Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 14 How Biological Diversity Evolves PowerPoint® Lectures for Campbell Essential Biology, Fourth Edition – Eric Simon, Jane Reece, and Jean Dickey Campbell Essential Biology with Physiology, Third Edition – Eric Simon, Jane Reece, and Jean Dickey Lectures by Chris C. Romero, updated by Edward J. Zalisko © 2010 Pearson Education, Inc. © 2010 Pearson Education, Inc. What Is a Species? • The biological species concept defines a species as – “A group of populations whose members have the potential to interbreed and produce fertile offspring” • Species is a Latin word meaning: – “Kind” or – “Appearance.” © 2010 Pearson Education, Inc. PATTERNS OF EVOLUTION Nonbranching Evolution (no new species) Branching Evolution (results in speciation) Figure 14.1 Similarity between different species Diversity within one species Figure 14.2 Reproductive Barriers between Species Prezygotic barriers prevent mating or fertilization between species. Zygote Gametes Prezygotic barriers • Temporal isolation • Habitat isolation • Behavioral isolation • Mechanical isolation • Gametic isolation Viable, Postzygotic barriers fertile • Reduced hybrid viability offspring • Reduced hybrid fertility • Hybrid breakdown Figure 14.UN1 Temporal Isolation Skunk species that mate at different times Figure 14.4a Habitat Isolation Garter snake species from different habitats Figure 14.4b Behavioral Isolation Mating ritual of blue-footed boobies Figure 14.4c Mechanical Isolation Snail species whose genital openings cannot align Figure 14.4d Gametic Isolation Sea urchin species whose gametes cannot fuse Figure 14.4e POSTZYGOTIC BARRIERS Reduced Hybrid Viability Reduced Hybrid Fertility Hybrid Breakdown Horse Donkey Mule Figure 14.5 • Speciation or a new Species can form by: – Allopatric speciation, due to geographic isolation – Sympatric speciation, without geographic isolation © 2010 Pearson Education, Inc. Ammospermophilus harrisii Ammospermophilus leucurus Figure 14.7 Sympatric Speciation • Sympatric speciation occurs: – While the new species and old species live in the same time and place – If a genetic change produces a reproductive barrier between the new and old species © 2010 Pearson Education, Inc. What Is the Tempo of Speciation? • There are two contrasting models of the pace of evolution: – The gradual model, in which big changes (speciations) occur by the steady accumulation of many small changes – The punctuated equilibria model, in which there are – Long periods of little change, equilibrium, punctuated by – Abrupt episodes of speciation © 2010 Pearson Education, Inc. Punctuated model Time Graduated model Figure 14.10 Wing claw (like reptile) Teeth (like reptile) Feathers Long tail with many vertebrae (like reptile) Fossil Artist’s reconstruction Figure 14.11 • Bird wings are modified forelimbs that were previously adapted for non-flight functions, such as: – Thermal regulation – Courtship displays – Camouflage • The first flights may have been only glides or extended hops as the animal pursued prey or fled from a predator. © 2010 Pearson Education, Inc. Chimpanzee fetus Chimpanzee adult Human fetus Human adult (paedomorphic features) Figure 14.13 Figure 14.14 • Geologists have established a geologic time scale reflecting a consistent sequence of geologic periods. © 2010 Pearson Education, Inc. Domain Bacteria Earliest organisms Domain Archaea The protists (multiple kingdoms) Kingdom Plantae Domain Eukarya The three-domain classification system Kingdom Fungi Kingdom Animalia Figure 14.25 Ancestral mammal Monotremes (5 species) Extinction of dinosaurs Reptilian ancestor Marsupials (324 species) Eutherians (5,010 species) 250 200 150 100 65 50 0 Millions of years ago Figure 14.26a Table 14.1 Mass Extinctions © 2010 Pearson Education, Inc. Evolution Connection: Rise of the Mammals • Mass extinctions: – Have repeatedly occurred throughout Earth’s history – Were followed by a period of great evolutionary change © 2010 Pearson Education, Inc. • Fossil evidence indicates that: – Mammals first appeared about 180 million years ago – The number of mammalian species – Remained steady and low in number until about 65 million years ago and then – Greatly increased after most of the dinosaurs became extinct © 2010 Pearson Education, Inc. Hierarchical Classification Taxa Binomial species name: Dendroica fusca © 2010 Pearson Education, Inc. Difference between homologous and derived traits Homologous bones in forelimbs © 2010 Pearson Education, Inc. Wings are derived traits An example of convergent evolution Convergent Evolution of Wings Insects Birds Pterosaurs Bats © 2010 Pearson Education, Inc. • Fossils are reliable chronological records only if we can determine their ages, using: – The relative age of fossils, revealing the sequence in which groups of species evolved, or – The absolute age of fossils, requiring other methods such as radiometric dating © 2010 Pearson Education, Inc. • Radiometric dating: – Is the most common method for dating fossils – Is based on the decay of radioactive isotopes – Helped establish the geologic time scale © 2010 Pearson Education, Inc. Carbon-14 radioactivity (as % of living organism’s C-14 to C-12 ratio) Radioactive decay of carbon-14 100 75 50 25 0 0 5.6 11.2 16.8 22.4 28.0 33.6 39.2 44.8 50.4 Time (thousands of years) How carbon-14 dating is used to determine the vintage of a fossilized clam shell Carbon-14 in shell Figure 14.15 Plate Tectonics and Macroevolution • The continents are not locked in place. Continents drift about the Earth’s surface on plates of crust floating on a flexible layer called the mantle. • The San Andreas fault is: – In California – At a border where two plates slide past each other © 2010 Pearson Education, Inc. Figure 14.16 The Process of Science: Did a Meteor Kill the Dinosaurs? • Observation: About 65 million years ago, the fossil record shows that: – The climate cooled – Seas were receding – Many plant species died out – Dinosaurs (except birds) became extinct – A thin layer of clay rich in iridium was deposited © 2010 Pearson Education, Inc. • Question: Is the iridium layer the result of fallout from a huge cloud of dust that billowed into the atmosphere when a large meteor or asteroid hit Earth? • Hypothesis: The mass extinction 65 million years ago was caused by the impact of an extraterrestrial object. • Prediction: A huge impact crater of the right age should be found somewhere on Earth’s surface. © 2010 Pearson Education, Inc. • Results: Near the Yucatán Peninsula, a huge impact crater was found that: – Dated from the predicted time – Was about the right size – Was capable of creating a cloud that could have blocked enough sunlight to change the Earth’s climate for months © 2010 Pearson Education, Inc. Chicxulub crater Figure 14.18-3 CLASSIFYING THE DIVERSITY OF LIFE • Systematics focuses on: – Classifying organisms – Determining their evolutionary relationships • Taxonomy is the: – Identification of species – Naming of species – Classification of species © 2010 Pearson Education, Inc. Some Basics of Taxonomy • Scientific names ease communication by: – Unambiguously identifying organisms – Making it easier to recognize the discovery of a new species • Carolus Linnaeus (1707–1778) proposed the current taxonomic system based upon: – A two-part name for each species – A hierarchical classification of species into broader groups of organisms © 2010 Pearson Education, Inc. Naming Species • Each species is assigned a two-part name or binomial, consisting of: – The genus – A name unique for each species • The scientific name for humans is Homo sapiens, a two part name, italicized and latinized, and with the first letter of the genus capitalized. • Homo sapiens or Homo sapiens © 2010 Pearson Education, Inc. Classification: A Work in Progress • Linnaeus: – Divided all known forms of life between the plant and animal kingdoms – Prevailed with his two-kingdom system for over 200 years • In the mid-1900s, the two-kingdom system was replaced by a five-kingdom system that: – Placed all prokaryotes in one kingdom – Divided the eukaryotes among four other kingdoms © 2010 Pearson Education, Inc. Panthera pardus Leopard (Panthera pardus) Panthera tigris Panthera leo Tiger (Panthera tigris) Lion (Panthera leo) Panthera onca Jaguar (Panthera onca) Figure 14.19 • The taxonomic hierarchy extends to progressively broader categories of classification, from genus to: – Family – Order – Class – Phylum – Kingdom – Domain © 2010 Pearson Education, Inc. Species Panthera pardus Genus Panthera Leopard (Panthera pardus) Family Felidae Order Carnivora Class Mammalia Phylum Chordata Kingdom Animalia Domain Eukarya Figure 14.20 Classification and Phylogeny • The goal of systematics is to reflect evolutionary relationships. • Biologists use phylogenetic trees to: – Depict hypotheses about the evolutionary history of species – Reflect the hierarchical classification of groups nested within more inclusive groups © 2010 Pearson Education, Inc. Order Family Felidae Genus Species Panthera Panthera pardus (leopard) Mephitis Mephitis mephitis (striped skunk) Carnivora Mustelidae Lutra Lutra lutra (European otter) Canis latrans (coyote) Canidae Canis Canis lupus (wolf) Figure 14.21 The Cladistic Revolution • Cladistics is the scientific search for clades. • A clade: – Consists of an ancestral species and all its descendants – Forms a distinct branch in the tree of life © 2010 Pearson Education, Inc. Cladogram Iguana Outgroup (reptile) Duck-billed platypus Hair, mammary glands Gestation Kangaroo Ingroup (mammals) Beaver Long gestation Figure 14.23 Lizards and snakes Crocodilians Pterosaurs Common ancestor of crocodilians, dinosaurs, and birds Cladogram Ornithischian dinosaurs Saurischian dinosaurs Birds Figure 14.24 • In the late 20th century, molecular studies and cladistics led to the development of a three-domain system, recognizing: – Two domains of prokaryotes (Bacteria and Archaea) – One domain of eukaryotes (Eukarya) © 2010 Pearson Education, Inc.