UNIT 9 Evolution

Darwin and Evolution

Charles Darwin  Naturalist   Traveled on HMS Beagle for 5 years (22 yrs old)  Galapagos islands- unique animals like the turtles and finches found there  Travel and observations lead to Darwin's ideas………

Influences on Darwin Hutton: Earth is shaped by geologic forces-older than millions of years Lyell-processes on Earth have been happening for a long time and these processes have shaped the Earth’s geologic features Lamark-use and disuse,inheritance of aquirred traits Malthus-human population will grow faster than raw materials can be produced

Natural Selection  Explanation of how populations change over time ( a very long time)  Another way to say this: Survival of the Fittest- those organisms within the group have some sort of variation that allows them to survive and produce offspring with the same variation Survival of the Fittest- those organisms within the group have some sort of variation that allows them to survive and produce offspring with the same variation

For all populations these factors must exist for natural selection:  Organisms overproduce- more babies born than will actually survive  Variations exist within the species- example: fish scale color  Variations passed on to offspring  Overtime the population changes to exhibit the favorable variations

Artificial selection Humans select desired traits Dog breeds

Descent with modification-each living species has desended with changes from other species over time. Common descent-all species derived from common ancestor

Evidence of Evolution Seen in:  Structural changes a. camouflage- blend into surroundings b. mimicry- look like another organism with a favorable trait b. mimicry- look like another organism with a favorable trait  Physiological changes- metabolism ex. Drug resistant bacteria ex. Drug resistant bacteria

Camouflage Mimicry

We can see the changes by showing relationships between organisms 1.Fossils- a. molds (left behind by soft tissue) a. molds (left behind by soft tissue) b. bones b. bones

2. Anatomy-look at structures a. homologous- similar in arrangement and/or function a. homologous- similar in arrangement and/or function

b. Analogous – similar in function but not in structure b. Analogous – similar in function but not in structure

 C. Vestigial- organ or structure not used any more like our appendix. Do you know what animal has a working appendix? RABBITS RABBITS  Other examples: Molars in vampire bats leg bones in snakes and whales ear muscles in humans

 3. Embryology- study of embryos. Look for similarities.

 4. Biochemistry-horseshoe crab biochemistry more similar to spiders than other crabs.  5. Geographic distribution-similar animals develop in different areas due to common conditions.

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Population Genetics  Gene pool- # or % of alleles in a population  Allelic Frequency- % of a specific allele in a gene pool. (Ex.- how many B’s or b’s in the classroom)  Do populations change? YES!!!!  Genetic Equilibrium- no real change in allelic frequency of population

Ways a Population Can Change  Mutation- (in gametes)  Sexual reproduction  Genetic Drift- alteration by chance event like an earthquake, fire, flood-change in allelic frequency  Gene Flow- movement in or out of organisms in a population. Ex. All the people with blue eyes moved to Canada- what would happen to the allelic frequency of b?  Traits controlled by a single gene will have a greater chance of differences in allelic frequency and therefore lead to change.

3 Types of natural Selection Which group is favored?  Middle group- STABALIZING SELECTION  One extremes- DIRECTIONAL SELECTION  Both extremes- DISRUPTIVE SELECTION

Hardy –Weinberg Principle In order to maintain genetic equilibrium: 1. Random mating 2. Large population 3. No movement in or out 4. No mutations 5. No natural selection

How do new species form?  Speciation- evolution of a new species-new group is unable to breed with old group  Behavioral isolation- wrong mating dance  Geographic Barrier- splits group and over time changes occur in one or both groups that do not allow them to breed with each other.  Reproductive isolation- 2 groups can’t mate with each other –parts don’t fit, different mating cycles (Temporal)

How fast does evolution occur?  Speciation Rate- speed of evolution  Gradualism- speciation occurs gradually over a long period of time  Punctuated- short quick bursts( dinosaurs)

The Classification of Organisms

Branch of biology that groups and names organisms based on similarities

Aristotle started grouping plants into 3 categories: herbs, shrubs, and trees

Based his groupings according to physical and structural characteristics Had a 2 word naming system like a first and last name called BINOMIAL NOMENCLATURE Used Latin because it is universal and it’s a dead language (it doesn’t change)

When we name organisms we usually just give the Genus and species name like Homo sapien Note that the Genus name is capitalized and the species name is in lower case In print you will see the Genus and species name in italics.

 Biggest to smallest (Domain) Kingdom Phylum Class Order Family Genus Species Kings play chess on fine green sand

Structural similarities Breeding behavior Geographical distribution Chromosome comparison (how many bases match) Biochemistry

Domains  Bacteria-prokaryotic, cell wall made of peptidoglycan,common like strep,staph Kingdom-Eubacteria  Archaea-prokaryotic,live in extreme environment Kingdom- Archaebacteria  Eukarya- eukaryotic cells Kingdoms-Protista,Fungi,Plantae,Animalia

Domain Eukarya  Protista-animal like, plant like, fungi like, most single celled, some photosynthetic  Fungi- heterotrophs, decomposer  Plantae- multicellular, photosynthetic, cell wall  Animalia- multicellular, heterotroph