7/31/2019 Cornell Notes Ch 7

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Aaron Wong

Pd. 1

Cornell Notes Ch. 7 Section 1

QuestionsWho was Darwin?

What were some

observations?

How many species havebeen discovered on Earth?

What is a fossil?

What did Darwin do on

Galpagos?

What were somedifferences?

What was a difference?

How did the beaks ofGalpagos finches differ

from one island to another?

How many years did he

ponder diversity?

What did he reason?

Headings and NotesDarwins Theory

Darwin was a naturalist who took a trip around theworld on a ship.

Darwins Observations

He observed the organism diversity, remains ofancient organisms, and organism characteristics.

DiversityOver 1.7 million species have been discovered.

FossilsA fossil is the preserved remains or traces of an

organism that lived in the past. Darwin saw many

fossils of animals that were similar, but a lot bigger

than current animals.

Galpagos Organisms

He made many observations, and discovered manyspecies.

Comparisons to South American OrganismsSome differences were: The Galpagos iguanas had

larger claws, while mainland iguanas had smaller ones.

Darwin realized that some species may have comefrom the Galpagos Islands to the mainland.

Comparisons Among the Islands

The tortoises on different islands had differentlyshaped shells.

AdaptationsAn adaptation is a trait that helps an organism survive

in its environment. The finches beaks were suited to

help in obtaining food.

Evolution

He spent 20 years on it.

Darwins Reasoning

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What is one example ofthis?

What is it?

What is overproduction?

What are variations?

Is competition usually

direct or indirect?

What did Darwin propose?

How do they affect

survival?

What causes variation?

He reasoned that organisms on the Galpagos Islands

faced different environmental factors than the ones onthe mainland. In this way, they changed and became

better adapted to their environments. This is called

evolution. Darwins idea was a scientific theory.

Selective Breeding

English farmers in Darwins time used selectivebreeding to produce sheep with fine wool.

Natural Selection

In natural selection, organisms that are better adaptedto their environment are more likely to survive and

reproduce.

Overproduction

Female insects can lay thousands of eggs because notmany of them will survive. This is overproduction.

Variations

A difference in a certain species is a variation.

Competition

Competition is usually indirect.

Selection

Over a long time, natural selection will lead to change.

Helpful variations will accumulate, and unfavorableones will disappear.

Environmental FactorsThey can cause certain species to not be able to live in

a certain area.

Genes and Natural SelectionMutation and the shuffling of alleles can both cause

variation in a species.

Summary: Organisms will adapt to their environments

by natural selection. This adaptation allows them to

survive without as much trouble, and this was provenby Charles Darwin. He observed this on the Galpagos

Islands.