Genetics, populations, evolution and ecosystems Flashcards
All new species arise from what?
- what does this result in?
- what is this represented in
Existing species
- different species sharing a common ancestry
- as represented in phylogenetic classification
what can common ancestry explain?
the similarities between all living organisms
What is are the 4 common chemistry’s in organisms?
- all proteins made from the same 20 or so amino acids
- physiological pathways (anaerobic respiration)
- cell structure
- DNA as genetic material and a universal genetic code
What do individuals of the same species usually share the same of but different combinations of?
share the same genes but usually different combinations of alleles of these genes
An individual inherits what from their parents?
Alleles
A species can exist as one or more what?
Populations
What is their variety of in a population and what is this due to?
phenotypes of organisms
- due to genetic and environmental factors
What two forces affect genetic variation in populations?
- genetic drift
- natural selection
genetic drift causes what in small populations?
changes in allele frequency
when does natural selection occur
When alleles that enhance the fitness of the individuals that carry them rise in frequency
What is evolution?
A change in the allele frequency of a population
What happens if a population becomes isolated from other populations?
hint - gene
There will be no gene flow between the two populations
If there’s no gene flow between populations what can happen?
Leads to an accumulation of genetic differences in the isolated population, compared with other populations
- the differences may lead to the organisms in the isolated population being unable to breed and produce fertile offspring with organisms from other populations
What does the reproduction isolation mean about the species
That a new species has evolved
What do populations of different species live in?
Communities
