Variation and evolution Flashcards
What are the two types of variation
Genetic and environmental
What’s a gene
The codes inside the cell that controlls how we are made and an organisms characteristics are determined by the genes inherited from their parents
How is genetic variation caused
By the combining of genes from 2 parents
What characteristics are determined only by genes
Eye colour
Inherited disorders
Blood group
What is environmental variation
When the environment that the organism lives and grows in causes differences between members of the same species
What is a mutation
Changes to the sequence of bases in DNA and they can result in a new phenotype leading to natural selection
Who came up with the theory of evolution
Charles Darwin
What is survival of the fittest
Organisms with the most suitable characteristics for the environment would be more successful competitors and are more likely to survive
What did Darwin not know
As to why new characteristics appeared or exactly how individual organisms passed on beneficial adaptations to their offspring
Why do new phenotypic variations arise
Because of genetic variation produced by mutations
What is speciation
When a completely new species is formed
Why do species come extinct
Environment changes too quickly New predator kills them all New disease kills them all Can’t compete with other species for food Catastrophic event happens
Why was Darwin’s theory opposed
Religious beliefs - the creator
Darwin had little knowledge as to why it happened
Not enough evidence to convince scientists
Who was Lamarck
He argued that the changes that an organism acquired during its lifetime will be passed on to its offspring
If a rabbit used its legs to run a lot it’s legs would get longer and the offspring would have longer legs
