Evolutionary Theories

2. Are all of Lamarck’s hypotheses currently supported? 1. Describe 1 of Lamarck’s hypotheses 2. Are all of Lamarck’s hypotheses currently supported? 3. List 2 observations Darwin made on his voyage on the Beagle 4. In what way did Lyell influence Darwin? 5. In what way did Malthus influence Darwin?

Darwin’s journey (continue this after the reading quiz) Charles Darwin (1809-1882) sailed on the HMS Beagle in 1831 Observed huge diversity 2 questions: Where did all of these new species come from? Why have so many disappeared?

Darwin’s evidence and inferences 1. All species produce far more offspring than required just to replace parents. This would result in exponential growth if populations were not limited. ("Essays on Population" by Thomas Malthus) 2. Populations do not, however, increase exponentially. They generally remain stable in size. (Field observations) 3. The resources in the environment are limited. (Field observations) 1. Because of the limited resources in the environment, there is competition among individuals. Only a small fraction of the individuals born can survive.

Darwin’s evidence and inferences 4. There is variation within species and populations. Some individuals possess characteristics that are better suited to the environment than others. (Field observations) 5. Most physical, and some behavioral characteristics are inherited. (Breeding experiments with pigeons. "Artificial selection") 2. Those individuals with the best characteristics for the particular environment will do a better job of producing and providing for offspring than will others with less "fit" characteristics.

Darwin’s evidence and inferences 6. Geologic processes are very, very slow. (Principles of Geology by Charles Lyell, work by Hutton, as well as Darwin's own studies of geology) 3. The earth must be very, very old. Over very great periods of time, "good" characteristics have time to accumulate and less fit ones have diminished.

Reading quiz: 8-23/24 (have timeline and assignment sheet at your desk ready to be stamped) 1. Define adaptation 2. Define natural selection 3. Is natural selection the same thing as evolution? Explain. 4. List 2 of Darwin’s points about his theory of evolution

Reading quiz: 8-23/24 1. Define adaptation 2. Define natural selection Inherited trait that provides a selective advantage (increases fitness) 2. Define natural selection Differential rate of reproduction (or survival of the fittest organisms) 3. Is natural selection the same thing as evolution? Explain. NO! Evolution refers to changes of a population over time. Natural selection is the mechanism that can drive evolution 4. List 2 of Darwin’s points about his theory of evolution Variation within a species exists, some species are better suited to survive, favorable traits (adaptations) tend to spread in a population, living species evolved from organisms (descent)

Natural Selection There is variation in all species Some variation better adapted for the environment than others Natural selection (survival of the fitter): Individuals with characteristics better adapted for the environment will survive and have more viable offspring than non adapted individuals.

Lamarck’s evidence and inference Comparisons between current species and fossils: lines of descendents Use and disuse Inheritance of acquired characteristics

What exactly is a theory? Explain which picture describes Lamarck’s view and which pictures describes Darwin’s view.

1. Define a vestigial structure 2. Define a homologous structure Reading quiz: 8-25 (pass SG 4 and assignment sheet to the center. Natural selection lab will be collected at the end of class) 1. Define a vestigial structure 2. Define a homologous structure 3. Give an example of a homologous structure (description, not picture) 4. Describe how proteins can be used to show relationships among species 5. What is 1 limitation of using proteins to compare species

Evidence for evolution

Evidence for evolution Homologous structure: Provides evidence for common ancestor (note: Humans did NOT evolve from apes, but rather a common ancestor Vestigial structures Embryo similarities Biochemical similarities

Reading quiz: 8-28/29 1. According to the most current scientific evidence, how old is the earth? 2. We have found fossils of fish and amphibians. What did Darwin predict would eventually be found? 3. Define a fossil 4. List 2 ways fossils can form

Forming a deduction Remember these terms… Hypothesis, experiment, prediction A deduction combines all three. It is a very formalized way to guide an experiment. IF hypothesis AND experiment THEN prediction We are interested whether males or females are better at biology IF _____ AND ___ THEN ___ .

Fossils Remains or impressions of organisms preserved, either in tar, sap, sedimentary rock or other Are the remains of all organisms preserved? Do scientists have all of these remains? What can the fossil record tell us?

How do species arise? Must be reproductively isolated. This develops from Behavioral isolation Geographic isolation Temporal isolation

Darwin’s finches Founders arrive Separation of population Variation arises Reproductive isolation Ecological competition Continued evolution

New species case study You have just discovered 2 new populations of birds living in the Amazon Rain Forest. Although they look the same, they seem to sing different songs. You first want to know whether these 2 groups are different species or not. How do you decide? You find out that they are separate species. Propose an explanation for how this speciation occurred. Be creative and use all the vocabulary learned in class, evolution natural selection speciation, etc.

Reading quiz: 8-30/31 1. Define reproductive isolation 2. Define punctuated equilibrium 3. List 2 points of Darwin’s theory of evolution (natural selection) 4. Define speciation

Reading quiz: 8-30/31 1. Define reproductive isolation When 2 groups of organisms cannot interbreed (reproduce with each other) 2. Define punctuated equilibrium Theory in which periods of rapid evolution is separated by periods of little/no change 3. List 2 points of Darwin’s theory of evolution (natural selection) Variation within a species exists, overpopulation, some species are better suited to survive, favorable traits (adaptations) tend to spread in a population, living species evolved from organisms (descent) 4. Define speciation The process of forming new species

Another example of evolution Bacterium Mycobacterium tuberculosis infects individuals and causes the lung disease TB Antibiotics created to kill the bacteria New strains (variations) appeared. How?

Another example of evolution Bacterium Mycobacterium tuberculosis infects individuals and causes the lung disease TB Antibiotics created to kill the bacteria New strains (variations) appeared. How? A change randomly occurs in the bacteria Variations exist Non resistant bacteria die Antibiotic resistant strain thrives!

Patterns of evolution jigsaw Topics Punctuated equilibrium (282) Adaptive radiation (Divergent evolution) (handed out) Convergent evolution (307) Coevolution (handed out) First go through topic with group. Use textbook and study guide. Takes notes on your discussion. UNDERSTAND YOUR TOPIC! Create a poster to visually display your topic. This should have the topic title, picture(s), and key points. You will rotate explaining your topic to others and listening to others explain their topic. TAKE NOTES!

Practice essay question Support the following statement by clearly defining terms, explaining relationships, and giving examples. The evolutionary theories of Lamarck and Darwin differed, yet had commonalities.

Rubric Does the response… Describe the following points (inferences) about Darwin’s theory – variation within species, competition, survival of the fittest organisms, inheritance of adaptations Describe the following points (inferences) about Lamarck’s theory – use and disuse, inheritance of acquired characteristics Clearly states differences in these descriptions Clearly states commonalities in these descriptions Gives an example of each Use the following format IF ___ AND ___ THEN Provides a tentative, testable explanation after IF Provides a general description of the lab after AND Provides a measurable prediction after THEN (such as more prey will survive or # of prey living)

How do I study? Study frequently, differently, and actively You are given the opportunity to succeed and get any grade you want. It is up to YOU to do this and earn your grade What NOT to do Only study the night before or study not at all Simply reread information (textbook, etc.) Study in only one way What TO DO Review notes and work EVERY day, and even more DAYS before an exam While reviewing study guide, labs, worksheets, and textbook, keep asking yourself “do I understand this” and keep writing down notes, making outlines, answering questions Do different things. Flash cards, end of the chapter questions, draw out diagrams Study with a group, attend review sessions, see ME for help!

How to study First assess yourself (be metacognitive) For each study guide question, mark it with a +, √, or – Focus more on your (–) and (√) questions. Use study guide and notes a primary reference (textbook as last resort).