Gene Flow
What is gene flow?
When genetic material from one population is added to another population
What is the effect of genetic drift?
It can lead to the elimination of alleles from a population
What is another word/phrase for natural selection?
Survival of the fittest
What is evolution?
The change in a population over a long period of time
Short giraffes die because they can't reach food, tall giraffes become more common
Natural selection
Does gene flow increase or decrease genetic differences?
Increase
What is the bottleneck effect?
When something happens that results in a random part of the population surviving
What is natural selection?
How does natural selection contribute to evolution?
Organisms gain adaptations to their environment through survival of the fittest, so beneficial traits are passed on and the species changes as those traits become more common
Birds of one color migrate to a population of different color birds and they mate
Gene flow
Does gene flow occur between existing populations or does it cause a new one to be created?
Existing populations
What is Founder's Effect?
When part of the original population leaves and starts a new population
If the trees the peppered moths live on are dark colored, would dark or light moths be favored?
Dark moths (so they blend in)
How does gene flow contribute to evolution?
By introducing genes to a species, it makes more diversity and changes the population
A tornado came through a population of equally red and blue birds, only 1 red bird and 10 blue birds survived, population became mostly blue afterwards
Bottleneck effect
How can gene flow happen among animals?
Animals may migrate or travel to different populations
How does the bottleneck effect affect genetic diversity?
It decreases it
What are the 4 steps of the theory of natural selection?
1. Overproduction
2. Variation
3. Competition
4. Selection
How does genetic drift contribute to evolution?
The new population has less alleles than the original, so it is different and changed from the original
Two rabbits leave the larger population of rabbits and start a new population in a different area, their traits are the only ones passed down
Founder's effect
How can gene flow happen among plants?
Pollen/seeds could be carried on the wind to different populations, or pollinators may take pollen to different populations
How does Founder's Effect affect genetic diversity?
Decrease
What is disruptive selection?
When both extremes of a trait are selected and moderate traits are selected against
Who studied the evolution occurring in the Galapagos Islands and whose work became a basis for how we understand evolution today?
Charles Darwin
The land floods and over half of a population drowns, the ones that survive pass on only their traits
Bottleneck effect