Ch. 15 Evolution – Change Over Time QUESTIONS OF THE DAY What is natural selection? How do you know what a dinosaur eats? What would you be looking at? Do you think a species gets better at doing something over a period of time? Why or why not? Do you look like any of your grandparents? Why or why not? What do you think would happen if a good trait were to show up in a population? What would need to happen for it to stay in the population?

Ch. 15 Evolution – Change Over Time History of Evolution Charles Darwin proposed the theory of evolution by natural selection. Natural selection is the driving force behind evolution. Cause and effect relationship Galapagos Islands off the coast of Peru in South America Darwin worked with finches.

Ch. 15 Evolution – Change Over Time

Ch. 15 Evolution – Change Over Time

Ch. 15 Evolution – Change Over Time Natural Selection Term: survival of the fittest. (Reproduction) FIT: Better suited to live in the environment. (positive adaptations) Reproduction is essential to pass the positive traits on to offspring. Organisms with the most favorable traits are better suited to survive and pass on genes. Least favorable traits will die with the organism. Therefore, the organism will not pass on the genes

Ch. 15 Evolution – Change Over Time Over time, good traits accumulate in a population. Good traits stay, bad traits go away. (typically)

Ch. 15 Evolution – Change Over Time In the event of a Zombie Apocalypse, the humans with the best traits that are most suited for the environment will survive and pass their genes on to their children. I don’t have to outrun the zombies. I just have to outrun you in order to pass on my strategy genes to my children.

Ch. 15 Evolution – Change Over Time Selective breeding = breeding plants and animals for specific traits Sexual selection = mate picks desired traits.

Ch. 15 Evolution – Change Over Time Descent with Modification All organisms are derived from existing organisms with slight changes. Modification by Natural Selection As the environment changes, fitness changes and new adaptations will arise.

Ch. 15 Evolution – Change Over Time

Ch. 15 Evolution – Change Over Time

Ch. 15 Evolution – Change Over Time

Ch. 15 Evolution – Change Over Time Evolution: The Evidence FIVE pieces of evidence for evolution. Fossil Record Comparative Anatomy Analogous Structures Vestigial Structures Embryological Development

Ch. 15 Evolution – Change Over Time Fossil Record Compare extinct (dead) with extant (still surviving) organisms Shows descent with modification

Ch. 15 Evolution – Change Over Time Comparative anatomy Homologous structures = structures that are similar due to a common ancestor. Ex. Arm bones of vertebrates (humerous, radius, ulna) By comparing the traits of organisms, a common ancestor can be established

Ch. 15 Evolution – Change Over Time Overtime, organisms adapt to their changing environment. Horses were once the size of dogs. Overtime, the horse grew larger and stronger.

Ch. 15 Evolution – Change Over Time Analogous structures Similar features due to a common environment NOT a common ancestor. Similar niche Ex. Fish and Dolphin tails

Ch. 15 Evolution – Change Over Time Vestigial structures Remnants of evolutionary past. Old structures that no longer serve a purpose. Ex. Appendix, tailbone, wisdom teeth, tonsils.

Ch. 15 Evolution – Change Over Time Comparative biochemistry DNA RNA Amino acid based protein ATP energy Phospholipid bilayer Universal genetic code

Ch. 15 Evolution – Change Over Time Comparative biochemistry 98% of human DNA is the same as a chimpanzee’s genetic code

Ch. 15 Evolution – Change Over Time Embryological development Similar step by step development of the embryo.

Ch. 15 Evolution – Change Over Time Geographic Distribution Organisms evolve to fill niches in environment (Dingo and Coyote) Dingos live in the outback of Australia Coyotes live in a similar environment in the US Both can breed with one another.

Ch. 15 Evolution – Change Over Time Convergent Evolution Different organisms developing similar traits to fill a similar niche. Killer whale and a Great White Shark Analogous structures

Ch. 15 Evolution – Change Over Time Divergent Evolution Organisms adapt to live in different environments and develop different traits. (different niche) Blue whale and killer whale or Great White Shark and whale shark. Homologous structures

Ch. 15 Evolution – Change Over Time Co-evolution Organisms changing in a close relationship. Parasite/host predator/prey flower/pollinator