Evolution • Change over time • Gradual • Large groups (not individuals)
Theory • Well – supported • TESTABLE explanation • Not just an “I have a theory” • Idea/Opinion not Theory!!! • Theories can change • Theories can be false
Charles Darwin • Born in England • Set Sail and traveled (H.M.S. Beagle 1831) • Recorded MANY observations • Which became evidence • To support how life changes over time. • WROTE everything down! • ANALYZED everything!
Charles Darwin • He noticed how plants and animals seem to be adapted to their environments. • AND how some environments, even though identical, had many different plants and/or animals.
Charles Darwin • Didn’t only look at LIVE plants and animals • Fossils • Preserved remains of ancient animals.
Movie • http://video.nationalgeographic.com/video/player/places/parks-and-nature-places/coasts-and-islands/ecuador_galapagos.html
Galapagos Islands • Land Tortoises (GIANT) • Marine Iguanas (land too) • Birds (Darwin’s Finches)
Belief of the Time • Was believed during Darwin’s time, that the Earth had only been formed a few thousand years before AND • ThatNOTHING had ever changed!
James Hutton and Charles Lyell • First to say that Earth is many millions years old. • 1795 – Geological Theory (Hutton) • Change on the Earth happens slowly • Rain, Heat, Cold bury or push up the Earth • 1830 – Lyell wrote Principles of Geology • Scientists must explain past events by processes that can be OBSERVED. • Because what happened then, happens now.
Principals of Geology • Darwin read this book while on the H.M.S. Beagle • Remember: Written by Charles Lyell • He saw rocks raised from the sea floor (that had muscles on them) that were now mountains • He concluded the same ideas (Lyell had) would effect/change life too (not just rocks/land).
Lamarck’s Theory of Evolution • Jean-Baptiste Lamarck – French Naturalist • 1809 Published his theory (Year Darwin was born) • States: • Organisms adapt to their environment • Use a feature – keep it • Don’t use a feature – lose it. • Everything evolves towards perfection and complexity. • Inheritance • Did not know that behavior does NOT influence inherited characteristics. Bird Wings (Ostrich/Falcon)
Lamarck’s Theory of Evolution • But… Lamarck believed that everything evolved toward perfection and that just by needing something to survive, it would appear.
Thomas Malthus • 1798 – Theory of Population Growth • If Human populations grow unchecked, we would run out of room (living space) and food. • What keeps us in check? • War (Violence), Famine (lack of food), Disease • Basically – Death!
Charles Darwin • Realized that Malthus’ Theory of Population Growth applies to plants and Animals even more strongly. • Maple Trees – 1,000’s of seeds in one summer • Oysters – 1,000,000’s of eggs each year • Yet we are not over-run by oysters or maple trees • MORE die than survive.
H.M.S. Beagle • Darwin sailed from 1831-1836 • What did he return with? • Specimens • Plants AND Animals • Notes/Observations • Books of Data 5 Years of Data!
Darwin’s Ideas • Were RADICALfor their time • So radical, he was afraid of what would happen if he went public • So he only discussed them with his friends. • His manuscripts were published AFTER he died. • AND he knew there were some things he could not explain. • He wrote that if the missing links weren’t found, to disregard much of his work • Because he made some HUGE ASSUMPTIONS.
Alfred RusselWallace • Naturalist • Who in 1858 summed up much of Darwin’s thoughts from the previous 25 years • They did not know each other! • What do you think that did for Darwin? • Gave him the incentive and the initiative to publish his own work. • SOME of it at least.
On the Origin of Species • Includes information on Natural Selection • Process of evolution • Over millions of years • And continues now • Remember: Evolution ischangeover TIME.
Natural Variation • Differences among species • WE are all different • Fruit, milk, production, size • All inherited!
Selective Breeding • Farmers and breeders pick the BEST to breed for the qualities they want. • Produce the BEST crops, the BEST animals • This is known as Artificial Selection • Not “natural” mating patterns – humans CHOOSE.
Natural Selection • In Nature – the struggle to exist • Malthus’ work on population growth fits into this. • Is there enough food, space, necessities, traits • Examples: • Speed (are you fast enough to avoid being eaten?) • Visibility (can you be seen?)
Survival of the Fittest • Fitness • Is the ability to live and reproduce • Need to ADAPT • Need to change • Adaptations are evolution!!! • Better Suited to live in their environment • Example: Marine Iguanas • If you don’t adapt/change then you die • You die, then you produce no offspring (or just a few before you die)
Keys to Evolution! • Natural Selection • Survival of the Fittest • Generations compete to Survive and Thrive (have offspring)
OVER TIME: • Natural selection CHANGES organisms – they evolve – • This is called Decent with Modification • This IMPLIES that ALL organisms are related to one another – • They have Common Descent.
Excerpt from the book (Page 382) • “ Descent with modification also implies something else: that all living organisms are related to one another. Look back in time, and you will find common ancestors shared by tigers, panthers, and cheetahs. Look farther back, and you will find ancestors that these felines share with horses, dogs, bats and primates. Father back still are the common ancestors of mammals, birds, alligators, and fishes. If we look far enough back, the logic concludes, we could find the common ancestors of all living things. This is the principle known as common descent. According to this principle, all species – living and extinct – were derived from common ancestors.”
Excerpt from the book continued (Page 382) • “Carry the concepts of descent with modification and common descent to their logical conclusion, and what do they produce? A single ‘tree of life’ that links all livings things on Earth. Darwin conceived this idea long before he published his theory of evolution.”
THIS is the controversy! • This is a HUGE jump – there are missing links and assumptions that still have not been answered. • Is there evidence of evolution all around us? • Yes! • Does that mean we came from apes? • You decide!
What does the Fossil Record show? • (Ancient remains that are preserved.) • Shows similarities in animals • Some look the same, some do not – but STRUCTURES are similar • Homologous Structures • Vestigial Organs 37 day old fetus
Homologous Structures • Different mature forms, but develop from the same embryonic tissues
Vistigial Organs • Structures that don’t develop into mature forms