speciation Flashcards
What is a mutation?
A sudden and permanent, random and rare change in the genetic material of an organism
What are somatic mutations?
Occur in non-reproductive cells and are not passed on to offspring
What are gametic mutations?
Occur in reproductive cells eg egg, sperm and can be passed onto offspring
What is gene flow?
The movement of individuals into or out of a defined population
What is microevolution?
A change in allele frequency in the gene pool of a population from generation to generation
What is genetic drift?
The change in allele frequency in a gene pool due to chance
What is the founder effect?
Effect on allele frequencies when only a few individuals colonise a new area and so population is small
What is the bottleneck effect?
Effect on allele frequency when a population decreases in number to become a small population
What is natural selection?
The differential survival and differential reproductive success in individuals whose characteristics are best suited to the environment at a given time
What are analogous structures?
Structures with similar appearance and/or function that have different origins, eg wings of a moth and wings of a bird
What are homologous structures?
Structures derived from a common ancestor that may or may not be used for the same function, eg bat wings and dolphin fins
What is a species?
A group or organisms that can interbreed and reproduce successfully to produce viable, fertile offspring
What is a clade?
A group of species that includes an ancestral species and all of its descendants
What are allopatric populations?
Populations of a species separated by a geographical barrier
What is vicariance?
Splitting of a population into two smaller, isolated populations by a geographical barrier
What is dispersal?
Splitting of a population when some individuals move to a new area
What is speciation?
The formation of two or more species from a single species
What is allopatric speciation?
Speciation involving a period of geographical isolation
What are reproductive isolating mechanisms?
Any barrier (environmental, behavioural, mechanical, physiological) that prevents two individuals of different populations from producing viable, fertile offspring
What are prezygotic reproductive isolating mechanisms?
Mechanisms of isolation before or during fertilization
What is temporal isolation?
Reproductive isolation where two or more species reproduce at different times