Unit 7: Evidence

for Evolution

(1) Types of Evidence…

• Fossil Records

• Comparative Anatomy

• Biogeography

• Carbon dating and chemical composition

• Embryology

• DNA / Genetics

WHALE VIDEO

FOSSIL VIDEO

(2) Comparative Anatomy

• By looking at fossils scientists can:– Identify species which are extinct.– Understand how and when certain anatomical

features developed, and in which types of environments.

• Scientists can look at the skeletal structure of different types of animals and…– Look at similarities in body part development,

position and structure.– Look at differences and consider causes.

(3) Types of Body Structures

• Homologous Structures Features in the body part that are similar between different types of animals, because they all evolved over time from one common ancestor.

• Analogous Structures Features in the body part that are similar between different types of animals, because they evolved in similar environments.

• Vestigial Structures Features in the body part, found between different animals, but no longer have functions. (Proving a connection to a common ancestor.)

http://www.xkgfs.com/images/vestigial-structures-in-evolution.jpg

(4) Phylogenetic Trees

• A diagram used to show the evolutionary relationships between different organisms.

• Also Includes:– The common ancestor.– The order organisms evolved in.

• Based off of Evidence:– Fossils + Comparative Anatomy– DNA– Geology

(5) Common Ancestor

• The organism by which all other organisms evolved from.

• The most primitive ancestor for that type of organism.

(6) Phylo Tree Parts

• Bottom / Base = Oldest Organism/s

• Top = Most recently evolved organisms

• Organisms after a trait:– Evolved after that trait existed in populations.– Contain those traits.

• Organisms before a trait:– Evolved before that trait existed in populations.– Do NOT contain those traits.

(7) Example

1

2 3 4 5 6

Multicellular

GillsLungs

Wings

Live Birth

LimbsFins

EggsOn 4 On 2