Understanding Evolution: Key Factors Influencing Change Flashcards
why understanding evolution is important for us today?
Evolution is important because it explains how life developed on Earth & how different species are connected.
natural selections (3)
survival of the fittest
genetic variation
environmental influence
Organisms best adapted to their environment survive & reproduce
Survival of the Fittest
Differences among individuals affect survival
genetic variation
Changes in environment select for organisms with beneficial traits
environmental influence
Genetic Mutations (3)
random changes
impact on evolution
mutation rate
occur by chance & can introduce new traits
random changes
beneficial mutations can lead to new adaptations
impact on evolution
influences speed of evolutionary change
mutation rate
genetic drifts (4)
random fluctuations
small populations
bottleneck effect
founder effect
Changes in allele frequencies due to chance
random fluctuations
More susceptible to genetic drift
small populations
A drastic reduction in population size can lead to genetic drift
bottleneck effect
When a new colony is started by a few members of original population
founder effect
gene flow (3)
movement of genes
mixing of populations
prevents speciation
By homogenizing gene pool of separate populations.
prevents speciation
Leads to increased genetic diversity
mixing of populations
Occurs when individuals migrate between populations
movement of genes
sexual selection (3)
mate choice
sexual dimorphism
impact on evolution
Organisms select mates based on certain traits
mate choice
Differences in appearance between male & females
sexual dimorphism
Traits that improve mating success become more common
impact on evolution
artificial selection (3)
human influence
domestication
generic consequences
Selective breeding to enhance desired traits in plants, animals
human influence
Many species been shaped by artificial selection
domestication
Can lead to reduced genetic diversity
genetic consequences
coevolution (3)
predator-prey relationships
mutualistic relationships
interdependent evolution
Species evolve in response to each other
ex: plant-pollinator, ant-plant, host-parasite
interdependent
Can drive evolution of defensive/offensive traits
predator-prey
cheetahs & gazelles, monarch butterflies & bird, lion & zebra, bear & fish, fox & rabbit, garter snakes & rough-skinned newt
predator prey
Both species benefit & influence each other’s evolution.
ex: flowering plants & pollinators
mutualistic relationships
coevolutionary relationship in nature
predator-prey and host-parasite relationships
speciation (4)
formation of new species
allopatric speciation
sympatric speciation
adaptive speciation
When populations become reproductively isolated
formation of new species
Physical barriers divide populations.
allopatric
Species evolve in same geographic area
sympatric
Rapid evolution of many species from a single ancestor
adaptive radiation
