Unit 7 Flashcards
Differential Reproduction
more fit individuals reproduce more
Artificial Selection
NOT natural: humans selecting for a trait to benefit them
Gene Flow
migration of organisms into or out of the population
Genetic Drift
Random Chance that particular genes disappear (only in small populations)
Founder Effect (genetic drift)
reduction in variation that occurs when a small group of individuals becomes separated from a larger population
Bottleneck Effect (genetic drift)
the way in which a reduction and subsequent increase in a populations size affects the distribution of genetic variation
Directional Selection
One of the extremes is favored and the population shifts in one direction
Stabilizing Selection
the immediate is favored population shifts away from extremes
Disruptive Selection
the two extremes are favored and the intermediate is selected against
Heterozygous Advantage (natural selection)
heterozygous genotype has an adaptation advantage
keeps the recessive allele in the population
gene pool
collection of alleles in the population
Conditions to maintain equilibrium
- No genetic Drift (large population)
- No gene flow in or out
- No mutation
- Random mating (no sexual selection)
- no natural selection
transitional species
link between ancestors and modern organisms
relative dating
aging fossils based on location in strata
absolute dating
analyzing amount of radioactive isotopes found in fossil
Homologous Structures
body parts with similar structure but different function shows common ancestry
Vestigial Organs
remnants of structures that were functional in ancestral species
Embryological Development
all vertebrates have the same basic pattern of development
allopathic isolation
geographic separation
sympathetic isolation
still live in same area
PRE reproduction barriers
Geographic isolation
Ecological Isolation (different habitats in the same region
Temporal- breeds at different times
Behavioral- different patterns
Mechanical- morphological differences prevent mating
Gametic Isolation- sperm cannot fertilize egg
POST reproductive barriers
Reduces Hybrid Viability- genes impair development
Reduces hybrid fertility- sterile
Hybrid breakdown- hybrids may be strong but offspring are feeble or sterile
Origin of Cells
lipid bubbles -> separate inside from outside -> metabolism & reproduction
origin of genetics
RNA likely first genetic material
