notes Flashcards
biological evolution
- Descent with modification
- 1 way to detect evolution is to look for a shift in the gene pool of a population
- Allele frequencies change from one generation to the next when evolution occurs
Microevolution
- Small scale genetic changes within a species
- Over long term
- Microevolutionary changes also explain macroevolutionary events
- Emergence of new species
catastrophism
- Continual remodeling of Earth’s surface
- Some people explained the distribution of rock strata with the idea
Principle of superposition
- Lower rock strata are older than those above
- Suggests an evolutionary sequence for fossils within them
Lamark
1st to purpose a testable mechanism of evolution, but it was based on use and disuse of traits during an organism’s lifetime
survival of the fittest
organisms with highest evolutionary fitness are the ones that have the greatest reproductive success
fitness
an organisms contribution to the next generation’s gene pool
Does evolution occur if a population meets all of Hardy-Weinburgs assumtions?
NO, because allele frequencies do not change from generation to generation
Hardy-Weinberg in real world
conditions for Hardy weinberg equation do not happen in natural populations
Directional Selection
1 extreme phenotype becomes more prevalent in a population
Disruptive selection
Multiple extreme phenotypes survive at the expense of intermediate forms
Stabilizing selection
An intermediate phenotype has an advantage over individuals with extreme phenotypes
Balanced Polymorphism
- Natural selection indefinitely maintains more than two alleles for a gene
- Harmful recessive alleles may remain in a population because of a heterozygous advantage in which carriers have a reproductive advantage over homozygous
sexual dimorphisms
-Differentiate sex
-Result from sexual selection
(lions–males have manes, females don’t)
Sexual selection
Natural selection in which inherited traits, even those that seem nonadaptive, make an individual more likely to mate
