Theory of Evolution Slow Change over time

I. Fossil Record A. The fossil record of Earth shows evidence that species of living things have undergone perpetual changes, caused by changes in gene frequency. B. Changes in gene frequencies ☞ new species

C. E.g. Evolution of the modern horse From Eohippus (5 toes, > 1 foot, size of a cat) To Equus (1 toe, 5 feet or more at the withers)

E.g. Evolution of the modern horse

D. Charles Darwin 1. Circa 1840, Charles Darwin sailed around the world for 5 years on the HMS Beagle.

2. 2. Voyages of the HMS Beagle

3. He observed great biodiversity. a. E.g. Birds Frigate bird Galapagos dove Blue-footed booby Albatross Penguin

b. Finches

c. Reptiles Galapagos tortoise Marine iguana

d. Plants Passion flower Capparidaceae Button mangrove Beach morning glory Passion flower Achupalla plant. AristolochiaLava cactus

4. Darwin’s observations lead to … a. Ideas to try explain what he had seen. b. Publishing of “The Origin of the Species”

5. Ideas contributing to the theory of evolution a.Evolution = slow change over time, sometimes causing new species to emerge b. Species = a group of organisms that :  look very much alike  share a common ancestry  are capable of breeding and producing viable offspring that are capable of reproducing

b. Species  E.g. all dogs, same species  However, horse + donkey = mule

c. Natural selection i. Species’ members survive if they have the genes that are best suited for the current environmental conditions. ii. Species unable to adapt to the current conditions become extinct.

c. Natural selection iii. Nature selects “for” advantageous traits (genes) and ”against” traits that do not improve a species’ chances of survival. iv. Individuals with advantageous traits survive to breed and pass those traits to the next generation.

c. Natural selection v. Gene frequency changes are caused by natural selection. vi. Natural selection may lead to evolutionary change.

vii. The Peppered Moth (an example of natural selection) Light Form of peppered moth

vii. The Peppered Moth Facts:  Pre-Industrial revolution (late 18th & early 19th Centuries), ratio of light peppered moths to melanic (dark) was 50:50 Light and melanic (dark) forms

vii. The Peppered Moth  Industrial Revolution, coal burning by factories caused tree trunks to become dark- colored.  Bird predators ate more light moths, more melanic moths survived.  # light moths < # Melanic moths

g. The Peppered Moth  By the 1950’s, coal burning stopped.  Ratio of light to melanic returned to 50:50.  Moths did NOT change color.  Both colors always existed in the gene pool.  Gene frequencies changed.

4. Adaptation = an anatomical structure, physiological process, or behavioral trait that improves an animal’s fitness for survival = an anatomical structure, physiological process, or behavioral trait that improves an animal’s fitness for survival

5. Common descent = all life forms come from some original life form; closely related species have a common ancestor

6. Homology a. = similarity of organisms due to common embryonic or evolutionary origin b. E.g. a vertebrate forelimb could be an arm, a wing, or a flipper  made of same bones  may have different f(x)s

c. Homologous structures

whale horse mole bat human bird humerus radius & ulna metacarpals carpals

7. Adaptive Radiation = production of ecologically diverse species from a common ancestral stock (see text figure 1.17)

8.Extinctions  AT LEAST five major extinctions in geological time  ¿ 65 million years ago during the Cretaceous era, what animal group become extinct?  ¿Why?

8. Extinctions  Dinosaurs. Unable to adapt to the changing environmental conditions (did not have the gene combinations to permit their survival

E. Rapid evolution? 1. Antibiotic use creating “super germs” 2. Use of pesticides creating “super bugs”