Unit 12 – Intro to Evolution

1. Unit 12 – Intro to Evolution Summary color is pink; vocabulary is underlined. Hyperlinks are in green; they will take to you videos and animations. Background Image:http://magickcanoe.com/insects/angry-katydid-3-large.jpg

2. This katydid is well adapted to look like the leaves of its habitat. In this unit we will discuss theories of evolutionand adaptation that lead to such phenomenon within populations. Background Image:http://magickcanoe.com/insects/angry-katydid-3-large.jpg

3. Due to the sensitive nature of this unit I ask that we keep in mind that the theories behind evolution can often breed tensions because of religious teachings. These theories are part of understanding the world of science. Our scientific discussions will focus on attempting to explain natural phenomena (or events). Differing religious opinions are okay, but religious based theories on the history of life are not the focus of this class. Sensitivities

4. Theory in everyday life is different from the scientific theory– i.e. someone has a theory on who will win the Super Bowl. • A scientific theory is an explanation of natural and physical phenomena that is supported by a large body of scientific evidence from multiple, independent researchers. • Unlike hypotheses, theories are well- established and highly reliable – they are subject to change as new information is obtained or technologies developed. Scientific Theory Textbook Reference pg. 18

5. The Earth has millions of kinds of organisms with an amazing amount of diversity, yet, we all share similarities, the core of which is DNA. (Every living organism has it!) • How are all these different organisms related to each other? • Evolution, or change in a species over time, is the process by which modern organisms have descended from ancient ones. • For example, the ancient horse a was about the size of a medium dog! EvolutionTextbook Reference pg. 10 http://www.eurekalert.org/images/release_graphics/yu0926.jpg

6. The British scientistCharles Darwin is credited the most in our understanding of evolution. After college in 1831, Darwin joined the crew of the ship the H.M.S. Beagle for a voyage around the world (5 years!). • During his travels, Darwin took observations, specimens, and collected evidence for the variety of species on this planet. • He later proposed a hypothesis about the way life changes over time . • That hypothesis, now supported by a larger body of modern evidence, became the theory of evolution. Who is CharlesDarwin? Textbook Reference pg. 393-396 http://www.anselm.edu/homepage/jpitocch/genbios/22-05-VoyageOfHMSBeagle-L.gif

7. When the ship was anchored, he collected plant and animal specimens. • In one single day in the Brazilian rainforest he collected 68 different species of beetles! • When sailing, Darwin took observations of the organisms and kept detailed notes. Darwin Cont. http://upload.wikimedia.org/wikipedia/commons/thumb/7/7f/Striped.love.beetle.arp.jpg/250px-Striped.love.beetle.arp.jpg

8. Probably his most influential location on Darwin’s journey was the Galápagos Islands off the coast of South America; 500 miles west of Ecuador in the Pacific Ocean, directly on the equator. • Although they were very close together (50 to 60 miles and still within eye sight), the islands had very different climates and very different plants and animals living there. Galápagos Islands Textbook Reference pg. 394 http://www.cnn.com/EARTH/9707/17/Galápagos /Galápagos .lg.jpg

9. Darwin learned that each island had a different variety of land tortoises. • One island turtle has a long neck and curved opening in the shell to allow for the organism to search for food because of sparse vegetation (or plant life). • Yet, another island with a lot of plant life has a turtle that is very close to the ground the with a short neck making it easier to eat. http://upload.wikimedia.org/wikipedia/commons/a/a1/Gal%C3%A1pagos_tortoise_Santa_Cruz.jpg

10. In his travels, Darwin compared living organisms to fossil evidence that he collected throughout his voyage. • Afossilis the preserved remains of an ancient organism. • Some living organisms he observed looked like preserved fossils, while others were unlike any creature he had ever seen! (EX Dinosaurs) • His evidence posed more questions. • Why had so many species disappeared? • How are ancient organisms related to modern organisms? Darwin Cont. Textbook Reference pg. 399-400 http://english.people.com.cn/200406/07/images/0606_112.jpg

11. Darwin used his notes and scientific findings to build his theory of evolution; it took him years before he was willing to publish his work because of the drastic controversy it would (and did) cause. • His book, On the Origin of Species [By Means of Natural Selection]was published in 1859. • In it he argued that life has been evolving for millions of years. • His book sold out in the first day and became an instant best seller! On the Origin of Species Textbook Reference pg. 396 http://rationalrevolution.net/images/darwin_ape.jpg The political cartoon (1861) is just one example of the negative reaction to the theories explained within the book.

12. Use the chart to list the 5 themes from On the Origin of Species. Five Basic Concepts of Natural Selection

13. All species have genetic variation(we now know) caused by differences in the DNA and genes of an organism (EX color of fur; shape of teeth; blood type; hormone levels). • Darwin argued that variation was normal and was important. • Characteristics vary within a species and this can affect the survival of individuals. 1. Variation Among Species Textbook Reference pg. 407,409 http://www.swarthmore.edu/NatSci/cpurrin1/evolk12/gps/images/saddlestretch.jpg

14. Organisms produce more offspring than can survive. • Some that survive do not produce offspring. • Organisms are forced to compete for resources. • This is called the struggle for existence; members of each species must compete for the necessities of life (food, water, & space). 2. Struggle for Existence Textbook Reference [Competition] pg. 38-39

15. Survival affected by short-term natural disasters • EX droughts, fires, floods, snowstorms, hurricanes, etc. • And affected bylong-term changes in the environment • EX ice ages, biome shifts, etc http://eoimages.gsfc.nasa.gov/images/imagerecords/79000/79553/sandy_goe_2012302_1745_lrg.jpg

16. Darwin began to realize that organisms have certain characteristics or behaviors that allow them to survive in their environment. • Anadaptation is an inherited characteristic (EX a longer neck) that can increase an organism’s chance of survival. • If they live long enough, they will reproduce and pass on their genes. 3. Adaptations Textbook Reference pg. 9, 397-399 http://www.cedar-foundation.org/uploads/images/300%20Turtle.jpg

17. Knowledge Check The diagram below shows features of the varieties of finches in the Galapagos. How can the diagram help us understand the evolutionary terms like variation and adaptation? Turn and talk to your neighbor. http://www.pbs.org/wgbh/evolution/library/01/6/images/l_016_02_l.gif Textbook Reference pg. 469

18. Some organisms are more suited to their environment due to natural variations in the species. • Darwin used the termfitnessto define an individual’s ability to survive and reproduce. • Individuals that are fit to their environment survive and leave more offspring than those who aren’t. 4. Fitness http://farm1.staticflickr.com/49/125046333_7123c38e73_z.jpg?zz=1

19. Living species today are descended (with modifications) from common ancestral species that lived in the past. • Over time, traits [i.e. genes] for lessfavored characteristics will be eliminated from the gene pool. • Species today, therefore, look different from their ancestors because of historical changes. 5. Descent with ModificationTextbook Reference [Diagram] pg. 374-375 http://lh4.ggpht.com/-UGl8KKcTbyM/Twv3HAUUfXI/AAAAAAAAKPI/uVxQI5FXWYo/image_thumb3.png?imgmax=800 Sketch, Darwin’s Notebook Branching “Tree of Life”

20. The diagram below shows descent with modifications for modern elephants. How can the diagram help us understand evolutionary terminology like variation and descent with modification? Turn and talk to your neighbor. Knowledge Check http://www.zo.utexas.edu/faculty/sjasper/images/22.7.gif

21. Natural selection is the process by which individuals that are better suited to their environment survive and reproduce most successfully (AKA survival of the fittest). • Organisms that are well adapted will be able to survive. Over time, natural selection leads to changes in the characteristics of a population. • New species develop, increasing biodiversity. • Video • Video 2 What is the gist of the book?

22. Darwin understood variationcan bea positive thing! • He used the example thata dairy farmer would benefit from breeding a cow that produces a lot of milkversus a cow that does not. • He coined the term artificial selection where nature provided the variation and humans selected those variations that are useful (EX a pure breed dog, the best looking horse). Animation Artificial SelectionTextbook Reference pg. 469 http://www.farmland-thegame.eu/images/animals/Dairy-cows-pict-1.jpg

23. Many scientific theories and observations in the years before Darwin helped to influence his theories on evolution. • Some scientists long before Darwin came to similar conclusions. • Most people at the time thought Darwin’s opinions too radical (or out there) to accept. Darwin’s Influences http://www.victorianweb.org/science/darwin/darwin_beard.gif

24. The French scientist Jean-Baptiste Lamarck was one of the first to recognize that life changes over time. • He argued that certain traits present in an organism are always passed on to offspring. • EX giraffes stretched their necks to reach food. • Their offspring and later generations inherited the resulting long necks. • Although some of his theories were flawed, the idea that species change and adapt greatly influenced the theory of evolution. Lamarck http://en.wikipedia.org/wiki/File:Jean-baptiste_lamarck2.jpg

25. In 1795, the geologist James Hutton published his hypothesis on the Earth’s geology formed very slowly over time, millions of years and are shaped by natural forces (mainly the weather). • Most Europeans at the time believed that the Earth was only a few thousand years old, but Hutton proposed that the Earth had to be much older. • If the Earth were millions of years old, it would help to explain the SLOW process of evolutionary change. Hutton http://upload.wikimedia.org/wikipedia/commons/thumb/0/0e/Hutton_James_portrait_Raeburn.jpg/220px-Hutton_James_portrait_Raeburn.jpg

26. Lyell’s book was published just before Darwin set sail in the Beagle. • In his book, Lyell proposed that scientists can observe the processes that shaped the Earth millions of year ago in the present (volcanoes, earthquakes, etc. all change how the world looks). • Darwin wondered if the Earth can change over time, can species change too? Lyell http://www.anselm.edu/homepage/jpitocch/genbios/22-x3-Lyell.jpg

27. A contemporary (same time frame) of Darwin, Alfred Wallace wrote an essay on evolution and the process of natural selection using his studies of plants and animals a year before Darwin published Origins. • Darwin and Wallace both presented their findings at the same scientific conference. • Darwin is remembered while Wallace is often forgotten. Wallace Textbook Reference pg. 396,468 http://io.uwinnipeg.ca/~simmons/16cm05/1116/22-x5-AlfredWallace.jpg

28. Extinction: the destruction of a population. • If an entire population of a species cannot adapt, that species becomes extinct. • 99% of all species that have ever lived are now extinct! • Humans contribute to the extinction of many plants and animals because of pollution, loss of habitat, and poaching. Extinction Textbook Reference pg. 115 http://www.chrismadden.co.uk/eco/mammoth.gif

29. Many scientists say that the earth is currently experiencing a mass extinction crisis. • It is estimated that 1/5 or more of the world’s species will become extinct if the rainforests alone are destroyed. Indian tigers, for example, are a group of tiger species that had an original range from India along Asia's Pacific rim to northern China as well as other sections of Central Asia. Their range today outside of protected areas has been severely limited. "Fragmented Habitat." Science Online. Facts On File, Inc. Web. 30 Jan. 2013. <http://www.fofweb.com/activelink2.asp?ItemID=WE40&SID=5&iPin=SciIllus04661&SingleRecord=True>.

30. There have been at least 5 mass extinctions during Earth’s history, when a huge % of the living species were destroyed. • At least one of these has been attributed to meteor impact and it’s consequences. • Animation Mass Extinction Textbook Reference pg. 378 Photo courtesy of Donald E. Davis, also in public domain from NASA.

31. Chicxulub Crater, Mexico's Yucatan Peninsula 180 kilometre (112 mi) diameter  Most scientists now agree that this event 65 million years ago that marked the sudden extinction of the dinosaurs as well as the majority of life then on Earth. Analyzing the Graphic

32. Evolutionary theory is constantly changingdue to new information that is obtained. • EX The AIDS virus is changing constantly,andthe flu vaccine must be modified each year due to changes. • Species change, evolve, over time, and that time is now. Conclusion http://evolution.berkeley.edu/evolibrary/images/news/avianswineflu.gif