variation and evolution - darwin and natural selection

Question 1

what lead to Darwin wondering how variety of plants and animals developed?

Answer 1

in 1800s, he went on en expedition around the world. he collected vast number of different animals and plants. he was fascinated

Question 2

what did darwin study?

Answer 2

geology and fossils. fossils showed many species of animals and plants today are similar to extinct species

Question 3

what did Darwin come up?

Answer 3

his theory of evolution by natural selection

Question 4

what is Darwin’s theory?

Answer 4

• within a species, we see a wide range of genetic variation for any characteristic
• individuals with characteristics most suited to the environment are more likely to survive to breed successfully
• the characteristics enabling these species to survive are passed on to their offspring (advantageous alleles)

Question 5

when and what did Darwin publish his theory in?

Answer 5

1859 in a book called On the Origins of Species

Question 6

did many people believe Darwin’s theory? why?

Answer 6

it was controversial and was only gradually accepted because at the time people strongly believed God made all the plants and animals that live on earth. Darwin’s theory challenged this. Also at the time many scientists felt that Darwin didn’t have enough evidence to back up his theory. Thirdly, people didn’t understand how characteristics were inherited. Genetics was not understood at the time.

Question 7

who was Jean-Baptiste Lamarck? what was his theory?

Answer 7

• came up with his own theory of evolution
• he suggested when a characteristic is regularly used, it becomes more developed. this strengthened characteristic is then passed onto offspring

Question 8

problem with Lamarck’s theory?

Answer 8

we now know that changes occur in an organism’s lifetime cannot be passed onto offspring. his theory were incorrect and Darwin’s theory is accepted today