* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Natural Selection
Survey
Document related concepts
Dual inheritance theory wikipedia , lookup
Gene expression programming wikipedia , lookup
Public health genomics wikipedia , lookup
Human genetic variation wikipedia , lookup
Designer baby wikipedia , lookup
History of genetic engineering wikipedia , lookup
Genetic engineering wikipedia , lookup
Genome (book) wikipedia , lookup
Group selection wikipedia , lookup
Polymorphism (biology) wikipedia , lookup
Genetic drift wikipedia , lookup
Transitional fossil wikipedia , lookup
Koinophilia wikipedia , lookup
Transcript
Geography 210: Physical Geography and Environmental Issues Biodiversity Biogeography The Creation by Michelangelo Natural Selection • Organisms that have characteristics better suited to the environments they are in survive better, as do their offspring, given that the parents’ traits are inherited. – Taller giraffes, faster cats, smarter hunters, can get more food, survive – Pests become resistant to pesticides Idealized relation of an island’s size, distance from the mainland, and number of species. © 2003 John Wiley and Sons Publishers The main bio-geographic realms for animals are based on genetic factors. In each biogeographic realm, certain families or orders are dominant. © 2003 John Wiley and Sons Publishers The major vegetation realms are also based on genetic factors. © 2003 John Wiley and Sons Publishers Ocean Floor Spreading Plate Tectonics Continents in motion Divergent Evolution Ostrich – Africa Rhea – South America evolution from a common ancestor Evolution of Life on Earth • Past history from fossils and other stratigraphic deposits • Earliest beginnings: microorganisms • Early evolution was slow • 2 B y b p for 1st organisms. – Bacteria • 2-0.4 B y b p – the age of plants • 0.5 B y b p – first critters, mussels, trilobites • 0.2 B y b p – proto human Symbiosis “living together” Fig 7.8 The stomach of a reindeer illustrates complex symbiotic relationships. © 2003 John Wiley and Sons Publishers Succession Change in the relative abundance of a species over an area or a distance is referred to as an ecological gradient. © 2003 John Wiley and Sons Publishers Biogeographer, Dr. Keith H. Topps, Nipissing University, Ontario, Species Replacement at an Alpine Treeline, Top of the World Highway, Yukon, Canada All organisms are adapted to the environment in which they live Support: Fossils Support: Fossils •Earliest fossils were prokaryotes •Appeared in fossil record about 3.5 billion years ago Chronological Appearance of Vertebrates Support: Fossils Fossils link past and present Whales have forelegs in the form of flippers, however, they also have vestigial hind-leg and foot bones that do not extend from their body Support: Fossils Basilosaurus is an extinct whale that had hind-legs These also are vestigial legs as the ancient whale was an aquatic animal Other Support: Comparative Anatomy • Comparative Anatomy: comparison of body structures in different species • Anatomical similarities among many species give signs of common descent Other Support: Molecular Biology Artificial Selection German shepherd Yorkshire terrier English springer spaniel Hundreds to thousands of years of breeding (artificial selection) Ancestral dog Mini-dachshund Golden retriever Natural Selection African wild dog Coyote Fox Thousands to millions of years of natural selection Ancestral canine Wolf Jackal Natural Selection in Action Chromosome with gene conferring resistance to insecticide Insecticide application Additional applications of the same insecticide will be less effective, and the frequency of resistant insects in the population will grow Survivor Microevolution Chromosome with gene conferring resistance to insecticide Insecticide application Gene pool changes as most alleles that do not confer insecticide resistance are removed Survivor Causes of Microevolution • Bottleneck effect: genetic drift that results from event that drastically reduces population size Causes of Microevolution •Founder effect: random change in gene pool that occurs in a small colony of a population •A type of genetic drift •Over time, random changes in allele frequencies will continue until population is large enough that genetic drift is minimal Variation is extensive in populations 2 morphs of California King Snake