Download endosymbiont theory

Endosymbiont Theory
Endosymbiotic Theory
The theory that complex organelles (like mitochondria & chloroplasts) evolved
from mutualistic symbiotic relationships between bacteria
Artificial Selection
When an organism’s mate is chosen for them,
Example- when a farmer breeds his plants and animals for specific traits
Natural Selection
The process by evolution occurs, via the success of populations based on
phenotypes and how well they can survive in their environments
evolution
Change in a population over time
Fossil
Evidence through rock strata, preserved organisms, and differences seen over
millions of years in geological time
Homologous Structure
Structures that have the same embryological origin, but different functions;
examples are the arm bones of humans, birds, and bats
Vestigial Structure
A structure that has decreased size or function; appendix, whale pelvis and leg
bones
Analogous Structure
Structure that have the same function, but are not evolutionarily related; insect
wing and bird wing
Embryo
The beginning stages of an organisms development, after the zygote has formed
Fitness
A measure of the success of an individual based on their phenotype and how
well they can survive in an environment
Mimicry
When one species evolves to resemble another species
Usually one or both are toxic or poisonous
Camouflage
When an organism blends in with its environment
Hardy-Weinberg Principle
A principle, that when all 5 conditions are met, results in no evolution for the
population
1. no gene flow
2. no natural selection
3. random mating
4. large population
5. no mutation
Genetic Drift
A random change in the gene pool
Founder Effect
A random change in a gene pool that happens when a small group leaves a
larger group
Bottleneck Effect
Genetic drift resulting from a drastic reduction in population size, often caused
by a natural disaster
Stabilizing Selection
Natural selection that favors intermediate phenotypes rather than the extreme
phenotypes; example-birthweight
Directional Selection
Natural selection that favors one end of a phenotypic spectrum and acts against
another; example is if light brown snails were once favored, but now dark
brown snails have better success.
Disruptive Selection
Natural selection that favors the extreme phenotypes and selects against the
intermediate phenotypes, process usually results in speciation (creation of 2
new species from one)
Behavioral Isolation
A pre-zygotic barrier that happens when organisms are not attracted sexually to
members of another species due to traits like mating dances or calls
Prezygotic Isolation
Isolation before sex
Temporal isolation
Geographic isolation
Behavioral isolation
Ecological isolation
Postzygotic Isolation
Isolation after sex:
Hybrid sterility
Donkey + Horse = mule (sterile)
Adaptive Radiation
The emergence of many species form one common ancestor; Darwin’s finches
Gradualism
Theory that evolution occurs in small gradual steps over time
Punctuated Equilibrium
Theory that evolution occurs with relatively sudden periods of speciation
followed by long periods of stability
allopatric speciation
Occurs when a population divided by a geographic barrier evolves into two or
more populations unable to interbreed
Sympatric speciation
Occurs when a species evolves into a new species in an area without a
geographic barrier
Convergent Evolution
Unrelated species evolve similar adaptations due to similar environment
Shark & Dolphin
Mara & Rabbit