Evolution Flashcards
(13 cards)
How can changes to alleles be present in a population?
- new alleles forming as result of;
1. mutations
2. being introduced to a population through migration
What is a gene pool
Combination of the genes present in a population
What are the barriers to gene flow?
- Geographical barriers such as oceans, mountain ranges, deserts.
- Sociocultural barriers such as economic status, educational background, social position
What is gene flow?
The movement of genetic material from one population to another.
What are the three observations that Darwin’s theory of natural selection is based on?
- Variation
- Birth rate
- Nature’s balance
What are the six steps to natural selection?
- Variation
- Overproduction
- Struggle for existence
- Survival of the fittest
- Reproduction
- Generational change
What is a selective agent?
Environmental factors acting on a population
What is genetic drift?
The random, nondirectional change in allele frequency between generations.
It is determined by chance
What is the founder effect?
Small group moves away from its homeland to a new area.
Establishes a population which later expands.
What does the founder effect cause?
A different allele frequency from the original population.
A decreased genetic population.
What is a species
A group of individuals that share many characteristics.
Are able to interbreed under a natural conditions.
Produce fertile offsprings
What is speciation? (5)
Two populations are isolated for a long time.
Environmental influences on each are different.
Major changes in allele frequencies within the populations occur.
Members of the populations become very different.
Interbedding is no longer possible.
The two populations are now considered as separate species.
