Unit 7 Flashcards
Natural Selection
Organisms with better traits survive and reproduce more
Fitness
More fertile and have viable (can survive) offspring leads to higher fitness and reproductive success
Artificial Selection
Humans choose traits (ie. dog breeding)
Genetic Drift
Random changes in allele frequencies (affects small populations more)
Bottleneck Effect
Disaster kills most of population and there are random survivors left
Founder Effect
Small group leaves & starts a new population with different genes
Migration (Gene Flow)
New genes enter or leave a population which causes changes in allele frequencies
Speciation
New species forms when populations can’t interbreed
Small and Large Population
Small is more affected by genetic drift, large has a more stable gene pool
Hardy Weinberg Formula
p (dominant) + q (recessive) = 1; if there is no mutations, no gene flow, no natural selection, and random mating in a large population
Geological Evidence
Fossils in rock layers show changes over time
Geographical Evidence
Where species live
Physical Evidence
Body structures show common ancestry
Biochemical Evidence
Similar DNA and proteins mean closer relation
Mathematical Evidence
Hardy Weinberg and allele frequencies over time
Highly Conserved
Traits and DNA stay the same across many species
Antibiotic Resistance
Bacteria evolve to survive drugs (example of natural selection)
Pesticide Resistance
Insects evolve to survive chemicals
Tumor Cell Resistance
Cancer cells mutate to resist treatment
Vestigial Structures
Leftover structures with no current use (ie. human tailbone)
Phylogenetic Tree
Diagram that shows evolutionary relationships
Cladogram
Simple tree that shows common traits
Outgroup
The most distant and least related group
Most Recent Common Ancestor MRCA
Where two branches meet there is a shared ancestor
