Evolution. What do we need to know? Biological evolution is due to: (1) genetic variability of offspring due to mutations and genetic recombination, (2) the potential for a species to increase its numbers, (3) a finite supply of resources, and (4) selection by the environment for those offspring better able to survive and produce offspring © 2011 Pearson Education, Inc

Evolution. What do we need to know? Random changes in the genetic makeup of cells and organisms (mutations) can cause changes in their physical characteristics or behaviors. If the genetic mutations occur in eggs or sperm cells, the changes will be inherited by offspring. While many of these changes will be harmful, a small minority may allow the offspring to better survive and reproduce. © 2011 Pearson Education, Inc

Evolution. What do we need to know? The great diversity of organisms is the result of more than 3.5 billion years of evolution that has filled available ecosystem niches on Earth with life forms. The fossil record and anatomical and molecular similarities observed among diverse species of living organisms provide evidence of biological evolution. © 2011 Pearson Education, Inc

Evolution. What do we need to know? Biological classifications are based on how organisms are related, reflecting their evolutionary history. Scientists infer relationships from physiological traits, genetic information, and the ability of two organisms to produce fertile offspring © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc Concept 22.1: The Darwinian revolution challenged traditional views of a young Earth inhabited by unchanging species Darwin’s ideas had deep biblical and historical roots © 2011 Pearson Education, Inc Modified Adams 2017.

Scala Naturae and Classification of Species The Old Testament holds that species were individually designed by God and therefore perfect  scala naturae (“scale of nature”). Categorized all organisms in order of “perfection.” © 2011 Pearson Education, Inc Modified Adams 2017.

Linnaeus and Adaptations interpreted adaptations as evidence that God had designed each species for a specific purpose Linnaeus was the founder of taxonomy, the branch of biology concerned with classifying organisms He developed the binomial format for naming species (for example, Homo sapiens) © 2011 Pearson Education, Inc Modified Adams 2017. .

Ideas About Change over Time © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc Paleontology, the study of fossils, was largely developed by French scientist Georges Cuvier Cuvier advocated catastrophism, speculating that each boundary between strata represents a catastrophe © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

James Hutton and Charles Lyell Geologists (Earth was more than 6000 years old) perceived that changes in Earth’s surface can result from slow continuous actions still operating today Lyell’s principle of uniformitarianism states that the mechanisms of change are constant over time This view strongly influenced Darwin’s thinking © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc Cuvier Developed the concept of Paleontology, the study of fossils Cuvier promoted catastrophism, speculating that each boundary between strata represents a catastrophe © 2011 Pearson Education, Inc Modified Adams 2017.

Ken Carpenter’s Dino Dig Camarasaurus Casting for transport to the Denver History Museum Rib bone and Vertebrae Allosaurus Group Shot The “Paleontology Shot”

© 2011 Pearson Education, Inc Cuvier Catastrophism, speculating that each boundary between strata represents a catastrophe © 2011 Pearson Education, Inc Modified Adams 2017.

© 2011 Pearson Education, Inc

Ideas About Change over Time Sedimentary rock layers (strata) Figure 22.3 Formation of sedimentary strata with fossils. Younger stratum with more recent fossils Older stratum with older fossils © 2011 Pearson Education, Inc

Lamarck’s Hypothesis of Evolution Lamarck hypothesized that species evolve through use and disuse of body parts and the inheritance of acquired characteristics The mechanisms he proposed are unsupported by evidence © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc Concept 22.2: Descent with modification by natural selection explains the adaptations of organisms and the unity and diversity of life Descent with modification is simply passing traits from parent to offspring, and this concept is one of the fundamental ideas behind Charles Darwin's theory of evolution. ... You pass traits on to your children in a process known as heredity. The unit of heredity is the gene. © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

Acquired traits cannot be inherited. Figure 22.4 Acquired traits cannot be inherited. © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc Figure 22.5 The voyage of HMS Beagle. Darwin in 1840, after his return from the voyage HMS Beagle in port Great Britain EUROPE NORTH AMERICA ATLANTIC OCEAN The Galápagos Islands AFRICA PACIFIC OCEAN Pinta Genovesa Equator Marchena Malay Archipelago Equator SOUTH AMERICA PACIFIC OCEAN Santiago Daphne Islands Chile Brazil AUSTRALIA Fernandina Pinzón PACIFIC OCEAN Andes Mtns. Figure 22.5 The voyage of HMS Beagle. Isabela Santa Cruz Cape of Good Hope Santa Fe San Cristobal Argentina Tasmania 20 40 Florenza Española Cape Horn Kilometers New Zealand © 2011 Pearson Education, Inc

Darwin saw organisms adapted to their environment (a) Cactus-eater (b) Insect-eater Three examples of beak variation in Galápagos finches Figure 22.6 Three examples of beak variation in Galápagos finches. © 2011 Pearson Education, Inc (c) Seed-eater

Overview: That “Mystery of Mysteries” In the Galápagos Islands Darwin discovered plants and animals found nowhere else on Earth © 2011 Pearson Education, Inc.

Figure 24.1 How did this flightless bird come to live on the isolated Galápagos Islands? Figure 24.1 How did this flightless bird come to live on the isolated Galápagos Islands?

© 2011 Pearson Education, Inc In 1844, Darwin wrote an essay on natural selection as the mechanism of descent with modification, but did not introduce his theory publicly Natural selection is a process in which individuals with favorable inherited traits are more likely to survive and reproduce © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc The Origin of Species Darwin explained three broad observations: The unity of life The diversity of life The match between organisms and their environment © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc The gist: Darwin noted that current species are descendants of ancestral species Evolution can be defined by Darwin’s phrase descent with modification (refers to the view that all organisms are related through descent from an ancestor that lived in the remote past) Evolution can be viewed as both a pattern and a process © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc In the Darwinian view, the history of life is like a tree with branches representing life’s diversity Darwin’s theory meshed well with the hierarchy of Linnaeus © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

Descent with modification Hyracoidea (Hyraxes) Sirenia (Manatees and relatives) †Moeritherium †Barytherium †Deinotherium †Mammut †Platybelodon †Stegodon †Mammuthus Figure 22.8 Descent with modification. Elephas maximus (Asia) Loxodonta africana (Africa) Loxodonta cyclotis (Africa) 60 34 24 5.5 2 104 Millions of years ago Years ago © 2011 Pearson Education, Inc

Now, Darwin has to make an argument… © 2011 Pearson Education, Inc

Here are some common observations and inferences: © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc Descent with modification came from a couple particular observations and inferences: Observation #1: Members of a population often vary in their inherited traits © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc Inference #1: Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment will produce more offspring than other individuals © 2011 Pearson Education, Inc Modified Adams 2017.

© 2011 Pearson Education, Inc Observation #2: All species can produce more offspring than the environment can support, and many of these offspring fail to survive and reproduce © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc Inference #2: This imbalance of individuals to survive and reproduce leads to the accumulation of favorable traits in the population over generations © 2011 Pearson Education, Inc Modified Adams 2017.

© 2011 Pearson Education, Inc What happens at intersection? © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc An example of adaptation: Camouflage as an example of evolutionary adaptation Figure 22.12 Camouflage as an example of evolutionary adaptation. (a) ? (b) ? © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc An example of adaptation: Camouflage as an example of evolutionary adaptation Figure 22.12 Camouflage as an example of evolutionary adaptation. (a) A flower mantid in Malaysia (b) A leaf mantid in Borneo © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc Note: that individuals do not evolve; populations evolve over time Note: Natural selection can only increase or decrease passed traits that already exist and vary in a population © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc Concept 22.3: Evolution is supported by an overwhelming amount of scientific evidence Evidence continues to fill the gaps identified by Darwin in The Origin of Species © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

Evidence type 1: Direct Observations of Evolutionary Change Two examples provide evidence for natural selection: natural selection in response to introduced plant species, and the evolution of drug-resistant bacteria © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc Figure 22.13a Can a change in a population’s food source result in evolution by natural selection? FIELD STUDY Figure 22.13 Inquiry: Can a change in a population’s food source result in evolution by natural selection? Soapberry bug with beak inserted in balloon vine fruit © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc Can a change in a population’s food source result in evolution by natural selection? RESULTS Beak 10 On native species, southern Florida 8 6 4 2 Number of individuals Museum-specimen average 10 8 On introduced species, central Florida Figure 22.13 Inquiry: Can a change in a population’s food source result in evolution by natural selection? 6 4 2 6 7 8 9 10 11 Beak length (mm) © 2011 Pearson Education, Inc

The Evolution of Drug-Resistant Bacteria The bacterium Staphylococcus aureus is commonly found on people One strain, methicillin-resistant S. aureus (MRSA) is a dangerous pathogen S. aureus became resistant to penicillin in 1945, two years after it was first widely used S. aureus became resistant to methicillin in 1961, two years after it was first widely used © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc Methicillin works by inhibiting a protein used by bacteria in their cell walls MRSA bacteria use a different protein in their cell walls When exposed to methicillin, MRSA strains are more likely to survive and reproduce than nonresistant S. aureus strains MRSA strains are now resistant to many antibiotics © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

Chromosome map of S. aureus clone USA300 Figure 22.14 1 2,750,000 250,000 base pairs 2,500,000 Chromosome map of S. aureus clone USA300 500,000 2,250,000 Key to adaptations Methicillin resistance Ability to colonize hosts 750,000 Increased disease severity 2,000,000 Increased gene exchange (within species) and toxin production Figure 22.14 Impact: The Rise of MRSA 1,000,000 1,750,000 1,250,000 1,500,000 © 2011 Pearson Education, Inc

Evidence type 2: Homology Homology is similarity resulting from common ancestry © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

Anatomical and Molecular Homologies Homologous structures are anatomical resemblances that represent variations on a structural theme present in a common ancestor © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc Figure 22.15 Humerus Radius Ulna Carpals Metacarpals Figure 22.15 Mammalian forelimbs: homologous structures. Phalanges Human Cat Whale Bat © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc Figure 22.16 Comparative embryology reveals anatomical homologies not visible in adult organisms Pharyngeal pouches Post-anal tail Figure 22.16 Anatomical similarities in vertebrate embryos. Chick embryo (LM) Human embryo © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc Vestigial structures and genes have no apparent function and appear to be residual parts from a past ancestor Examples: human appendix, the pelvic bone of a snake, and the wings of flightless birds. Can become disadvantageous, but in most cases these structures are harmless; however, these structures, like any other structure, require extra energy and are at risk for disease. Vestigial structures, especially non-harmful ones, take a long time to be phased out since eliminating them would require major alterations that could result in negative side effects. © 2011 Pearson Education, Inc Modified Adams 2017

Tree thinking: hypotheses of evolutionary relationships. Branch point Lungfishes Amphibians 1 Tetrapods 2 Mammals Digit- bearing limbs Amniotes 3 Lizards and snakes Amnion 4 Crocodiles Homologous characteristic Figure 22.17 Tree thinking: information provided in an evolutionary tree. 5 Ostriches 6 Birds Feathers Hawks and other birds © 2011 Pearson Education, Inc

Evidence type 3. The Fossil Record The fossil record provides evidence of the extinction of species, the origin of new groups, and changes within groups over time © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

© 2011 Pearson Education, Inc Figure 22.19 Most mammals Cetaceans and even-toed ungulates Figure 22.19 Ankle bones: one piece of the puzzle. (a) Canis (dog) (b) Pakicetus (c) Sus (pig) (d) Odocoileus (deer) © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc Figure 22.UN01 Figure 22.UN01 In-text figure, p. 465 © 2011 Pearson Education, Inc

© 2011 Pearson Education, Inc Other even-toed ungulates Hippopotamuses †Pakicetus †Rodhocetus Common ancestor of cetaceans †Dorudon Figure 22.20 The transition to life in the sea. Living cetaceans 70 60 50 40 30 20 10 Key Pelvis Tibia Millions of years ago Femur Foot © 2011 Pearson Education, Inc

Evidence type 4. Biogeography Biogeography, the geographic distribution of species, provides evidence of evolution © 2011 Pearson Education, Inc © 2011 Pearson Education, Inc.

Speciation, the origin of new species, is at the focal point of evolutionary theory Evolutionary theory must explain how new species originate and how populations evolve Microevolution consists of changes in allele frequency in a population over time Macroevolution refers to broad patterns of evolutionary change above the species level © 2011 Pearson Education, Inc.

Animation: Macroevolution Right-click slide / select “Play” © 2011 Pearson Education, Inc.