Darwin’s Theory of Evolution

CHAPTER 16

Darwin’s Theory of Evolution

Darwin’s observations from this trip lead to the theory of _____________.

Evolution: _________________________________

Process by which today’s organisms have _____________ from ancient organisms.

During his 5 year journey:

Collected __________ and ____________ specimens Took detailed notes of new plants and animals he observed

Darwin noticed specifically the different types of tortoises and finches that he found on different islands.

The strange plants and animals of the Galápagos Islands puzzled Darwin.

Many birds, plants, insects, and reptiles on the Galápagos _____________ South American species, but were ____________ _____________.

TortoisesDarwin saw that each tortoise inhabited a

____________ island.The townspeople could tell which island a tortoise

came from by the _________ of its ___________. On islands with humid highlands, the tortoises are:

____________________ ____________________ ____________________

On islands with dry lowlands, the tortoises are: ____________________ ____________________ ____________________

Finches

As Darwin traveled from island to island in the Galapagos Islands, he noticed that the birds that lived on each island looked ____________ but had ___________________________________.

Darwin began to wonder if species from the mainland had reached the Galápagos, and then __________ —as they ___________ to this new ________________.

He discovered 3 patterns of biological diversity:

Species vary around the world Species vary locally Species vary over time.

Pattern of diversity

Theory Example

Species vary around the world

_________ species __________ each other. They living in different parts of the world

Rhea and the Ostrich

Both _______ ________ living in grasslands

Species vary locally

_______ species in the ______ habitat, ________ in their appearance.

____________ & ____________

Species vary over time

________ that look like ________ organismsFrom different periods of time

____________

_____________The evidence that Darwin

had gathered during his trip suggested that species _______ over ________ by some natural process.

Jean-Baptiste Lamarck

Suggested that all organisms want to improve themselves. (acquired traits) Giraffes could stretch everyday to acquire a longer neck.

The acquired traits of the parents are passed on to the children A giraffe’s longer neck could be passed to offspring.

This was the reason species changed and improved over time.

Jean-Baptiste Lamarck

Suggested that all organisms want to improve themselves. (_________________) Giraffes could stretch everyday to acquire a longer

neck. The acquired traits of the parents are

_________ on to the __________ A giraffe’s longer neck could be passed to offspring.

This was the reason species changed and improved over time.

16.3 Darwin’s theory of Evolution by natural selection

Darwin published his first book on evolution -______________________________

In this book, he explained the 3 parts to evolution. ______________ for existence ________________________ ________________________

Struggle for Existence Organisms produce

______ offspring than can ____________.

Organisms must compete for: ___________ Water living space ____________

Those that ________, will _________ survive.

FinchesThey have __________ to allow for specialized

____________ most finches. crushing beaks grasping beaks probing beaks

The specialization developed allowing the birds to ___________ during the dry season and drought when little food is available.

These specialized tools allow the birds to better compete for food sources with other birds and animals.