B1.7 Evolution Flashcards
Define evolution
The adaptations species encounter over millions of years by he survival of the fittest
Who was Lamarck and what was his theory?
He was a French biologist who thought all organisms were linked by the ‘Fountain of Life’. He thought individual animals adapted and evolved to suit their environment. He thought every type of animal evolved from a primitive worm. Eg. A giraffe had to stretch to reach the leaves so that giraffes offspring would have a longer neck because the parents stretched their neck muscles.
Who was Charles Darwin?
Lamarck influenced Darwin but Darwin didn’t think the fountain of life was correct so he set out on a voyage in 1831 to South America on the Galápagos Islands and he recognised a huge variety of species. He studied how different animals have adapted differently on their island and spent 20 years studying his results. He came up with the theory of evolution.
What’s survival of the fittest?
Reproduction always gives more offspring than the environment can support. Only those that have inherited features most suited to their environment , the fittest will survive. When the fittest of the offspring breeds they pass on the genes with the useful characteristics
What evidence did Darwin provide for the theory of evolution?
He used plants and animals from his South America voyage as evidence. Darwin carried out breeding experiments with pigeons at his home because he wanted to show that features could be artificially selected. Darwin also studied different types of barnacles
Why did people object to Darwin’s ideas?
It challenged the belief in God because Christians beloved God created all organisms. Many scientists felt there was not enough evidence. Also there was no way to explain inheritance and variety because genes weren’t discovered yet.
What was Darwin’s book called and when was it released?
1859
It’s called, “On the Origin of Species by means of Natural Selection”
What’s natural selection?
The individual organisms in any species show lots of variation due to the genes they inherit. Only the offspring with the genes best suited will survive and breed successfully. Eg. Rabbits have inherited good eyesight and long legs to escape from foxes.
What are mutations?
Tiny changes in long strands of DNA. They occur quite naturally through mistakes when the cells divide.
How can mutations be good?
They introduce more variety and can cause an adaptation that makes the organism better suited to the environment and this will be passed onto the next generation
What’s an evolutionary tree?
Model of the evolutionary relationship between different organisms based on their appearance and increasingly on DNA evidence
How are evolutionary trees useful to us?
They help us see what species adapted from each other and we can infer similarities and differences between species to determine how they have adapted differently
