Chapter 15 Evolution PDF

Because learning changes everything. ® Chapter 15 Evolution FIFTEENTH EDITION James E. Bidlack, Shelly H. Jansky © 2021 McGraw Hill. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution perm...

Because learning changes everything. ® Chapter 15 Evolution FIFTEENTH EDITION James E. Bidlack, Shelly H. Jansky © 2021 McGraw Hill. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill.  Outline An Introduction to Evolution Evolution in Agriculture Evolutionary Medicine Species Extinctions and Invasions A Brief Overview of the Early Development of Evolutionary Concepts The First Revolution The Second Revolution The Third Revolution Charles Darwin Evidence for Evolution © McGraw Hill Stephen P. Lynch 2  Outline: MicroEvolution, Macroevolution, Role of Polyploidy, and Discussion Microevolution – Evolution within Species Natural Selection Mutations Migration Genetic Drift Rates of Evolution Macroevolution – How Species Evolve Geographic Isolation Ecological Isolation Mechanical Isolation The Role of Polyploidy in Evolution Discussion © McGraw Hill 3  An Introduction to Evolution Natural selection - Tendency of organisms with favorable adaptations to their environment to survive and produce new generations Theory proposed by Charles Darwin, 1859, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. Organic evolution - Accumulation of genetic changes in populations of living organisms through many changes Knowledge of evolutionary biology affects medicine, agriculture, forensics, biotechnology, economics, and law. © McGraw Hill 4  Evolution in Agriculture Humans have used artificial selection, or breeding, to change agricultural and domestic plants and animals. Artificial selection is used in plant and animal breeding; it is evolution directed by humans Without this application, humans could still be hunter-gatherers. Wild tomatoes have small fruits, but in domestication, plants with larger fruits were selectively bred. © McGraw Hill (a) © VOJTa Herout/Shutterstock (b) © Adrian Burke/Getty Images 5  Evolutionary Research Agricultural systems are agents of change by influencing evolution of native species. Example: insect populations evolving resistance to insecticides Agricultural entomologists study ways to prevent or delay evolution of pesticide resistance. © McGraw Hill 6  Evolutionary Medicine Evolutionary medicine applies evolutionary principles to the way in which we treat illness. Example: evolution of bacteria, unintentionally selecting for genetic ability to overcome antibiotics if antibiotics are not used properly Similar to insecticide resistance The application of evolutionary research involving discovery of natural compounds may be useful in medicine Can predict where to look for new products in relatives of useful plants Can look for plants that might have undergone selection pressure for those adaptations © McGraw Hill 7  Species Extinctions and Invasions Loss of species can undermine the health of entire ecosystems. Conservation biology uses evolutionary principles to understand species expansion or contraction in response to changing environments. © McGraw Hill 8  Species Invasions Species invasions impact ecosystems. Newly introduced species may displace native species. This is especially evident in Hawaii. 47 out of 100 of the most invasive species occur here. Kudzu is species introduced to the United States from Japan. It chokes out native vegetation. © McGraw Hill Tim Mainiero/Getty Images 9  Biotechnology and Evolution Evolutionary biologists determine fate of transgenes after genetically engineered crop plants are planted in fields. Transgenes - Foreign genes introduced into plants through genetic engineering A gene allows some crops to survive herbicides, which kill weeds. There is the potential for gene exchange between crop plants and their wild relatives This could result in herbicide resistant weeds. © McGraw Hill 10  A Brief Overview of the Early Development of Evolutionary Concepts Aristotle (384-322 BC) - Arranged organisms from simplest to most complex, called scale of nature Implied organisms static and do not evolve Leonardo da Vinci (1452-1519) - Observed that fossils part of previously existing organisms that had become extinct © McGraw Hill 11  View of Hereditary Changes By end of 18th century many prominent biologists believed that hereditary changes in populations over long periods of time occurred as a result of inheritance of acquired characteristics. Jean Baptiste Lamarck (1744– 1829) - Characters acquired during life were passed on and became cumulative. Believed that as giraffes stretched their necks those changes would be passed on to offspring. © McGraw Hill ©Kingsley Stern 12  Epigenesis Epigenetics is the study of heritable changes in gene expression not due to mutation. Can be accomplished by blocking gene expression via the additional of methyl groups to DNA. This can be reversed when gene products are needed. Occurs during development, typically reset during sexual reproduction. Can also be carried across generations May be a short-term adaptation that allows an organism to switch between phenotypes to respond changing environments This is an alternative to changes that result from mutation. Epigenetics provides a different explanation than that proposed by Lamarck. © McGraw Hill 13  Revolutions in Thought First revolution - Charles Darwin, On the Origin of Species, 1859 Evolution had been spoken of long before Darwin. His contributions were support for the idea of evolutionary change Natural selection, which is the proposed mechanism for how evolution works. Second revolution - 1930’s Theories of Darwinian natural selection, Mendelian genetics and population genetics intersected to provide better understanding of mechanisms of evolution. Third revolution - Now Evolution of development = “Evo-devo” Homeobox genes - Regulatory genes that act as developmental switches. Organisms with nearly identical genomes can look very different because different developmental programs created them. © McGraw Hill 14  Charles Darwin (1809–1882) Accepted unpaid position as assistant naturalist on HMS Beagle to voyage around the world and chart coastlines, 1831–1836 Read Charles Lyell’s geology book that theorized the earth was much older than previously believed Collected plants and animals in South America, in Galapagos Islands, in Australia and, in New Zealand Guided by ideas of Malthus, 1798 Populations grow geometrically until food supplies and other factors limit growth. Presented joint paper on natural selection with Alfred Wallace a year prior to publication of On the Origin of Species © McGraw Hill 15  Charles Darwin at Different Ages © McGraw Hill © Shutterstock/Everett Historica 16  Evidence for Evolution Homology - A characteristic shared by different organisms with common ancestry Convergent evolution - Similarities not due to common ancestry. Plants of different ancestry adapted in similar ways to common environmental conditions in different parts of world. Example: cactus and Cactus and Euphorbia, both adapted to arid Euphorbia habitats. © McGraw Hill ©Kingsley Stern 17  Other Evidence Structure and relationships of proteins, DNA, and other molecules; and common use of ATP Example: Some fundamental metabolism genes are universal Suggests early, single origin Fossil Record Simplest organisms are found in the oldest geological strata Geographical distribution Many groups are confined to a single continent or island © McGraw Hill ElementalImaging/Getty Images 18  Microevolution – Evolution within Species Darwin observed: Artificial selection - Changes in populations of domestic animals by retaining animals with desirable traits Limited supply of food and other resources prevents some individuals from reproducing. Competitive abilities of individuals vary within populations. Comparative anatomy and embryology He reasoned that individuals best adapted to utilize available resources would increase in number in succeeding generations. Natural selection - Descent with modification © McGraw Hill 19  Four Principles of Natural Selection 1. Overproduction of offspring 2. Struggle for existence - Competition for resources 3. Inheritance and accumulation of favorable variations 4. Survival and reproduction of fittest (differential survival and reproduction) Criticism of natural selection in Darwin’s time: natural selection did not explain how hereditary variations originated. © McGraw Hill 20  Mutation Mutation - Change in a gene or chromosome Deletion - Part of a chromosome breaks off. Translocation - Piece of chromosome becomes attached to another. Inversion - Part of chromosome breaks off and then reattaches in an inverted position. One or more nucleotide pairs changes. Most mutations are harmful; some silent or some produce characteristic that helps organism survive change. © McGraw Hill 21  Migration Migration - Gene flow between populations when individuals or gametes migrate from one population to another Depends on size of population and extent of isolation Genetic Drift - Changes in the genetic make-up of a population due to random events © McGraw Hill 22  Rates of Evolution Darwin believed evolution by natural selection was slow and gradual. A number of contemporary biologists believe theory of punctuated equilibrium. Major changes occurred in spurts of approximately 100,000 years followed by millions of years with minor change. Hypothesis based on fossils - Reveal large gaps in fossil record. © McGraw Hill 23  Macroevolution – How Species Evolve Geographic isolation Isolation of two populations prevents gene flow. Random mutations spread only throughout the population in which they arise. Genetic changes become so great that gene flow between populations no longer can occur. Eastern and western redbuds in the United States cannot survive in one another’s habitat. © McGraw Hill (b) ©Kingsley Stern 24  Ecological Isolation Ecological factors such as climate or soils may play role in isolation, as do time and mechanical isolating factors. Results in sympatric species that occupy overlapping ranges of territories, and that do not exchange genes Dutchman’s breeches and squirrel corn are closely related, but are also so distinct that they grow together without interbreeding. © McGraw Hill (a, b) Carol Wolfe, photographer 25  Mechanical Isolation Mechanical isolation Example: to reproduce, the pollinia of an orchid must fit into concave stigma Different species are so specific that is it unlikely that the pollinia of one species will fit into the stigma of another species. © McGraw Hill ©Kingsley Stern 26  The Role of Polyploidy in Evolution Polyploidy - Occurrence of double the normal chromosome number Result of failure of meiosis to halve chromosome number in gametes Polyploids produced when these gametes participate in fertilization. © McGraw Hill 27  Hybridization in Evolution Hybrids - Offspring produced by parents that differ in one or more characteristics Common in plants but not in animals May have gene combinations better suited to new environments Two related species may hybridize. Introgression - Intercrossing between hybrids and parents Hybrids often sterile because chromosomes do not pair properly at meiosis. If polyploid formed in hybrid, then chromosomes can pair and overcome sterility. © McGraw Hill 28  Alloploidy and Autoploidy Many domesticated crops are polyploid. Allopolyploid: a polyploid generated from an interspecific cross Autopolyploid: a polyploid formed from a single species Fireweed is an autopolyploid One subspecies is tetraploid One subspecies is octaploid © McGraw Hill ©Kingsley Stern 29  Apomixis Sterile hybrids may reproduce asexually. Apomixis - Production of seeds without fertilization. Combination of apomixis and sexual reproduction may be highly successful. Dandelions © McGraw Hill ©Shelley H. Jansky 30  Discussion Opinions and convictions about origin of life vary. Charles Darwin was not an atheist. He believed in a divine Creator that used natural laws to bring living things into being. The historical record is incomplete, so opposing arguments as to the relatedness of species can both be supported. Scientists can only deal with probabilities. © McGraw Hill 31 Because learning changes everything. ® www.mheducation.com © 2021 McGraw Hill. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill.