Charles Darwin Studies of Evolution

Darwin Galapagos Island Studies: Darwin observed many species in their natural geographical locations. He began to realize the animals had small differences that made them well suited for their environment. From this, he began to formulate ideas about evolution. Galapagos Island Studies: Tortoises: Shell shape and neck length fit the habitat and available food on the island

Darwin Galapagos Island Studies: Darwin observed many species in their natural geographical locations. He began to realize the animals had small differences that made them well suited for their environment. From this, he began to formulate ideas about evolution. Galapagos Island Studies: Finches: Beak shapes fit the need of the different foods available in their habitat (insects, fruit, nuts, seeds, leaves, etc)

Darwin’s Influences Geology: the earth is old – Charles Lyell Organisms change – Jean Baptiste Lamarck Populations are limited – Thomas Malthus Farmers/Breeders can select for best traits

Geology - Lyell (1830’s) Charles Lyell helped scientists to see that the processes that were shaping the earth (volcanoes, earthquakes, erosion) happened over millions of years. Darwin asked – if the earth could change over millions of years, could life forms change too?

Three main ideas about how organism change over time Jean Baptiste Lamarck Three main ideas about how organism change over time Tendency towards perfection Use and disuse Inheritance of acquired traits

Lamarck cont. Tendency towards perfection: Organisms constantly try to improve themselves – acquiring traits to help them survive Ex: Giraffes

Lamarck cont. Use and Disuse: Body parts that get used more, become prominent, body parts that are not used waste away Ex: Crab claw

Lamarck cont. Inheritance of Acquired Traits Based on first two ideas, organisms change their traits over the course of their lives The last idea is that they pass on these acquired traits

Is this really true? Can you pass on acquired traits?

Video Clip – How does this relate to Lamarck’s Theories?

Population Growth - Malthus Thomas Malthus was an economist who published a book about human populations in 1798. Malthus predicted that the human populations were going to out grow the resources on earth (***Remember – Limiting factors***) Darwin suspected this was the case for other living things as well

Artificial Selection Artificial Selection: Plants and animals have natural variations (differences within the population). Farmers bred their best plants and animals, because it produced more profit for them (artificially selected for the best traits)

(Extra Artificial Selection Info) Breed: a group within the same species (that means they can mate and produce fertile offspring) All dogs are the same species, Canis familiaris, and descendents of wolves Dog Breeders selected desirable traits and only allowed dogs with that trait to mate, creating different breeds Artificial selection provides a model that helps us to understand natural selection

Vocabulary Darwin thought artificial selection was occurring naturally in the world Fitness: The ability for an organism to survive and reproduce in its environment Adaptation: Inherited characteristic that increases an organisms chance of survival

Darwin’s idea – Natural Selection Variations exist in populations Some variations are favorable Not all young produced in each generation can survive The individuals that survive and reproduce have the favorable variation and pass it on

Darwin – Survival of the fittest The organism most fit to live in its environment will survive and pass on the traits *** MISCONCEPTION ALERT: Fittest is not the same as strongest

Darwin Brain Pop

Funny Simpsons Clip (Is this REALLY how evolution happens?)

 Home Work!  Concept map!

Natural Selection Quick write: Lamarck was wrong, giraffes don’t stretch their necks then pass on the longer neck trait. How would DARWIN explain the increase in giraffe height over time using the main points of natural selection?