Ch.6 Organic Evolution; Part 2 Flashcards
forces that alter allele frequencies in a gene pool
-recurring mutation
-genetic drift
-migration
-natural selection
-interactions of all
Any change in nucleotide sequences that effects survival and reproduction
recurring mutation
mutation is the source of all _____
genetic variability
recurring mutations make impacts on bigger populations that small because __
they are less likely to pass on traits to their offspring
single mutations depend on other forces of evolution to increase its ___
frequency
what is the force that enforces a random fluctuation in allele frequencies from generation to generation due to finite size?
genetic drift
genetic drift primarily damages ___ populations
small
small populations do not contain ____ amounts of variation
large
if a population size remains small for many generations, genetic variation can be ___
depleted
Loss of variability is harmful to evolutionary success because it restricts genetic responses to ____
environmental change
types of genetic drift
-population bottleneck
-founder effect
large reduction in population size leading to the increased significance of every evolutionary change or environmental condition result in the survival of only a few individuals; random
population bottleneck
founder effect: formation of a new _____
geographic location
founder effect may lead to….
new species
force in species that are geographically subdivided; causes movement
migration
migration increases….
genetic variation within the poulation
migration prevents ____ barriers and ___, and different population becoming too genetically distinct
reproductive barriers and speciation
gene flow
movement of alleles
how does natural selection effect species?
it favors that organisms with superior traits
natural selection can change both ___ and ___ frequencies
allelic and genotypic
what are Darwin’s first 3 observations and the inference they led to?
-Observation 1: organisms have great potential fertility
-Observation 2: natural population remain constant in size
-Observation 3: resources are limited
-Inference 1: overpopulations increases competition creatinga struggle for existence- limited resources
* influence of Malthus
Observations 4,5 and inference 2 and 3
-Observation4: populations show phenotypic variation among organisms
-Observation 5: some variation is heritable
-Inference 2: varying organisms show differential survival and reproduction which favors advantageous traits
- Inference 3: natural selection generates adaptations and new species
what are Darwin’s first 3 observations and the inference they led to?
-Observation 1: organisms have great potential fertility
-Observation 2: natural population remains constant in size
-Observation 3: resources are limited
-Inference 1: overpopulations increase competition creating a struggle for existence- limited resources
* influence of Malthus
