B1 - Evolution Flashcards
What are the 2 ways that organisms can be related?
Evolutionary relationships (evolved from the same common ancestor)
Ecological relationships (different species have similar characteristics because they are competing
What is the theory of evolution?
More than 3 billion years ago, life on Earth began as simple organisms from which all the more complex organisms evolved
What are evolutionary trees?
Diagrams similar to family trees that show how different species have evolved from common ancestors
Describe Darwin’s theory of natural selection
Individuals within a species show variation because of differences in their genes
Individuals with characteristics that make them better adapted to their environment have a better chance of survival so they are more likely to breed successfully
This means that the advantageous characteristics are more likely to be passed on to offspring so a species will gradually evolve
What is a mutation?
A change in an organism’s DNA
How do mutations affect natural selection?
If an individual has a mutation that makes them better adapted to survive in their environment (doesn’t always happen), they are more likely to survive, breed and pass on the characteristic that the mutation caused
What were the 3 reasons that many people didn’t believe Darwin’s theory at the time?
It went against religious beliefs because his theory gave an explanation that didn’t need a “creator”
He didn’t know about genes and mutations so he couldn’t explain why new characteristics appeared or how they were passed on to offspring
There wasn’t enough evidence to convince many scientists because not many studies had taken place that supported his theory
What was Lamarck’s theory of evolution?
If a characteristic was used a lot by an organism, it would become more developed through its lifetime
This would then be passed on to the next generation
What were the 2 reasons that Darwin’s theory was accepted more than Lamarck’s theory as time went on?
There is now much more evidence that completely supports Darwin’s theory
Lamarck’s theory was rejected because if you dye a hamster’s fur pink and then it has offspring, its offspring won’t have pink fur
