Evidence of Evolution

Four clues support the theory of evolution

1. Fossil Evidence

• Fossils allow scientists to show how species have changed over time.

Fossil of a dinosaur with feathers-an ancestor of modern birds

We can trace animal evolution by looking at how the fossils change.

Types of fossils• Frozen in ice, trapped in amber, petrified,

cast and imprint fossils.

These fossilized human

footprints are 3.5 million years old

What type of rock would most likely have fossils in it?

Why aren’t fossils enough evidence?

Peter Look- we’ve got ancestors! Finally! Proof of Evolution!

Heck, this was back before we even had bodies!

2. Anatomy

• Matching or extra/left over body parts support the idea of common ancestors

2. Anatomy

• Homologous structures – body parts that are the same or similar in different species

2. Anatomy• Vestigial structures –body parts that are

useless or left over from a previous ancestor in which they were useful

• Example: Appendix, tailbones, goose bumps and wisdom teeth.

3. Embryology• Many organisms have similar embryos,

supporting the idea of common ancestors.

http://www.the-scientist.com/?articles.view/articleNo/35052/title/Dinosaur-Embryo-Graveyard/

4. Biochemistry

• Many organisms contain similar sequences (sections) of DNA.

• Small mutations or changes in the DNA eventually lead to the evolution of new species.

Humans and chimps have 96% similar DNA.

Chimps have 48 chromosomes compared to human’s 46.

Chromosome #2 is split into 2 separate

chromosomes in chimps, but when combined, they

look just like our #2

Human Fossil Evidence Found

http://abcnews.go.com/Technology/ardi-fossil-brings-us-closer-common-ancestor-humans/story?id=8716359

Click for a news story on new human fossils found…

Quiz

• What are the four pieces of evidence supporting the theory of evolution?

• Fossils, Anatomy, Embryology, Biochemistry

Quiz• What homologous

structure do humans share with a cat?

• Similar skeletons

Quiz

• Name two vestigial structures that humans have.

• Appendix, body hair, tail bones, goose bumps, ear muscles, wisdom teeth, etc.

Quiz

• What is more closely related: a human and a pig or a human and a fish? Why?

• Human and a pig, we share more homologous structures, more DNA in common, and our embryos are more similar.

Homework

• Use Chapter 6, section 2 (starts on 165) to complete the sentences on your worksheet.