Evidence of Evolution by Natural Selection Dodo bird

FOSSILS WHAT ?- Remains of organisms ex bones, footprints HOW - Fossils show how organisms have evolved over time. - Fossils also provide evidence of organisms that are now extinct Ex Dinosaurs

Fossil Record

Fossil record Today’s organisms descended from common ancestor’s

Fossil of Archaeopteryx Lived 150 Million years ago Ancestor of modern birds Had bird and reptile characteristics Smithsonian Museum, Washington, DC

? ? ? ? Where are the Transitional Fossils? Land Mammal EX- Whale Evolution TRANSITIONAL FOSSILS

Study of Paleontology TWO WAYS OF DATING FOSSILS -Relative Dating -Absolute Dating (finding actual age) Older sediments are below younger sediments. OLDEST FOSSILS YOUNGER FOSSILS YOUNGEST FOSSILS

Geographical Distribution WHAT- the location of organisms in geographically separated locations HOW IS IT? Suggests Convergent evolution –evolving similar solutions to similar “problems” –So unrelated organisms are similar looking but because of living in similar environmenst not b/c they are closely related.

Geographical Distribution Sugar glider and Flying Squirrel - look similar, live in similar environment but not closely related. marsupial mammals vs. placental mammals

Homologous structures WHAT- Similar structures in different organisms HOW - similarities suggest common ancestor

EXAMPLES Homologous Forelimbs of human, cats, whales, & bats share same skeletal structures –similar structure but different functions –evidence of common ancestor

Homologous Structures are Evidence of a common ancestor

Vestigial organs WHAT - Structures that serve little or no function HOW – A Structure with no function suggests evolution from ancestor that had it and used it EXAMPLE - eyes on blind cave fish

EXAMPLES Vestigial organs Hind leg bones on whale Why would whales have pelvis & leg bones if they were always sea creatures?

EXAMPLES Vestigial Structures Human appendix is a vestigial structure; it no longer retains its original functionappendix

Analogous structures WHAT- Unrelated organisms having Similar structures with similar functions HOW - Show how evolution finds “Similar solutions to similar problems”

ANALOGOUS EXAMPLES SAME BODY SHAPE AND FINS BUT SHARKS ARE FISH AND DOLPHINS ARE MAMMALS

Analogous structures Both HAVE WINGS (Similar solution to similar problem) BUT NOT CLOSELY RELATED

Embryology WHAT - Similarities in how embryos develop HOW- If embryo’s develop similarly suggests a relationship between organisms (fish, frog, snake, birds, human, etc.)

DNA and AMINO ACID SEQUENCES WHAT- Comparing DNA & amino Acid Sequences between different organisms HOW – Fewer Differences= More Closely Related More Differences = Less Closely Related EX. Humans and chimps 98% similar DNA

LE Percent of Amino Acids That Are Identical to the Amino Acids in a Human Hemoglobin Polypeptide 100% 95% 87% 69% 54% 14% Rhesus monkey Species Human Mouse Chicken Frog Lamprey CONCLUSION ????????????

Which pair are most closely related? Results of a Gel Electrophoresis 1234 _________

EXAMPLES OF EVOLUTION WHAT- Examples we have actually observed HOW – Direct observation provides excellent evidence for evolution and natural selection. EXAMPLES Antibiotic Resistant Bacteria Pesticide Resistant Insects Peppered Moths

Building “family” trees Closely related species (twigs of tree) share same line of descent until their recent divergence from a common ancestor

What data from whole genome sequencing can tell us about evolution of humans

Example: the Evolutionary Hypothesis of Common Ancestry Chromosome Numbers in the great apes: 46 human (Homo)46 chimpanzee (Pan)48 gorilla (Gorilla)48 orangutan (Pogo)48 Testable prediction: If these organisms share a common ancestor, that ancestor had either 48 chromosomes (24 pairs) or 46 (23 pairs). Testable prediction: If these organisms share a common ancestor, that ancestor had either 48 chromosomes (24 pairs) or 46 (23 pairs).

Chromosome Numbers in the great apes (Hominidae): human (Homo)46 chimpanzee (Pan)48 gorilla (Gorilla)48 orangutan (Pogo)48 Testable prediction: Testable prediction: Common ancestor had 48 chromosomes (24 pairs) and humans carry a fused chromosome; or ancestor had 23 pairs, and apes carry a split chromosome. Centromere Telomere Ancestral Chromosomes Fusion Homo sapiens Inactivated centromere Telomere sequences

“Chromosome 2 is unique to the human lineage of evolution, having emerged as a result of head-to- head fusion of two acrocentric chromosomes that remained separate in other primates. The precise fusion site has been located in 2q13–2q14.1 (ref. 2; hg 16: – ), where our analysis confirmed the presence of multiple subtelomeric duplications to chromosomes 1, 5, 8, 9, 10, 12, 19, 21 and 22 (Fig. 3; Supplementary Fig. 3a, region A). During the formation of human chromosome 2, one of the two centromeres became inactivated (2q21, which corresponds to the centromere from chimp chromosome 13) and the centromeric structure quickly deterioriated (42).” Homo sapiens Inactivated centromere Telomere sequences Hillier et al (2005) “Generation and Annotation of the DNA sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731. Human Chromosome #2 shows the exact point at which this fusion took place Chr 2

Artificial selection A rtificial breeding can use differences between individuals to create vastly different “breeds” & “varieties” “descendants” of the wolf “descendants” of wild mustard

Natural selection in action Insecticide & drug resistance –insecticide didn’t kill all individuals –resistant survivors reproduce –resistance is inherited –insecticide becomes less & less effective

Evolution of Drosophila All of the 500+ endemic species of Drosophila in Hawaiian archipelago descended from common ancestor that reached Kauai over 5 million years ago

Witness to Evolution Peppered Moth –dark vs. light variants Peppered moth

Year% dark% light

Peppered moth Why did the population change? –early 1800s = pre-industrial England low pollution lichen growing on trees = light colored bark –late 1800s = industrial England factories = soot coated trees killed lichen = dark colored bark –mid 1900s = pollution controls clean air laws return of lichen = light colored bark –industrial melanism

How would an evolutionary biologist interpret these gel electro results?

Any Questions??