15.2 EVIDENCE OF EVOLUTION

I. THEORY OF EVOLUTION

A. Natural Selection is only one part of the theory of evolution.

B. Theory explain natural phenomena based on observations

C. Evolution states that all organisms on Earth have descended from a common ancestor

II. EVIDENCE FOR EVOLUTION

A. Fossil Record 1. Record of species that lived long ago 2. Ancient species are similar to current

ones 3. Some species have remained

unchanged for millions of years

B. Anatomy– physical bodies of current and extinct species may show relationships 1. Homologous structures – Anatomically

similar structures inherited from a common ancestor

2. Analogous Structures- Can be used for a similar purpose but ARE NOT evidence of evolution. a. Similar traits can evolve independently b. bird wings and insect wings

3. Vestigial Structures– structures that are the reduced forms of functional structures in other organisms

C. Comparative Embryology 1. An embryo is an early pre-birth stage of

an organisms development 2. Many vertebrates have similar stages

while in the womb A. Pharyngeal pouches – we have “gills” guess embryo interactive

D. Comparative Biochemistry 1. Similar features in DNA, RNA, amino

acids 2. The more similar the features the more

closely related.

E. Geographic Distribution 1. Species are more closely related to

species close to them geographically 2. Created field of biogeography–

study of the distribution of plants and animals on earth

III. ADAPTATIONS

A. Adaptations Inherited traits Increase FITNESS

Fitness = traits which lead to greater survival and/or reproduction

B. Non-adaptationsNot all features are adaptations

EXAMPLES OF ADAPTATIONS

1. Camouflage– allows species to blend with their environment

2.Mimicry- one species evolves to resemble another one

3. Antimicrobial resistance— Bacteria have adapted to be resistant to antibiotics