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1/10/14 Warm Up Turn in your Toothpick Fish Lab’s to the basket when your warm-up is complete.

1. Which fish colors were advantageous (survived) during the first 4 generations? Why was this?

2. Why did the green alleles disappear from the gene pool after the natural disaster?

The Theory of Evolution

Science happens within a culture

TINTORETTO The Creation of the Animals 1550

Then along comes Darwin…

1831-1836 22 years old!

Warbler finch

Woodpecker finch

Small insectivorous

tree finch

Large

insectivorous

tree finch

Vegetarian

tree finch

Cactus finch

Sharp-beaked finch

Small ground

finch

Medium

ground finch

Large

ground finch

Insect eaters

Bud eater

Seed eaters

Cactus

eater

Then along comes Darwin…

Ancestral species

Descendant species

& those dang finches!

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What Darwin Saw Observations Questions

Many beetle species Why so many?

Plants/animals well suited to environment. Why? How?

Many ways to survive and reproduce. Was there a process that led to this variety?

Grasslands on different continents had different animals. Why?

No rabbits in Australia Why?

No kangaroos in England? Why?

Fossils resembled organisms still alive. How are they related?

Some fossils looked different than living organisms Why did they disappear?

Tortoises in Galapagos varied depending on island they were from.

Why/How were they so well suited?

Finches in Galapagos varied depending on island they were from.

Why/How were they so well suited?

Different climates on different islands. How did this affect life there?

Different beaks on birds depending on their food. How did this happen?

Plants and animals varied noticeably on different Galapagos islands.

Were they once members of the same species?

Video Clip #2

Glyptodont fossils

Modern armadillos Modern sloth

Sloth fossils

Why should extinct species & living species

be found on the same continent?

Darwin’s Work Darwin collected many insects, plants,

and small animals

He would make detailed notes about their behavior, then preserve them and observe their physical features

He sent all his specimens and notes back to England

Darwin’s Influences 1. Thomas Malthus – wrote about population growth

in London

Darwin noticed more animals were born than could survive

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2. Charles Lyell – said Earth was very old due to rate of geological processes

To Darwin, this meant there was enough time for organisms to change and branch out.

3. Farmers and Breeders

Ex. Dog varieties

Artificial Selection – humans breeding plants and animals with the characteristics they want.

Darwin’s reasoning He thought…

The struggle to survive causes only the most “fit” genes to be passed on to the next generation (struggle for existence). Only the best-fit individuals survive and get to pass on their traits to offspring.

Darwin’s Reasoning He thought….

Evolution occurs as advantageous traits accumulate in a population. The frequency of an allele within a population changes.

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Publishing His Research Alfred Russel Wallace – developed his own ideas

on species formation

“On the Origin of Species” – 1859, Charles Darwin

2 Ideas:

1. Descent with Modification

Plants/animals change

LOTS of time

Extinction

Environments change

2. Natural Selection

Variation

Time

Advantage/Selection