Evolution is considered two things by scientists. What are they?
A process and a theory
Fitness
The ability to survive and reproduce
Species
potential to produce viable, fertile offspring
mutations
increase genetic variation; can be beneficial or destructive depending on the environment
What do an organism's structure and function reflect?
Its adaptations to the environment
Autotrophs
acquire energy through sunlight
heterotrophs
acquire energy by consuming other organisms
Natural selection
differential survival and reproduction rates of individuals in a population, often driven by the environment; natural selection acts on any trait that affects survival, including predation, physiology, and sexual traits
Adaptation
heritable trait that develops in response to environmental conditions
Predation selection
acts on predators/prey; selection based on behaviors, habits, and defenses (physical & chemical)
Physiological selection
selection that acts on body functions, such as disease resistance, physiology efficiency, and biochemical versatility
Sexual selection
acts on reproductive success by selecting for traits that make an organism more attractive to its mate, more successful in rearing offspring, or more fertile
What year did Darwin take his 5 year journey on the HMS Beagle?
1831
What observations lead Darwin to the conclusion that natural selection was a thing?
offspring resemble their parents, but are not identical to them; slight variations affect chances of surviving, producing offspring
What were the two propositions Darwin's theory of evolutionary change was based on?
Species change over time; natural selection produces the change
Who's the father of taxonomy?
Linnaeus
What do population members have to have to possess heritable genetic variation
heritable genetic variation
Gene pool
sum of alleles in a population, represents the total genetic variation of a population
What are the assumptions that must be met for the Hardy-Weinberg principle to be true?
#NAME?
What is hardy-weinberg equilibrium
null hypothesis that genes do not change
Five agents of evolutionary change:
#NAME?
What is the raw material for natural selection?
Variation
gene flow
movement of individuals and the genes in and out of populations
genetic drift
effect of chance events, such as the founder effect and the bottleneck effect
founder effect
when a new population is started by only a few individuals (colonization)
-some rare traits may be at high frequencies, others may be missing
-skewed gene pool
bottleneck effect
occurs when a large population is drastically reduced by a disaster
-loss of variation
-gene pool is narrowed
stabilizing selection
reduces variation, but does not change the mean
directional selection
individuals at one extreme become more successful
disruptive selection
individuals at either extreme are more successful than the average
cline
gradual change in phenotypic traits over geographic space
Ecotype
population adapted to unique (often abrupt) local environment
yarrow
altitude
How do new species originate?
populations become isolated, and begin evolving independently
allopatric isolation
other country"
geographic separation
sympatric isolation
same country"
still live in the same area
temporal isolation
different breeding times prevents genes from mixing
behavioral isolation
unique mating rituals, such as courtship and mating calls
mechanical isolation
physical differences such as shape or location of sex organs
prezygotic reproductive isolation
blocks fertilization fro occuring
postzygotic reproductive isolation
prevent viable fertile adult offspring from
3 possible outcomes of hybrid zones
1. Reinforcement- speciation reinforced
2. Fusion- 2 species come back together as one species
3. Stability- hybrid zone persists
What are the two models of speciation?
1. Punctuated pattern- speciation happens with major disruptions
2. Gradual pattern- small, incremental day-to-day changes accumulate
vestigial genes
functional in one, nonfunctional in another
How long ago did homo sapiens diverge from modern apes?
5-8 mya
What animals are considered part of the great apes?
orangutans, gorillas, chimpanzees, bonobos, and humans
Homo habilis
-earliest discovered member of the homo species (2.3 mya)
-used some simple tools
Homo erectus
tool maker, used fire, hunted
What was the genus and species of Lucy?
Australopithecus afarensis
What are the two groups of homo sapiens?
#NAME?