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Agenda

Agenda. Set Up DSJ / DSJ #2 Stamp Homework ( 22.2 notes) 22.2 presentation Group work - 22.2 concept check #1, 2 Notebook Art HW: Notes 23.1 and 23.3. Agenda. Set Up DSJ / DSJ #2 Stamp Homework ( 22.2 notes) 22.2 presentation Group work - 22.2 concept check #1, 2.

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Agenda

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  1. Agenda • Set Up DSJ / DSJ #2 • Stamp Homework (22.2 notes) • 22.2presentation • Group work - 22.2 concept check #1, 2 • Notebook Art • HW: Notes 23.1 and 23.3

  2. Agenda • Set Up DSJ / DSJ #2 • Stamp Homework (22.2 notes) • 22.2presentation • Group work - 22.2 concept check #1, 2

  3. DSJ #2 – DO ON PAGE 4 What is natural selection and how does it contribute to evolution?

  4. Chapter 22 Descent with Modification: A Darwinian View of Life

  5. Concept 22.2 • Essential knowledge: 1.a.1 Natural selection is a major mechanism of evolution

  6. England • EUROPE • NORTH • AMERICA • ATLANTIC • OCEAN • PACIFIC • OCEAN • Galápagos • Islands • HMS Beagle in port • AFRICA • SOUTH • AMERICA • Darwin in 1840, • after his return • AUSTRALIA • Cape of • Good Hope • Andes • Tasmania • Cape Horn • New • Zealand • Tierra del Fuego • Figure 22.5

  7. Darwin’s Focus on Adaptation • As Darwin reassessed all that he had observed during the voyage of the Beagle • He began to perceive adaptation to the environment and the origin of new species as closely related processes • Adaptations • New species

  8. From studies made years after Darwin’s voyage • Biologists have concluded that this is indeed what happened to the Galápagos finches • (a) Cactus eater. The long,sharp beak of the cactusground finch (Geospizascandens) helps it tearand eat cactus flowersand pulp. • (c) Seed eater. The large groundfinch (Geospiza magnirostris)has a large beak adapted forcracking seeds that fall fromplants to the ground. • Figure 22.6a–c • (b) Insect eater. The green warbler finch (Certhidea olivacea) uses itsnarrow, pointed beak to grasp insects.

  9. The Origin of Species • Darwin developed two main ideas • 1: Evolution explains life’s unity and diversity • 2: Natural selection is a cause of adaptive evolution

  10. Descent with Modification • The phrase descent with modification • States that all organisms are related through descent from an ancestor that lived in the remote past

  11. Sirenia • (Manatees • and relatives) • Loxodonta • africana • (Africa) • Elephas • maximus • (Asia) • Loxodonta • cyclotis • (Africa) • Hyracoidea • (Hyraxes) • the history of life is like a tree • Years ago • Stegodon • Mammut • Mammuthus • Deinotherium • Platybelodon • Millions of years ago • Barytherium • Moeritherium • Figure 22.7

  12. Observation #1: For any species, population sizes would increase exponentially • If all individuals that are born reproduced successfully • Figure 22.8

  13. Observation #2: Nonetheless, populations tend to be stable in size • Except for seasonal fluctuations • Observation #3: Resources are limited • Inference #1: Production of more individuals than the environment can support • Leads to a struggle for existence among individuals of a population, with only a fraction of their offspring surviving

  14. Observation #4: Members of a population vary extensively in their characteristics • No two individuals are exactly alike • Figure 22.9

  15. Observation #5: Much of this variation is heritable • Inference #2: Survival depends in part on inherited traits • Individuals whose inherited traits give them a high probability of surviving and reproducing are likely to leave more offspring than other individuals

  16. Inference #3: This unequal ability of individuals to survive and reproduce • Will lead to a gradual change in a population, with favorable characteristics accumulating over generations

  17. Artificial Selection • Lateral • buds • Terminal • bud • In the process of artificial selection • Humans have modified other species over many generations by selecting and breeding individuals that possess desired traits • Brussels sprouts • Cabbage • Flower • cluster • Leaves • Cauliflower • Kale • Flower • and • stems • Stem • Broccoli • Kohlrabi • Wild mustard • Figure 22.10

  18. Summary of Natural Selection • Natural selection is differential success in reproduction • results from the interaction between individuals that have different heritable traits and their environment

  19. (a) A flower mantidin Malaysia • Natural selection can produce an increase over time • In the adaptation of organisms to their environment • (b) A stick mantidin Africa • Figure 22.11

  20. If an environment changes over time • Natural selection may result in adaptation to these new conditions

  21. Group Work • In your groups, answer 22.2 concept check questions 1 and 2 in your notebook on pg. 7a

  22. Notebook Art • Using the textbook, find a chapter that seems interesting to you and copy one of the figures in that chapter

  23. Homework • take notes on 23.1 (454-458) and 23.3 (460-462) notebook pg. 8b • (yes you have an extra day to get these notes done! This does not happen often!!)

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