Evolution of species Flashcards
What is a mutation
a random change to genetic material
What environmental factors increase the rate of mutation
Radiation
Chemicals
What are the series of events for evolution
Species produce more offspring than the environment can sustain
there is variation amongst offspring
tehre is a selection pressure eg disease, lack of food
in a population only the organisms with the selective advantage survive to reproduce and pass on the favourable alleles to their offspring
these alleles increase in frequency within the population
evolution can result in speciation
What is speciation
the formation of new species
What are the three types of isolation barriers
Geographical
ecological
behavioural
What si the series of events of speciation
A population becomes isolated by an isolation barrier
different selection pressure occur in each sub population
different mutations in each sub population are favoured by the natural selection
each sub population evolves differently, and they become so genetically different
they are two different species
Mutations are the only source of new alleles, giving rise to variation within the population. Explain why variation is important for the survival of a population.
Allows populations to adapt to changing environemtnal conditions
What can cause variation
mutation
What is the role of a mutation in evolution
Provides a new source of alleles
What is adaptation
an adaptation is an inherited characteristic that makes an organism well suited to survival in its environment/niche
Mutations are the only source of new alleles
Explain why it is important that new alleles arise in a species
Allows the species to adapt to changing environmental conditions
Describe the types of isolation barriers involved in speciation
Barriers prevent flow of genes between populations
Geographic barriers are physical like oceans
Ecological barriers are habitat preferences
Behavioural barriers is involved in reproduction
