Outline 15-3 B: Evidence of Evolution 12/4/2018 Evidence of Evolution

I. Fossils 1. Provides a record of past life 12/4/2018 I. Fossils A. A fossil is the preserved or mineralized remains (bone, tooth, or shell) or imprint of an organism that lived in the past. 1. Provides a record of past life 2. Change over time (evolution) can be seen in the fossil record 3. Fossils found in older rocks are different than those found in newer rocks 4. There are many examples of transitional fossils that show intermediates stages 12/4/2018

B. Fossil Examples of Evolution 12/4/2018 B. Fossil Examples of Evolution 1. Whale Evolution a. Thought to have evolved from 4-legged ungulates (animals with hoofs) b. Many intermediate fossils are known which show the gradual change over time 2. Horse Evolution a.Thought to have evolved from smaller non-hoofed animals 12/4/2018

Whale Evolution 12/4/2018

12/4/2018 Horse Evolution

II. Anatomy & Development 12/4/2018 II. Anatomy & Development A. Comparisons of anatomy (structures) between organisms can reveal similarities even when functions are different 1. Vestigial Organs a. Parts that are reduced in size and have little or no function b. Examples: Wings on flightless birds, miniature leg bones in some whales & snakes, tailbones in humans 12/4/2018

Vestigial Organs 12/4/2018 Tail bones in humans Hip bones in whales

2. Homologous structures 12/4/2018 2. Homologous structures a. Structures that look similar in different organisms but may have different functions b. They form in the same way during embryological development c. Used as evidence for a common ancestor d. Examples:  Forelimbs of vertebrates contain the same kinds of bones 12/4/2018

Homologous Structures 12/4/2018

Homologous Structures 12/4/2018

a. Structures that have similar functions but different structures 12/4/2018 3. Analogous structures a. Structures that have similar functions but different structures b. They do not form in the same way embryologically c. Not taken to be evidence for a common ancestor d. Result of living in similar habitats e. Called convergent evolution f. Examples:  Wings of birds & insects  Shapes of dolphins & sharks  Marsupial forms of other mammals 12/4/2018

Analogous Structures & Convergent Evolution 12/4/2018 Homologous Structures – form from same parts in embryos Analogous Structures - due to similar habitats but composed of different parts

Convergent Evolution of Mammals 12/4/2018

a. The study of organisms as they develop before birth 12/4/2018 4. Embryology a. The study of organisms as they develop before birth b. Evolutionary history can be seen in the development of embryos c. Examples:  Embryos of vertebrates:  Each have a:  tail  buds that become limbs  pharyngeal gill slits 12/4/2018

12/4/2018

Which is Which? Tortoise Chick Rabbit Fish Human Salamander 12/4/2018 Which is Which? Tortoise Chick Rabbit Fish Human Salamander This is a blank box

This is a blank box Which is Which? Tortoise Chick Rabbit Fish Human 12/4/2018 Which is Which? Tortoise Chick Rabbit Fish Human Salamander This is a blank box

12/4/2018 Which is Which? Tortoise Chick Rabbit Fish Human Salamander

III. Geographic Distribution of Living Species 12/4/2018 A. Darwin decided all of the Galapagos finches could have descended from a common ancestor from the mainland 1. Each islands’ birds evolved in different ways due to different habitats B. Species living on different continents had descended from different ancestors. 12/4/2018

12/4/2018 C. Animals on different continents could be exposed to similar ecological conditions & evolve in similar ways 1. Thus, animals that were different from each other initially could evolve certain features in common 12/4/2018

Biogeography 12/4/2018 Different animals evolve in similar ways due to similar habitats

IV. Biological Molecules as Evidence 12/4/2018 IV. Biological Molecules as Evidence A. Proteins 1. Comparisons of amino acid sequences of proteins common to many species shows a pattern: a. Species that share a more recent common ancestor have fewer amino acid differences b. Those more distantly related have more changes 12/4/2018

1. DNA changes cause changes in amino acids 12/4/2018 B. Nucleic Acids 1. DNA changes cause changes in amino acids 2. Can compare the nucleotide sequences of species and count number of changes 3. More changes are taken to indicate that species diverged from each other longer ago 4. Scientists create phylogenetic trees from these data 12/4/2018

Phylogenetic tree 12/4/2018