AP Biology Lecture 4 Big Idea 1 Evolution

AP Biology – Lecture #4 Big Idea #1 – Evolution Change in the genetic makeup of a population over time IS evolution. Adapted from Rebecca Rehder Wingerden ©

Biological evolution is supported by scientific evidence from many disciplines, including mathematics. • Scientific evidence of biological evolution uses information from geographical, geological, physical, chemical and mathematical applications. • Molecular, morphological and genetic information of existing and extinct organisms add to our understanding of evolution. Hierarchical classification: At each level of the Linnaean classification system, species are placed into groups belonging to more comprehensive groups.

Biological evolution is supported by Fossils. 1. Fossils can be dated by a variety of methods that provide evidence for evolution. ▫ These include the age of the rocks (1) where a fossil is found, �Law of superposition, “relative” age of fossils

Biological evolution is supported by Fossils. • The (2) rate of decay of isotopes (radiometric dating) including: ▫ Carbon-14 with a half life of 5730 years ▫ Uranium-238 with a half life of 4. 56 billion • “Absolute” ages of fossils can be determined by radiometric dating. • Geologist can apply an indirect method to infer the absolute age of fossils. Bozeman Biology: Radiocarbon Dating (10: 00 min. )

Biological evolution is supported by Fossils. • And the mathematical calculations that take into account information from (3) chemical properties and/or geographical data. Number of Mutations ▫ molecular clock - method compares the amount of genetic difference between living organisms and computes an age based on well-tested rates of genetic mutation over time Divergence Time (millions of years) Biochronology - age estimate based on the fauna arrangement (younger to older), used when sites that cannot be readily dated, the animal species found there can be compared to well-dated species from other sites.

Biological evolution is supported by morphological homologies. 2. Morphological homologies represent features shared by common ancestry.

Biological evolution is supported by morphological homologies. • Vestigial structures are remnants of functional structures, which can be compared to fossils and provide evidence for evolution. ▫ Skeletons of cetaceans and some snakes retain vestiges of the pelvis and leg bones of walking ancestors

Biological evolution is supported by genetics. 3. Biochemical and genetic similarities, in particular DNA nucleotide and protein sequences, provide evidence for evolution and ancestry. ▫ The same genetic code: DNA, RNA, Protein Synthesis (molecular systematics) Aligning segments of DNA: Systematists use computer software to find align similar sequences of DNA segments from two species.

Biological evolution is supported by mathematics. 4. Mathematical models and simulations can be used to illustrate and support evolutionary concepts. ▫ Construction of phylogenetic trees based on sequence data Bozeman Science Recap – Models (@10: 50) http: //www. bozemanscience. com/ 004 -evidence-for-evolution Bozeman Science Recap: http: //www. bozemanscience. com/ evidence-for-evolution-ii

Phylogenetic Trees show evolutionary relatedness

Constructing a Phylogenetic Tree • shared ancestral character - backbone (originated in an ancestor) • shared derived characteristic – hair in mammals (evolutionarily unique to a particular group, or clade)

Constructing a Phylogenetic Tree How To Build A Cladogram http: //ccl. northwestern. edu/simevolution/obo nu/cladograms/Open-This-File. swf Or http: //goo. gl/e. INl 3 y