EVIDENCE OF EVOLUTION Chapter 15-2

Evolution defined… Evolution is a process of gradual modifications Darwin called this descent with modification

Ancestor Organism 1 Organism 2 Many animals and plants shared common ancestors and deviated from that common ancestor overtime Organism 1 Ancestor Organism 2

Fossils Fossils provide geologic evidence of evolution Fossils in older layers are more primitive than those in the upper layers

Transitional Species: Descent with modification states that newer species are modified versions of older species - Fossil record contains the intermediates

Anatomy Ex: Whale hind leg bones Vestigial Structures- remnants of organs or structures that had a function in an early ancestor. Ex: Whale hind leg bones

Anatomy cont. Homologous Structures: body parts that are similar in structure may have different functions Indicating at some point way in the past they did the same job and came from a common ancestor

Anatomy cont. Analogous Structures: same functions but different development ex. a butterfly wing and a bat wing Indicates that populations evolved to be better suited to the environment

Biogeography Geographical distribution of living creatures. Similar species are found in similar places showing common ancestry. Ex: marsupials in Australia

Embryology Some stages of embryo development of different organisms are similar Explanation: Share a common ancestor

Biological Molecules DNA  RNA Proteins Similar proteins means similar DNA The longer it’s been since they shared a common ancestor the more differences in protein

Whale Fish Venn Diagram Make a double bubble using the following terms: Live birth Swim Live in water Some hair Most lay eggs Scaly skin Warm blooded Breathe with lungs Breathe with gills Move tail up and down Cold blooded Move tail left and right

Whale Video http://www.teachertube.com/viewVideo.php?title=Whale_evolution&video_id=65653

Whale Fossil Chart Review Questions (answer in COMPETE sentences) What do you think is the main difference between the Mesonychid and Ambulocetus? What is the main difference between Rodhocetus and Basilosaurus? Where do you think Rodhocetus spent most of his time? Why?

EVOLUTION IN ACTION Chapter 15-3 pp. 308-311

Evolution defined… Evolution of a population is due to environment and the interaction of other species Evolution acts on phenotype, not genotype

Artificial Selection Humans breed for specific traits causing differences in species (i.e. dog breeding)

Examples of Evolution Convergent evolution: Organisms with very different ancestors become more alike due to a common environment Ex. fish and whales- compare analogous structures

Divergent evolution: populations become more and more dissimilar to adapt to the environment-compare homologous structures Appearance of birds with different sized beaks that are specific for size of bird seed

Adaptive radiation Population undergoes divergent evolution until it fills all areas of the environment

Co-evolution: as one species evolves another does (parasites and hosts)