Adaption, Natural Selection And The Evolution Of A New Species Flashcards
What is a mutation ?
A random change to DNA
State 3 factors that can increase the chance of mutations
Radiation
Chemicals
High Temperatures
State the 3 potential effects of mutations
Advantageous
Disadvantageous
Neutral
Define variation
The difference that exists within populations of living organisms
Why is variation important ?
It allows organisms to adapt to changing environmental conditions
Why does natural selection occur ?
Species produce more offspring than the environment can sustain
Describe natural selection
Variation exists. An organism that is best adapted to the environment will survive, reproduce and pass on its favourable genes that give a selective advantage. This occurs over several generations.
What is an adaption ?
An inherited characteristic that helps an organism to survive
Describe some adaptions of a polar bear
Thick fur White fur Big teeth Sharp claws Small ears
What words describes the formation of a new species ?
Speciation
What is the first stage in speciation ?
Isolating the initial population with an isolating barrier
Name three types of isolation barriers
Geographical
Reproductive
Ecological
Describe the second stage of speciation
Different mutations occur in the two sub populations
What is the third stage of speciation ?
Natural selection occurs. This is different in each sub population due to different selection pressures.
How can you tell that speciation has been achieved ?
Organisms from the two sub populations will not be able to interbreed to produce fertile young.
