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Warm Up Question

Warm Up Question. Which of the following trophic levels is not shown in this diagram? producers decomposers primary consumers Where does the energy for this food web initiate? Plants Sun Rattlesnake. Darwin’s Theory: REVIEW…. 1. Organisms differ; variation is inherited

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Warm Up Question

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  1. Warm Up Question • Which of the following trophic levels is not shown in this diagram? • producers • decomposers • primary consumers • Where does the energy for this food web initiate? • Plants • Sun • Rattlesnake

  2. Darwin’s Theory: REVIEW…. 1. Organisms differ; variation is inherited 2. Organisms produce more offspring than survive 3. Organisms compete for resources 4. Organisms with advantages survive to pass those advantages to their children 5. Species alive today are descended with modifications from common ancestors

  3. Evidence for Evolution • 1. The Fossil Record: These imprints allow scientists to see an entire evolutionary history, including “in between” fossils. • 2. Homologous Body Structures: Why else use the same skeletal plan for very different appendages? • 3. Similarities in Embroyology: During the very early stages of life (in the womb), many organisms go through similar stages of development.

  4. Warbler finch Cactus eater Tree finches Ground finches Insect eaters Seed eaters Bud eater Darwin & Evolution by Natural Selection

  5. Charles Darwin • Proposed a way how evolution works • How did creatures change over time? by natural selection • Collected a lot of evidence to support his ideas • 1809-1882 • British naturalist

  6. Voyage of the HMS Beagle • Invited to travel around the world • 1831-1836 (22 years old!) • makes many observations of nature • main mission of the Beagle was to chart South American coastline Robert Fitzroy

  7. Voyage of the HMS Beagle • Stopped in Galapagos Islands • 500 miles off coast of Ecuador

  8. Galapagos Recently formed volcanic islands. Most of animals on the Galápagos live nowhere else in world, but they look like species living on South American mainland. 800 km west of Ecuador

  9. Darwin found…many unique species Many of Darwin’s observations made him wonder… Why? Darwin asked: Why were these creatures found only on the Galapagos Islands?

  10. present day Armadillos ancient Armadillo Darwin found…clues in the fossils Darwin found: Evidence that creatures have changed over time Darwin asked: Why should extinct armadillos & modern armadillos be found on same continent?

  11. present day Sloth (extinct) Giant ground sloth Darwin found… more fossils Darwin found: Evidence that creatures have changed over time

  12. Darwin found: Different shells on tortoises on different islands Darwin asked: Is there a relationship between the environment & what an animal looks like?

  13. Finch? Sparrow? Warbler? Woodpecker? Darwin found… birds Darwin found: Many different birds on the Galapagos Islands. He thought he found very different kinds… Finch? Sparrow? Warbler? Woodpecker?

  14. Finch? Sparrow? Warbler? Woodpecker? But Darwin found… a lot of finches Darwin was amazed to find out: All 14 species of birds were finches… But there is only one species of finch on the mainland! Large ground finch Small ground finch Finch? Sparrow? Darwin asked: If the Galapagos finches came from the mainland, why are they so different now? Warbler finch Tree finch Warbler? Woodpecker?

  15. Finch? Sparrow? Warbler? Woodpecker? The finches cinched it! • different beaks are inherited variations • serve as adaptationsthat help birds compete for food • these birds survive & reproduce • pass on the genes for those more fit beaks • over time nature selected for different species with different beaks Darwin found: The differences between species of finches were associated with the different food they ate. Darwin said: Ahaaaa! A flock of South American finches were stranded on the Galapagos… Large ground finch Big seed eater Small ground finch Small seed eater Warbler finch Insect eater Tree finch Leaf & bud eater

  16. Relationship between species (beaks) & food

  17. Darwin’s finches • Darwin’s conclusions • variations in beaks • differences in beaks in the original flock • adaptations to foods available on islands • natural selection for most fit • over many generations, the finches were selected for specific beaks & behaviors • offspring inherit successful traits • accumulation of winning traits:both beaks & behaviors • separate into different species

  18. Warbler finch Cactus finch Woodpecker finch Sharp-beaked finch Small insectivorous tree finch Small ground finch Warbler finch Large insectivorous tree finch Cactus eater Medium ground finch Tree finches Ground finches Insect eaters Seed eaters Large ground finch Vegetarian tree finch Bud eater From 1 species to 14 species… natural selection for best survival & reproduction variation

  19. Earlier ideas on Evolution • LaMarck • evolution by acquired traits • creatures developed traits during their lifetime • give those traits to their offspring • example • in reaching higher leaves giraffes stretch their necks & give the acquired longer neck to offspring • not accepted as valid

  20. Darwin’s view of Evolution • Darwin • giraffes that alreadyhave long necks survive better • leave more offspring who inherit their long necks • variation • selection & survival • reproduction & inheritance of more fit traits 

  21. Now let’s review!

  22. Review Questions: • Natural selection can best be defined as the _____. a. elimination of the smallest organisms by the biggest organisms b. survival of the biggest and strongest organisms in a population c. survival and reproduction of the organisms that are genetically best adapted to the environmentd. survival and reproduction of the organisms that occupy the largest area

  23. What type of adaptation is shown in the picture? a. homologous structure b. artificial selection c. camouflage d. mimicry

  24. How is natural selection in the evolution of long necks in giraffes best explained? • A Shorter-necked giraffes were killed by long-necked giraffes. • B Giraffe necks grew longer because of the bone structure of the animals. • C Giraffes with longer necks survived because they were better suited to the environment. • D Long-necked giraffes mated only with other long-necked giraffes.

  25. The diagram below shows a geologic cross section. Which rock layer most likely contains fossils of the most recently evolved organisms? • A 1 • B 2 • C 3 • D 4

  26. Which of the following explains why natural selection acts on the phenotype of an organism instead of its genotype? • A- Phenotypes directly influence the interaction of an organism with its environment. • B- Genotypes do not change except by the process of transcription. • C- Genotypes change in direct response to habitat changes. • D- Phenotypes can be inherited by offspring.

  27. Rainfall in a tropical region is below average for 10 consecutive years. Insect species adapted for dry conditions are much more plentiful at the end of the 10 years. Which of the following statements best explains the increase in the population of these insects? A- Biodiversity in the region has increased due to the dry conditions. B- Insects with a high tolerance for dry conditions have migrated out of the region. C- Natural selection has favored insect species with a high tolerance for dry conditions. D- Natural selection has selected against insect species that are adapted for dry conditions.

  28. The structures shown here are _______.a. analogous b. homologous c. vestigial d. heterologous

  29. Which of the following is a source of genetic variation within a species? A- cloning B- mutation C- selective breeding D- natural selection

  30. Skeletal structures are common between two animals of different species. These structures probably exist because both species A- have a common food source. B- live in the same environment. C- have survived until the present time. D- are related to a common ancestor.

  31. The diet of white-tailed deer consists primarily of shrubs. Sika are another species of deer that eat both grasses and shrubs. After an extended drought period, why might the sika population be favored over the white-tailed deer population? A- Sika require less food than do the white-tailed deer. B- Sika require more water than do the white-tailed deer. C- Sika have more food sources than do the white-tailed deer. D- Sika have fewer food sources than do the white-tailed deer.

  32. Darwin gathered his early evidence of evolution from __________ and especially noticed the remarkable differences in ___________. A- Galapagos Islands; Monkeys B- Galapagos Islands; Finches C- Galapagos Islands; Fish D- Hawaiian Islands; Fish

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