Week 1 (Lecture 1 & 2) BIOL208
Week 1 (Lecture 1 & 2) BIOL208 BIOL 208
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This 3 page Class Notes was uploaded by Veronica Canarte on Friday September 2, 2016. The Class Notes belongs to BIOL 208 at Towson University taught by Christa R. Partain in Fall 2016. Since its upload, it has received 33 views.
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Date Created: 09/02/16
8/30/16 Lecture 1 Tuesday, August 30, 2011 What is biodiversity? Bio: - Life Diversity: - Living organisms - Different types - Anything - Taxonomic diversity biological - Different species - Components of biodiversity Species richness & diversity, genetic diversity, & phylogenetic diversity - genus + specific epithet = scientific name smallest Family Order 5 kingdom system is outdated: 3 Domain system is the "contemporary" approach From smallest to A) Bacteria Class largest B) Archaea C) Eukarya Phylum largest Domain • Biodiversity Crisis We are in out 6th mass extinction History of Extinctions: - Homo sapiens --> wreak havoc --> possibly caused extinction of 80% of the megafauna in North America Africa never experience Most likely because humans extinctions (like this) co-evolved with megafauna in Africa - Majority of extinctions have occurred on islands: Why? - Current mass extinction human A) organisms cannot leave the caused island Evidence: B) organisms are adapted to very A) exploitation specific environments B) pollution - "Hot spots" : concentrated endemic species that are rapidly disappearing (there are about 25 of them) Human population is on the rise in most of the hot spots : Why do we care? Biodiversity affects: A) pharmaceuticals B) food/crops C) clothing, biomass, etc Factors Responsible for Extinction: A) overexploitation C) loss of variation E)catastrophic disturbance B) habitat loss D) pollution Devastates a species # & abundance - Introduced species Outcompete and kill off native speces - Extinction cascade A cascade of extinctions (of other animals) Loss of a keystone species - Lack of genetic diversity difficult to comeback (recover) from disturbances Genetic drift in a small population • A chance deleterious allele widely affects small populations 9/1/16 Lecture 2 Thursday, September 1, 2016 - Life on earth: ○ Earth is ~ 4.6 billion years old Oldest geographical material (3.8 billion years old) shows sign of biological activity ○ • Plate tectonics Crust is dynamic & plates are moving over lava **** moving plates = • Movement of plates affects continental configuration more volcanic activity = more co2 in the environment Change in ocean Affects climate by changing ocean currents current = change in climate - Gondwana : where all the southern large land masses were - mega continent (India, Australia, South America, Africa) - Pangea: another super continent Major changes (in biodiversity, climate, etc) are believed to be the result of plate tectonics shifting This results in reproductive isolation, etc. - Cellular life: ○ Oldest cellular life is prokaryotic ○ 3 recognized major groups i. Bacteria ii. Archaea iii.Eukarya - Origin of Eukaryotes common idea that eukaryotes evolved by endosymbiosis Strongest support for this is evidence from chloroplasts & mitochondria - The Oxygen Revolution : about 2.3 billion years ago Oxygen was pretty non-existent for the first 2 billion year or so ○ The earliest photosynthetic organisms were/are cyanobacteria Oxygen revolution = changed the nutrient cycled This allowed for a great production of organic matter. Massive swamps formed, increased oxygen also allowed animals to grow larger. - Multi-cellular life : 1st seen well before beginning of Cambrian - What is a Species? There is no (1) definition for species; many accepted definitions Cambrian explosion : happens mid Cambrian; explosion of metazoans(animals) Assume that different species are unable to make (aka they C/N reproduce) Types of Definitions for Species: 1. Morphospecies - 2 populations that are statistically different by one/two physical characteristics 2. Chronospecies - "evolutionary species" ; a lineage constructed from fossil data that has been deemed as 2 species 3. Biological species concept - reproductively isolated interbreeding populations under natural conditions 4. Genotypic Cluster - the frequency of certain genotypes or phenotypes. No overlapping sequences (locus) between 2 species dictates separation (of the species) 5. Phylogenetic: Smallest detectable monophyletic populations within parental populations ; lineage has to be detectable.
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