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Principles of Evolution. Chapters: 12, 13, 14. How did life begin?. The Bubble Model (1986) by Lerman. Chemical reactions of the primordial soup took place inside bubbles of fat molecules. See page 255 in book. Primordial Soup (A.I. Oparin). Early Earth atmosphere (N, Methane, ammonia)
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Principles of Evolution Chapters: 12, 13, 14
The Bubble Model (1986) by Lerman • Chemical reactions of the primordial soup took place inside bubbles of fat molecules. • See page 255 in book
Primordial Soup (A.I. Oparin) • Early Earth atmosphere (N, Methane, ammonia) • Energy from sun, volcanoes, lightning • Chemical reactions created amino acids • Rain washed these into the ocean • Created the primordial soup.
A Brief History of Life • animation
Early Organisms • Prokaryotes are oldest organisms (3.5 billion years old) • Cyanobacteria – photosynthetic bacteria • Impact on atmosphere: Oxygen!!!!
Groups of bacteria • Eubacteria- “true bacteria”, ex. Ecoli • Archaebacteria – ancient bacteria,
Then came the eukaryotes • Appeared 1.5 billion years ago
Life moved onto land!!! Ozone layer formed
The Theory of Evolution Chapter 13
13-1 Where did the theory of natural selection come from? • Pre Darwin: • (1809) Jean Baptiste de Lamark • Variation hypothesis – evolution occurs through acquired characteristics (body changes over time) • Example: giraffe neck length
Evolution by Natural Selection • Charles Darwin (1859) • Journey of the H.M.S. Beagle – recorded all the plants and animals on journey
Darwin’s Observations • Observed gradual change – found fossils that were similar, but not identical, to the current day animal • On Galapagos island he observed finches that resembled those in South America
I. Natural Selection- survival of the fittest (Darwin) 1. Variations exist within populations
Theory of Natural Selection 2. Some variations (mutations) are more advantageous for survival and reproduction than others
Theory of Natural Selection 3. “fit”organisms survive and reproduce – genes are passed to offspring
Isolation- leads to a new species, two population of same species can not breed • Extinction- leads to species replacement
Adaptations • Changing of a species that results in its being better suited to its environment (choosen by natural selection) • Mutations
Structural Adaptations Mimicry Camouflage Warning coloration
Structural Adaptation: 1. Mimicry Example: Viseroy and Monarch Butterflies
Viceroy Monarch
2. Camouflage • adaptations that allows an organism to "blend" into it's environment • Examples:
More examples of Camo.: Sea Dragon
Structural Adaptation: Warning: Standing out Poison Arrow Frog
A regal ring-necked snake displaying its aposematic coloration
Physiological Adaptation Changes in metabolic processes: venom, warm vs. cold blooded
Fossil Evidence • Missing links between groups of organisms. • Compare fossils with current day species
Structures and Evolution • Homologous structures – agreeing • Similar structures and derived from the same body part. • Ex. Bone structure
Vestigial structures • Remnant of another structure • No function, reduced in size • Ex. Appendix, tailbones,wisdom teeth in humans, hipbones in whales,
Tonsils Coccyx (tail bone) Appendix Little toe Wisdom teeth Nipples on males Nodes on ears "Darwin's points" Ear muscles for wiggling Body hair Some Alleged Vestigial Organs in Man
Analogous Structures :opposite • Similar in function, but different structures • Wing of butterfly vs wing of a bat
III. Embryo Development • Theory: aquatic, gill breathing vertebrates came before land, air breathers