Homework. Antibiotic Resistance article and questions Study evolution flash cards for Vocab quiz on Friday!

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1 Homework Antibiotic Resistance article and questions Study evolution flash cards for Vocab quiz on Friday!

2 Learning Targets I can explain the theory of natural selection with an example. I can describe the process of speciation.

3 Class Data Period 6 Testtuberus 12 beans Tweezerus 17 beans Forcepius 12 beans Spoonius 20 beans Trial Start # Survived Survived Survived Survived Start # Start # Start # # % # % # % # % sec % % % % sec % % % % sec % % % % sec % % % % sec % % % % 1 1

4 Class Data - Combined Testtuberus 12 beans Tweezerus 17 beans Forcepius 12 beans Spoonius 20 beans Trial Start # Survived Survived Survived Survived Start # Start # Start # # % # % # % # % sec % % % % sec % % % % sec % % % % sec % % % % sec % % % %

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6 Survival of the Woolyboogers Analysis 4. Which beak type(s) became more common? Why? 5. Which beak type(s) became less common? Why? 6. While you were feeding, could you adapt and change your beak into a more desired variety? 7. If no individual changed their beak type, then how did the frequency of beak types change from the original population? 8. Darwin s theory of natural selection is sometimes called survival of the fittest. Explain what you think that means, based on what you learned from this activity.

7 1) Natural Selection The mechanism (driving force) for evolution, as explained by Charles Darwin. Explains changes in an entire species or population (not individuals) over time. 2) Mutations Random changes in DNA are sometimes passed on to offspring. Some helpful; some harmful; some neutral Only traits that increase reproductive fitness will continue to be passed on. Darwin knew this Darwin didn t know this because he didn t know about Genes and DNA

8 Darwin recognized that limited resources in any environment lead to a struggle for existence, in which the traits of some individuals will give them an advantage over others. However slight this advantage, it will lead to certain traits being selected by nature to survive and reproduce Hence, natural selection!

9 NATURAL SELECTION DEFINITION: the process by which organisms that are better suited to an environment survive and reproduce in greater number than those less suited. What causes natural selection? Environmental Change Survival of the Fittest (But what is fit????) Categorized into 5 Steps Whatever traits help you survive and/or reproduce

10 When we say competition Two men are walking through a forest. Suddenly, they see a tiger in the distance, running towards them. They turn and start running away. But then one of them stops, takes some running shoes from his bag, and starts putting them on. What are you doing? says the other man. Do you think you will run fast than the tiger with those? I don t have to run faster than the tiger, he says. I just have to run faster than you. who is competing with whom?

11 What is meant by fitness? Is this fitness?

12 STEP 1: Overproduction All species over reproduce creating a population with many variations (alleles) *the total of all alleles (or variations) in the population is called a gene pool

13 STEP 2: Inherited Variation Variations within a population come from mutations & random mating changing the populations gene pool MUTATIONS: Changes in an organisms DNA or genes (Darwin was missing this key info on genetics) RANDOM MATING: mixing of genes through reproduction A change in the gene for feather color creates different alleles which creates different coloration of bird feathers in the population VARIATIONS IN BIRD COLOR: Most birds are born with traits (genes) for being blue-green in color. Occasionally some birds are born with traits that make them more green. Occasionally some birds are born with traits that make them more blue.

14 STEP 3: Struggle to Survive Organisms compete for resources such as food, shelter, and mates. Those better suited to meeting these needs will survive. The birds face the challenge of blending in to survive.

15 STEP 3: Struggle to Survive Ugh!, so full Not all members of the species will survive this competition. Only some will survive and have the opportunity to pass on their successful genes. Since blue-green birds stand out more in the habitat than green birds, more blue-green birds are eaten EEP!

16 STEP 4: Successful Reproduction Successful traits are passed to the next generation. Now, more members of the population are being born with the successful variation than those with the less suited allele. This is how a species changes over time (evolves) How has the allele frequency in the population changed? Now more green chicks than blue/ blue-green are being born.

17 ? STEP 5: Adaptation of the Species (Not included in the textbook) Now the entire species becomes better suited to its environment. Hee, hee

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19 NATURAL SELECTION EXAMPLES Insecticide Resistance (textbook pg 123) Tuskless African elephants (textbook pg 122) Antibiotic Resistant Bacteria Sickle Cell Anemia and Malaria

20 On page 80 of your ISN Variation Different traits within a population or species; No two have the exact same DNA. Inheritance Selection Time Adaptation Traits are passed down from one generation to the next through genes. Certain traits are selected by nature because they help organisms survive and reproduce better than others. Given enough time over many generations, small, gradual changes become big changes. New beneficial traits arise as a population becomes suited to its environment, diet, and way of life.

21 SPECIATION (Steps to a new species) Speciation The formation of a new species by the change of allele frequency (genetic variation) due to natural selection. Species: a group of organisms that can interbreed and produce fertile offspring. 1. Separation: part of a population becomes isolated from the rest. What events could cause separation? 2. Adaptation: Natural selection improves the fit between species & environment created from changes in the gene pool. 3. Divergence: Enough differences accumulate no longer allowing the populations to interbreed, which leads to a NEW SPECIES.

22 Madagascar Examples of Speciation

23 Speciation Example Flightless Island Birds

24 Use VISTA to explain how giraffes evolved their long neck adaptation.