Evolution Flashcards
What is a mutation
Mutations are random and are the only source of new alleles
Name a neutral mutation
Eye colour
How to increase the chance of mutation
UV radiation
X-rays
Cigarette smoke
Define selection pressure
Something in an environment that forces some to be fitter than other
Food
Predication
Disease
Why is there a large number of offspring produced
Competition between a population drives evolution the environment means not all can survive so only the fittest will
Variation
The different alleles in a population (form of a gene) variation means some will be fitter than others
Adaptations
How well adapted an organism is to its environment
Survival of the fittest
Best adapted/ fittest are more likely to reach an age to reproduce
Selected alleles increase in frequency because …
The fittest organisms pass on their alleles to the next generation
What is a species
Organisms that produce fertile offspring
What is speciation
The formation of new and district species in the course of evolution
How does speciation happen
A population gets split into 2 and they evolve to their new environment
What is the population split by
Barriers-
Geographical feature- river
Ecological -ph
Behavioural -location, mating
Define isolation
A population becomes split into 2 by a barrier
Natural selection & selection pressures
Selects different mutations in each group due to different selection pressures (environments)
Each sun population becomes genetically different
