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54 Cards in this Set
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A particular type of organism or, more precisely, a population or group of populations whose members share characteristics and can freely breed with one another a produce fertile offspring. |
Species |
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A group of individuals of a particular species that live in a particular area. |
population |
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Change over time in a biological evolution consisting of changes in populations of organisms across generations. |
Evolution: Founded by Charles Darwin and Alfred Russell Wallace |
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the process by which inherited characteristics that enhance survival and reproduction are passed on more frequently to future generations than those that do not, thus altering the genetic makeup of populations through out time. |
Natural Selection |
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The science that deals with the distribution and abundance of organisms, the interactions among them, and the interactions between organisms and their abiotic environment. |
Ecology |
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From one generation to another through time, characteristics, or traits, that lead to better and better reproductive success in a given environment will evolve in the population. |
adaptation or adaptive trait |
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What are accidental variations in DNA |
mutations |
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The process where very unrelated species may acquire similar traits as they adapt to selective pressures from similar environments |
Convergent evolution |
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Refers to the variety of life across all levels of biological organization, including the diversity of species, genes, populations and communities |
Biological diversity or biodiversity |
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The process by which new species are generated |
Speciation |
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Species that form from populations that become physically separated over some geographic distance |
allopatric speciation: can no longer bread with one another |
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The order for the circle of life |
biosphere ecosystems communities populations organisms cells molecules atoms |
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Premises for natural selection |
1. Organisms struggle to survive and reproduce 2. organisms produce more offspring than can survive. 3. individuals of species vary in their characteristics due to genes and the environment 4. some individuals are better suited to their environment and reproduce more efficiently |
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The process of selection directed under human direction |
artificial selection |
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What are the 3 modes of speciation? |
Allopatric: (allo = different, patria = homeland) Parapatric: (para = beside) Sympatric (sym = together) |
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Allopatric takes place in two steps |
1. Two populations become geographically separated, preventing gene flow between them. 2. Accumulated genetic differences isolate them re-productively. |
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Diagrams that show relationships among species, groups, genes etc. Explains how major groups of organisms came to be. |
Phylogentic Tree (the tree of life) |
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In imprint in stone of a dead organism |
Fossil |
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The cumulative body of fossils worldwide |
Fossil Record |
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Fossil records show |
1. Life on earth has be present for 3.5 billion years. 2. Earlier types of organisms evolved into later ones. 3. The number of species has increased over time. 4. Most species have gone extinct 5. There have been several mass extinctions in the past. |
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The disappearance of a species from earth |
Extinction |
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Factors that cause extinction |
1. Severe weather, climate change, change in sea levels. 2. Arrival of a new species 3. Being a small specialized species |
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A species that only exist in a certain, specialized area |
Endemic Species |
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5 Mass extinctions events |
§ Cretaceous-Paleogene § Triassic-Jurassic § Permian-Triassic § LateDevonian § Ordovician-Silurian |
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The surroundings where plants and animals live |
Habitat |
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Describes the functional position of an organism in its environment |
Ecological Niche: Specialization |
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Species that have narrow niches and specific needs |
Specialists |
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Species that have a broad niche and can live in many different places due to its wide array of uses in habitats and resources |
Generalist |
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Individuals of a particular species that inhabit and area |
Population |
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Number of individuals present at a given time |
Population size |
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The number of individuals in a population in a given area. |
Population density |
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5 key properties of a population |
1. Abundance 2. birth rate 3. death rate 4. growth rate 5. age structure |
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relyupon a high reproductive rate to overcome the high mortality of offspring with little or no parental care. Example: A clam releases a million eggs in a lifetime. |
r-selected species |
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havefew offspring, slower growth as they near carrying capacity and exercise more parental care. Example: An elephant only reproduces every 4 or 5years. |
k-selected species |
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Exiting your homeland |
Emigration |
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Coming into a country to live |
Immigration |
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expresses how population is divided among age groups |
Age structure |
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Whena few individuals start a new population, they carry only a small sample of theparent population’s genetic variation |
Founder effect: Example of genetic drift |
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Focuses on patterns of species diversity and on interactions among species. |
Community Ecology |
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Scientist who study human populations |
Demographers |
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limiting factors whose influence is not affected by population density |
density-independent factors |
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an event that drastically reduces the size of a population |
Populations Bottleneck |
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To show how the likelhood of survival varies with age, ecologist use a graphs call |
Survivorship curve |
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when multiple organisms seek the same limited resource |
competition |
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competition that takes place among members of the same species |
intraspecific competition |
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competition that takes place among members of different species |
interspecific competition |
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A species that has strong or wide-reaching impact far out of proportion to its abundance |
Keystone Species |
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Predators at high trophic levels can indirectly promote populations of organisms at lower trophic levels by keeping species at intermediate trophic levels in check |
trophic cascade |
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a community that resist change and remains stable despite disturbances |
resistant |
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a community that changes in response to disturbances but later returns to its original state |
resilience |
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when a disturbance is bad enough to eliminate all of most of the species in a community, the affected site may then a somewhat predictable series of changes |
succession |
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follows a disturbance so severe that no vegetation or soil life remains from the community that had occupied the site |
primary succession: a biotic community is built essentially from scratch |
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when a disturbance dramatically alters an existing community buy does not destroy all living things or all organic matter in the soil. |
secondary succession |
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species that arrive first and colonize the new substrat |
pioneer species |