Pig Turtle Chicken Salamander Human Fish A B C D E F

Evolution Scientists have observed that the earth and its organisms have gradually changed over a long period of time. The process of gradual slow change through time is called EVOLUTION.

Evidence supporting Evolution Evolution is supported by the geologic record, fossils, comparative studies in the fields of anatomy, cytology, embryology, and biochemistry.

Theory of Evolution Simple organisms evolved into •Existing life forms evolved from earlier life forms; share a common ancestor. Simple organisms evolved into more complex organisms

Geologic Record A.k.a. Earth’s timeline Earth is about 4-5 billion years old!

Fossil Record Fossils: - direct or indirect remains of organisms preserved in rocks, amber, ice or tar - can indicate how long ago an organism existed Age of a fossil: - determined by carbon dating or by looking at the rock layer

Questions Which layer contains the oldest fossils? Which layer contains the youngest fossils? Which layer contains the most complex fossil? Which layer contains the simplest fossil? If the fossils in layer A resemble the fossils in layer B and C, what does this suggest?

Comparative Anatomy •comparing body parts Homologous– more similar in structure but different in function Analogous– different in structure but similar in function

Q: Which limbs represent homologous structures? Q: Which limbs represent analogous structures?

Comparative Cytology - comparing cell structure/organelles Prokaryote -No nuclear -cell membrane -nuclear membrane -chromosomes membrane - few organelles - cytoplasm - complex organelles Q: What organelles do prokaryotes and eukaryotes share? Eukaryote

Comparative Embryology Comparing embryological development Q: What evidence suggests that all 4 organisms have a common ancestor?

Comparative Biochemistry Comparing the chemistry of living things (proteins, enzymes, hormones, DNA) Human DNA A-G-G-C-A-T-A-A-A-C-C-A-A-C-C-G-A-T-T-A Chimpanzee DNA A-G-G-C-C-C-C-T-T-C-C-A-A-C-C-G-A-T-T-A Gorilla DNA A-G-G-C-C-C-C-T-T-C-C-A-A-C-C-A-G-G-T-A

What do you think is the most important form of evidence for evolution? Comparative Biochemistry (DNA) is most ACCURATE!