Darwin’s Voyage Objectives: Predict why certain traits are more likely to offer an advantage for survival of an organism. Cite examples of Traits that provide an advantage for survival in one environment but not other environments. Relate the structure of organs to an organisms ability to survive in a specific environment.

Vocabulary Write the definitions to the words as we talk about them. 1. Scientific Theory- 2. Evolution- 3. Species- 4. Natural Selection- 5. Variation- 6. Adaptation-

HMS Beagle Sets Sail 1831 5 year world trip Charles Darwin 22 Ships naturalist noticed big difference in plants and animals developed Scientific Theory ‘Evolution by Natural Selection’

South America

Argentina Armadillo Sloth

Darwin amazed at diversity More diverse than ever thought-currently 1.7 million species. puzzled : bones of dead large animals looked like small animals of present. Why only smaller sloths alive today?

Galapagos Islands

Similarities Galapagos Is Mainland S.A. same same

Differences Galapagos Mainland S.A. Island #1 Island #2 no fly fly large claws/ small claws/ slippery rocks leaves on trees Island #1 Island #2 dome shaped shell saddle shaped

Mainland animals somehow got to island Offspring became different than relatives

Beaks of Finches suited to life it led. insects sharp beaks seeds strong, wide Adaptation- a trait that helps an organism survive and reproduce.

20 years of Thinking “Perhaps, the species gradually changed over many generations and became better adapted to the new conditions.” evolution- gradual change in a species over time. Darwin’s ideas are ‘Theory of evolution’. Scientific theory – a well tested concept that explains a wide range of observations.

Man-made selective breeding English farmers----------fine wool Darwin pigeons----------large fan tail Nature ???????

1858 The Origin of Species -evolution occurs by natural selection- process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species

Natural Selection Factors Sea Turtles 100 eggs all survive full of turtles not enough resources not enough to eat not able to escape predators new fast predator fast turtles escape Reproduce- fast swimmer trait environment has selected helpful traits unfavorable traits disappear Overproduction Competition Variations- any difference in traits between individuals of same species

Other adaptations Teeth: Animals Pgs. 312-313 Teeth: broad, flat surface, grinding (grasshoppers, termites, snails, cows, horses, pandas) sharp, pointed, stabbing, cutting (wolves, frogs) some sharp in front, flat in back (grizzly bears, humans) Birds pgs. 417-418 Plants pgs. 250-251 Herbivore Carnivore omnivore

Escape Variations Hard shells spiny skin play dead stingers claws bitter taste smelly sprays

No variation = Everything stays the same Mutations in genes or allele shuffling bring variation only genes from inherited traits can be acted upon by natural selection Darwin didn’t understand all this, but knew somehow it was connected

Evolution in Action finch beak size changes due to natural selection 1977 Daphne Major Galapagos Is. 25 ml. rain Plants died Following year finches had large stronger beaks Fewer small seeds available Small beak finches didn’t survive drought Evolution by natural selection in 1 year Ate large seeds in tough thorny pods Finches w/ large strong beaks could open pods -not smaller weak, beak finches

Evolution of Peppered Moth 1700’s English Peppered Moth light gray Natural selection favored black moths Birds could only see black peppered moth against light gray trees 1850 most peppered moths were black Industrial Rev. smoke blackened trees Gray moth easy to see now Birds ate gray moths

How do new species form? Geographic isolation-members of species get cut off from rest of species and can no longer mate with them and evolve with different traits than the original group. Ex: river, volcano, Mt. Range, ocean wave.

10,000 y.a. they were the same species ! Aberts Kaibab Isolation in forest N. of Grand Canyon Az. Might have evolved to a new species.

Geographic Isolation on a Worldwide scale -Organisms able to migrate to all places before continents separate -Species become isolated -Species in each area evolve independently

Australia -isolation brought marsupials

Natural Selection

Vocabulary Matching 1. Scientific theory a. Similar organisms that can mate with each other and produce fertile offspring. 2. Evolution b. A trait that helps an organism survive and reproduce. 3. Species c. Gradual change in a species over time. 4. Natural selection d. A well-tested concept that explains a wide range of observations. 5. Variation e. Individuals better adapted to their environment, able to survive and reproduce than other species. 6. Adaptation f. A difference between individuals of the same species.