Variation and evolution Flashcards
Why are organisms of the same species similar?
They all have the same genes
Why do organisms of the same species vary? Give example
They have different versions of those genes (alleles) e.g humans all have a gene for blood type but they can have A, B or O alleles
What is an adaptation? Give example
A characteristic that helps an organism to survive and have children e.g polar bears have thick, white fur to stay warm and camouflaged in the snow
What does varying characteristics in a population mean? Give example
That some organisms are better adapted for certain conditions than others e.g polar bears with thicker fur are better adapted to survive in a cold environment than polar bears with thinner fur
What are the slightly different adaptations you get within species coded for by?
Coded for by different alleles
What is evolution?
The gradual change in the characteristics of a population from one generation to the next
What is the theory of evolution?
The theory of evolution is that all organisms evolved from a common ancestor (organism) over millions of years
There’s more than 1 mechanism by which evolution occurs - name one
Natural selection
Do organisms from the same population all vary? Give example
Yes e.g different length of fur
What do organisms compete with each other for?
Food, shelter, water etc.
What happens to organisms with better adaptations? ( and what is this caused by)
What does this then result in? Give example
They are more likely to find food, shelter and water etc., survive and have children (Caused by different alleles)
The passing on of alleles for their better adaptations e.g bears with longer fur will stay warmer and be more likely to survive, so they have kids with longer fur
Over time, what happens to the number of organisms with the better adaptations (alleles)?
It increases
Over time, why does the whole population of organisms evolve?
To have better adaptations (alleles)
