Nat5 Biology Unit Three Life On Earth Key Area 6 Evolution Of Species
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What is a mutation?
A random change to genetic material.
What are the three types of mutations?
Neutral Advantageous Disadvantageous
What is NEUTRAL mutation?
Mutation that has no impact in terms of having an advantage/disadvantage
What is ADVANTAGEOUS mutation?
Mutation that gives that organism an advantage over other individuals
What is DISADVANTAGEOUS mutation?
Mutation that puts that organism at a disadvantage compared to other individuals
New ____ produced by _____ can result in plants and animals becoming better ____ to their environment.
New ALLELES produced by MUTATION can result in plants and animals becoming better ADAPTED to their environment.
Mutations are _____ and are the only source of ____ .
Mutations are SPONTANEOUS and are the only source of NEW ALLELES.
What environmental factors (mutagens) can increase the rate of mutation?
Radiation Some chemicals
What does variation within a population make possible?
It makes it possible for a population to evolve over time in response to environmental conditions
What is an adaptation?
An inherited characteristic that makes an organism wipe,l suited to survival in its environment/niche
What do species often do?
Produce more offspring than the environment can sustain
What are Selection Pressures?
A factor such as predation, lack of food or disease that make some individuals better at surviving to reproduce that others
What happens when there are selection pressures?
Natural Selection or Survival Of The Fittest
The best _____ individuals in a population survive to ____ , passing on the favourable alleles that confer the _____
The best ADAPTED individuals in a population survive to REPRODUCE, passing on the favourable alleles that confer the SELECTIVE ADVANTAGE
When adapted individuals reproduce what happens to their alleles?
They increase in frequency within the population
What is Speciation?
The formation of a new Species
When does Speciation occur?
After a part of a population becomes isolated by an isolation barrier
What are the types of Isolation Barriers?
Geographical - mountains, rivers Ecological - pH, salinity Behavioral - preferred food or mates
What is the result of Isolation Barriers?
○ Different mutations occur in each sub-population. ○ Natural selection selects for different mutations in each group, due to different selection pressures. ○ Each sub-population evolves until they become so genetically different that they are two different species.