Biogeography upload 2
Biogeography upload 2
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This 3 page Class Notes was uploaded by Brittany Yee on Tuesday September 20, 2016. The Class Notes belongs to at Kent State University taught by Dr. Brian Grafton in Fall 2016. Since its upload, it has received 33 views. For similar materials see Biogeography in Biological Sciences at Kent State University.
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Date Created: 09/20/16
Vagility- species are able to migrate by their own power. They are actively migrating Pagility- organisms disperse passively through wind, water, etc Abiotic seed dispersal organisms that disperse passively seeds get moved by environmental factors wind or water (Ex of water dispersal is coconuts) Biotic dispersal disperse seeds using animals fruit evolved to bribe a consumer of some sort to eat the seeds and then disperse them invertebrates can move great distances by “parachuting.” o Spiders can use their webs to catch wind currents and move great distances o Larvae can use ocean currents to move from one places to another o Large animals can be “rafted” from one place to another Barriers to dispersal Tend to be species specific Physiological- temperature, light, moisture o Ex: Puffins (birds that live only in the northern hemisphere). Similar looking to penguins. Dispersion is restricted by temperature barriers. Their barrier to dispersal is the tropics (temperature) o Ex: Right whale has amphitropical distribution. They have a distribution on either side of the tropics but stay out of tropic zones o Saltwater vs freshwater Ecological/physical- competitors/predators. May not find enough food to disperse through the area. If there are too many predators that prefer the organism that is moving it may never get there. o Physical barriers include mountains, rivers, deserts Dispersal routes 1) Corridor- the most generalized and open route. Least restricted kind of dispersal o Ex: land bridges (Bering land bridge and Panama land bridge) o The Sunda shelf between Thailand, Sumatra, and Borneo o Tethyan seaway 2) Filter- more restrictive. Not completely open and connected, so certain species cant move. o Arabian Peninsula- the only way between Africa and Asia. Because of climate differences in each area, there are restrictions to dispersion between both plants and animals 3) Sweepstakes- low probability of moving from one place to another. Happens completely by chance Establishing a colony Appropriate habitat Have to be able to reproduce and have viable offspring CHAPTER 7: SPECIATION AND EXTINCTION Ontogenetic relationships- individual metamorphasizes Tokogenetic relationships- relationships between individuals in a species Phylogenetic relationships- relative times in the past that species came from a common ancestor Cladogenesis- the evolution of 2 new species In asexual species- there is a linear conductivity. Very little connection between individual lineages because theyre not reproducing with eachother o Tend to be more isolated Species concepts Evolutionary Species Concept- an evolutionary species is a single lineage of ancestor- descendant populations which maintains its identity and has its own evolution tendencies o Morphology Morphological species concept- species are the smallest groups that are consistently distinct and distinguishable o Morphological- “type specimen” the first specimen that is observed that describes the species Doesnt take into account that species are variable (individual variation) Species are individually variable and geographically variable Biological species concept- species are groups of actually or potentially interbreeding natural populations that are reproductively isolated** from other groups o Reproductive isolation is the key concept. Kind of gets away from the concept of morphology Phylogenetic Species concept- a cluster of individuals that exhibit a pattern of phylogenetic ancestry o Monophyletic groups based on shared derived traits (synapomorphies) Subspecies- an aggregate of phenotypically similar populations of a species inhabitating a geographic subdivision of the range of the species and differing taxonomically from that species o Ex: deer mice- geographically and phenotypically distinct species based on their area, but they are all considered deer mice Levels of evolution Microevolution- gradual accumulation of genetic changes o Within species Macroevolution- accumulation of small changes over a long period of time. Creates a new species o Speciation Rates of evolution Gradualism- evolution occurs through gradual changes Punctuated equilibrium- species don’t change for a long period of time. Then there is an event that caused relatively rapid speciation o Partially explains gaps in the fossil record Forces of evolution Mutation- produces variation Gene flow- “evens out” variation Nonrandom mating- decreases heterozygosity Genetic drift- changes in allele frequencies by chance* o Reduces variation Natural selection- major force that produces new species by speciation
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