Evidence of Evolution

Fossil Record

1. Shows that ancient species are similar to current ones

2. Show some species have remained unchanged for millions of years

3. Darwin predicted the existence of fossil intermediates between species

Fossil Record

Similarities in Structure

1. Homologous Structuresa. Similar features that originated in a

shared ancestor Ex. arm and wing

Similarities in Structure

2. Analogous Structuresa. Structure that serves the same function in 2

species, but is NOT derived from a common

ancestorb. Examples

1. birds’ and insects’ wings2. walking limbs of insects & vertebrates3. cranium of vertebrates & exoskeletal head shield of insects

Analogous Structures

Similarities in Structure

3. Vestigial structuresa. Apparently useless feature that was

useful to an ancestor Ex. snakes w/pelvic & hind limb bones

Comparative Embryology

1. Vertebrate embryos exhibit homologous structures during certain phases of development but become totally different structures in the adult forms

2. Example: many vertebrates embryos look virtually the same early on during development

Comparative Embryology

Comparative Biochemistry

1. Many different organisms share very similar complex metabolic molecules

2. The more closely related the species are, a greater # of amino acid sequences are shared

Biogeography

1. Evolution is closely linked 2/climate & geological forces such as plate tectonics

2. Explains ancestral relationships & geographic distribution seen in fossils & living organisms

Adaptations

A. Fitness: a measure of how well an organism can survive and reproduce in a specific environment

B. Types of Adaptations1. Camouflage2. Mimicry—similarity of one species to

another3. Antimicrobial resistance

Camouflage

Mimicry