–Varieties of life forms Figure 1.4C-F

All organisms have evolutionary adaptations –Inherited characteristics that enhance their ability to survive and reproduce blue-footed booby Large, webbed feet help propel the bird through water at high speeds Clown, Fool, or Well Adapted?

–A streamlined shape, large tail, and nostrils that close are useful for diving –Specialized salt-secreting glands manage salt intake while at sea

Charles Darwin synthesized the Theory of Evolution by natural selection –Theory vs hypothesis Evolution is the core theme of biology Evolution explains the unity and diversity of life Figure 1.6A

The voyage of the Beagle Figure 13.1B North America Great Britain Europe Africa Equator Australia Tasmania New Zealand Cape of Good Hope South America Andes Cape Horn Tierra del Fuego Galápagos Islands Pacific Ocean Atlantic Ocean

species are fixed Earth is about 6,ooo yrs old Prevalent ideas at Darwin’s time

New ideas proposed Fossils indicated the earth was very old Lyell, a geologist, argued that land forms changed constantly. Lamarck proposed that organisms changed and these changes were passed to progeny.

Darwin became convinced that the Earth was old and continually changing –He concluded that living things also change, or evolve over generations –He also stated that living species descended from earlier life-forms: descent with modification Mex. marine snail shells on high mtns

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Darwin observed that –organisms produce more offspring than the environment can support –organisms vary in many characteristics –these variations can be inherited Darwin proposed natural selection as the mechanism of evolution

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Darwin concluded that individuals best suited for an environment are more likely to survive and reproduce than those less well adapted –As a result, the proportion of individuals with favorable characteristics increases –Populations gradually change in response to the environment

natural selection explains the mechanism of evolution Figure 1.6B (1) Population with varied inherited traits (2) Elimination of individuals with certain traits (3) Reproduction of survivors Pesticide-resistant insects Antibiotic-resistant bacteria

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Charles Darwin, 1874 Figure 13.1x2

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Alfred Wallace Figure 13.1x6

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Darwin cartoon Figure 13.1x3

Evolution happens when populations of organisms with inherited variations are exposed to environmental factors that favor the reproductive success of some individuals over others –Natural selection is the editing mechanism –Evolution is based on adaptations Figure 1.6C

–Hominid skull Fossils provide strong evidence for evolution Figure 13.2A, B –Petrified trees

–Ammonite casts –Fossilized organic matter in a leaf Figure 13.2C, D

–Scorpion in amber –“Ice Man” – acid bogs Figure 13.2E, F

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Mammoth tusks Figure 13.2x4

fossils show that organisms have appeared in a historical sequence Many fossils link early extinct species with species living today –hind leg bones of fossil whales Figure 13.2G, H

–Biogeography –Comparative anatomy –Comparative embryology Other evidence for evolution Figure 13.3A HumanCatWhaleBat

–Molecular biology - protein “clocks” Figure 13.3B HumanRhesus monkeyMouseChickenFrogLamprey Last common ancestor lived 26 million years ago (MYA), based on fossil evidence 80 MYA 275 MYA 330 MYA 450 MYA

Figure 15.8 No predestined goal of evolution