Evidence of Evolution and Natural Selection

Evolution The development of new types of organisms from preexisting types of organisms

Evidence of Evolution Short scale of human life makes it hard to understand evolution –Humans have only been on earth for approximately 200,000 years. –The earth is 4.6 Billion years old

A Geologic Calendar is a calendar that places the entire life of the Earth and places it on a one year calendar. The formation of Earth would be at 12 midnight, January 1st of the Geologic Calendar and the current day would be midnight December 31st. To place an event on the calendar, you divide the date it happened by the age of the Earth, 4.5 billion years, then multiply that by 365 to find the date and time to include the event. January 1st, the Earth was formed, and February 20, the Earth's crust formed. Life began on March 1st, and our earliest fossils/bacteria appear on March 26. Land plants didn't appear until November 4, and fish appeared November 20. December 11th there was a mass extinction and December 27 dinosaurs became extinct. Humans appeared December 31st at around 11:56 p.m. and all recorded human history happened in the last 4 seconds of December 31st.

Charles Darwin (English Scientist) First published modern evolutionary theory (On the Origin of Species by Means of Natural Selection) –1831 took a trip around the world –Stopping everywhere he took different forms of life –Returned to England with many questions

Darwin’s Voyage

Adaptations are evidence of evolution –Look at the picture below. What are some adaptations of this bass?

Camouflage Some species just blend into their environment

Bald Eagle

Brown Bear

Structural Features Homologous structures –Structural features with a common evolutionary origin

Homologous Structures Salamander, Lizard, Turtle, and Opossum

Analogous Structures –Similar in function but do not have a common evolutionary origin Look on page 401 –Figure

Vestigial structures –No present day function but was probably useful to an ancestor on CD

Examples of Vestigial Structures Eyes on blind mole rats Tiny snake pelvic and limb bones Humans have a set of muscles for wiggling ears Appendix in a human

The appendix is about 10 cm in length, but can range from 2 to 20 cm. The diameter of the appendix is usually less than 7–8 mm.

Embryo’s –Earliest stage of growth and development in both plants and animals Very similar embryo’s in Fish, Reptiles, Birds, and Mammals (60271 on CD)

Vertebrate Embryos

Vertebrate Brains

cerebrum - controls and integrates motor, sensory, and higher mental functions, such as thought, reason, emotion, and memory. Cerebellum - serving to coordinate voluntary movements, posture, and balance in humans, being in back of and below the cerebrum and consisting of two lateral lobes and a central lobe. Brain Stem - sustaining the basic functions of life, such as breathing and blood pressure.

Biochemistry CAT TAC –DNA is made of the same building blocks just in a different order –DNA in a human could be AATGGGCCC TTACCCGGG –DNA in a tree could be AAGTTTAGC TTCAAATCG

Offspring that survived had certain traits that were helpful These organisms then passed down traits to their offspring Which leads us to Natural Selection

Natural Selection Mechanism for change in populations ; occurs when organisms with certain variations survive, reproduce, and pass their variations to the next generation – peredmoth.html

Natural Selection

Evidence of Evolution Adaptations Homologous Structures Analogous Structures Vestigial Structures DNA Embryo’s Camouflage

hominid Any of various primates of the family Hominidae, whose only living members are modern humans. Hominids are characterized by an upright gait, increased brain size and intelligence compared with other primates, a flattened face, and reduction in the size of the teeth and jaw. Besides the modern species Homo sapiens, hominids also include extinct species of Homo (such as H. erectus ) and the extinct genus Australopithecus. In some classifications, the family Hominidae also includes the anthropoid apes. any of various omnivorous mammals of the order Primates, comprising the three suborders Anthropoidea (humans, great apes, gibbons, Old world monkeys, and New World monkeys), Prosimii (lemurs, loris, and their allies), and Tarsioidea (tarsiers), especially distinguished by the use of hands, varied locomotion, and by complex flexible behavior involving a high level of social interaction and cultural adaptability.world primate