, and developed the Evolutionary theory. Published "Origin of Species
Russell Wallace
Scientist who observed living organisms in global locations. Developed Evolutionary theory at the same time as Darwin by making large collections and detailed drawings of specimens.
Species
A group of organisms that is able to reproduce with each other.
Populations
Groups of individuals of the same species that occupy a given area at the same time and share a common gene pool
common ancestor
Related organisms (living or fossilized) can be traced back to a ____________________
descent with modification
the change in the traits of a population from generation to generation is called
Genetic Variation
Each organism can have different versions of a given gene (alleles).
Random mutation, Sexual reproduction (crossing over and combining genes from two parents)
Sources of genetic variation in populations
Gene Pool
The sum of all the alleles for all traits (pool of hereditary resources for entire population)
inherited traits
traits or characteristics that are passed down from a parent to offspring
acquired traits
traits that are not inherited, but gained during an organisms lifetime (muscle building)
instinct
behaviors that do not require learning, and is passed down to offspring
learned behavior
a behavior an organism gains through experiences during its lifetime, not instinct
Adaptation
A trait that allows a species to be better suited to its environment. Can be either structural or behavioral.
Structural Adaptation
Physical attributes which improve a species ability to live and reproduce. Examples include: hawk's talons, shark's broad tail, toad's long-sticky tongue, clam's hard shell, etc.
camouflage
A structural adapdaptation in which an animal's color or pattern helps an animal blend in with its surroundings
mimicry
A structural adaptation in which an organism can be protected from predators by looking like an object or another animal
Behavioral Adaptations
The actions or activities which improve a species ability to survive and reproduce. Examples include: Migration, Hibernation, Getting Food, Finding/Making Shelter, Defending Self, Raising Young
Migration
Movement of animals from one area to another due to changes in seasons or environment.
hibernation
A long period of rest or inactivity by an animal, usually in the winter, to conserve energy
care for young
The behavioral adaptation of some birds and mammals to nurture their offspring and enhance their rate of survival
Natural Selection
Organisms with traits better-suited to their environment survive and reproduce more often (This causes traits to change over time).
Directional Selection
A pattern of Natural selection in which one phenotypic extreme is at an advantage compared to others of the population (Peppered Moths)
Stabilizing Selection
A pattern of natural selection in which the Intermediate phenotype is favored (Human birth weight)
Disruptive (Diversifying) Selection
A pattern of natural selection in which both extremes are favored - swallow tail butterfly
Genetic Drift
CHANCE events influencing the frequencies of genes in populations.
Speciation
Formation of a new species due to isolation factors
Reproductive Isolation
The situation that occurs when subpopulations of a species are prevented from interbreeding
Geographic isolation
A type of isolation produced by physical barriers - (oceans, mountains, rivers)
Behavioral isolation
A reproductive isolation mechanism in which subpopulations of a species do not mate because of differences in actions and rituals (bird dances)
Temporal isolation
An reproductive isolation mechanism in which subpopulations of a species do not mate because of timing problems (frog breeding seasons)