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Welcome to SCI 204, Environmental Science Biodiversity (Continuation) In this presentation we look at the dynamics of Biodiversity including 1.Natual Selection.

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Presentation on theme: "Welcome to SCI 204, Environmental Science Biodiversity (Continuation) In this presentation we look at the dynamics of Biodiversity including 1.Natual Selection."— Presentation transcript:

1 Welcome to SCI 204, Environmental Science Biodiversity (Continuation) In this presentation we look at the dynamics of Biodiversity including 1.Natual Selection 2.Biological Evolution 3.Ecological Succession 4.Natural History 5.Geologic Time

2 How does nature sustain ecosystems? Nature sustains ecosystems by promoting a maximum of species variety (or biodiversity) across with the system, including 1.Maximum population within a species within a habitat 2.Maximum number of different species within a habitat There are four processes which explain how biodiversity is accomplished 1.Natural selection 2.Biological evolution 3.Ecological succession 4.Extinction

3 Anaticipated Blend Of Population vs Wilderness c 2050 What is Natural Selection? Natural Selection is the process by which 1.Particularly favorable traits within a species of a particular environment are promoted through the entire population 2.Beneficial genes, within a population, are reproduced in succeeding generations more than other others less beneficial genes 3.A population is made more adaptable to its environment than might otherwise be found 4.The variety of individuals within any single species can produce an entire new generation of the same species, with an equal or greater variety It is the process which governs how biodiversity in one generation Is passed on to the next

4 The first scientific observations of Natural Selection became popular when Charles Darwin published his observations of various popuations within the species of the galapagos islands.

5 What is Biological Evolution? Biological Evolution is a process by which 1.The change in genetic makeup within a population of species over successive generations 2.When change is great enough, the population can become an entirely new species 3.Evolution refers to the process whereby an entire population becomes differentiated from the existing or previous species Evolution is about differentiation among different populations and how these transform into new species.

6 How does Biological Evolution proceed? Biological Evolution is generally the product of genetic mutation caused by Random events within the replication of genetic code Chemicals or radiation which causes inheritable changes in the DNA molecules resulting in variant genes and qualities within a population Geographic isolation, where a population is isolated from other populations of the same species

7 Evidence of Evolutionary changes are often often visible in fossil records buried in sedimentary rock formations.

8 What is Ecological Succession? Ecological Succession is the process in which 1.Communities of species in a particular area become replaced over time by a series of different more complex species 2.The populations of plant and animal species change over time, usually to a greater more elaborate biodiversity 3.An area transforms from one ecological stage, with a partilcular diversity of species, to another Succession occurs from the introduction of exotic species, and/or populations alien to the indiginous populations native to the area

9 Current Blend of Population vs Wilderness c 2000 Ecological Succession transforms an ecosystem such that 1.Some populations and species dieback, even to the point of extinction 2.Other populations and species multiply by filling new and existing ecological niches 3.Ecosystems, decimated by the extinction of some species, acquire new populations to replace them It is often thought of in terms of a state of balance or equilibrium In nature which, when upest or disrupted, finds a new state. The continuous change of state makes the ecosystem dynamic. How does Ecological Succession proceed?

10 Ecological Succession is often times explained in terms of progressive ecological stage going from pioneer or primary stage through secondary and tertiary stages, to mature or climax stage.

11 How do Environmentalists use natural selection, evolution and ecological succession? An understanding of the effort by nature to expand biodiversity, and the processes for creating biodiversity helps wildlife managers 1.To recognize the health of an ecosystem 2.To develop strategies for protecting ecosystems 3.To design plans for expanding or creating ecosystems 4.To coordinate efforts to restore ecosystems which are under stress Knowledge of natural selection, biological evolution and ecological selection is at the heart of wildlife and land management

12 How are the Changes in the Biosphere Affected by Nature and/or Human Kind? Changes occurring in the biosphere can be generated from Natural causes Anthropogenic causes Changes occuring in the biosphere Do so over long periods of time On a global scale they are recorded over geologic time Are recorded as Natural History Are integrally connected with the atmospheric, geologic, and pedospheric changes which have occurred within an area

13 Natural changes may be caused by 1.Changes in climate () 2.Introduction of new species into an ecology () 3.Violent weather () Anthropogenic changes may include laws and regulations imposed 1.To protect an endangered or threatened species 2.To support soil conservation in the face of erosion or degradation 3.To promote organic farming and ranching practices as opposed to ecological reconstruction to support mechanized agriculture Example: How might a population of Pacific Coral be affected by natural changes? Pacific coral reefs can be reduced by temperature changes or salinity in the ocean water due to El Nino, new prediators can migrate in and decimate a Pacific coral reef, heavy Pacific storms can dislodge sections of Pacific coral reefs setting them adrift. Example: How might a population of Pacific Coral be affected by natural changes? Pacific coral reefs can be reduced by temperature changes or salinity in the ocean water due to El Nino, new prediators can migrate in and decimate a Pacific coral reef, heavy Pacific storms can dislodge sections of Pacific coral reefs setting them adrift.

14 What Are the Consequences of the Biosphere’s Changes on Civilization? Geologic time is recorded by Eons, Eras, and periods There are four Eons (or Ages) 1. Hadean million ya 2.Archean million ya 3.Proterozoic million ya 4.Phanerozoic 650 million ya to the present Within the Phanerozoic Eon there are Three Eras 1.Paleozoic (old life) million ya 2.Mesozoix (middle life) million ya 3.Cenozoic (present life)65 million ya to the present Within the Cenozoic Era there are Two periods 1.Paleogene (old period)65-23 million ya 2.Neogene (new period) million ya 3.Quaternary1.8 million ya to present


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