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64 Cards in this Set
- Front
- Back
*SPECIES*
GEOGRAPHICAL ISOLATION example |
the Hawaiian Archipelago, which consists of numerous volcanic islands. Each island is physically diverse, allowing for natural selection to occur, which can lead to reproductive isolation. This type of allopatric speciation occured among honeycreepers (type of bird). There are over 20 living species of honeycreepers that all evolved from a single species that had colonized an island. Honeycreepers dispersed to the different islands and evolved. Those that came back to their native island were not capable of interbreeding with the natives anymore because the visiting honeycreepers had adapted to their new environment.
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*SPECIES*
How GEOGRAPHICAL SPECIATION happens? |
A geographic barrier arises, isolating the two populations. The newly isolated populations now go through a period of isolation. Some of the individuals within a population might exhibit a trait more suitable for the new environment. This variant allows for differential survivorship and reproduction. Those individuals that carry the trait are more likely to survive in the new environment. Therefore, they will leave more offspring. Gradually, the variant trait will become dominant. Theoretically, this would happen with both of the newly isolated populations resulting in reproductive isolation
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GEOGRAPHICAL SPECIATION
What happens if geographical barrier disappears but speciation already occurred |
The geographic barrier ends. The two populations now have the opportunity to interbreed again. If the populations do not recognize each other as potential mates or cannot produce fertile offspring, speciation has occurred because the populations are reproductively isolated. The two populations have become two different species. If speciation has not occurred, the populations can still interbreed successfully to produce viable, fertile offspring.
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Examples of ALLOPATRIC SPECIATION( which is always due to geographical isolation)
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Squirrels at Grand Canyon
Honecreepers birds on different Hawaiian islans House Mice brought Faroe islans and it became a separate species there |
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SPECIES
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A group of organisms which are capable of exchanging genes within the group but are genetically unable
to exchange genes in nature with other groups. New species form as a result of geographic isolation. (e.g., continental drift, different islands) Populations that are geographically isolated will diverge from one another genetically as a consequence of: 1) unique mutations 2) natural selection 3) genetic drift Migration interferes with evolution. In the absence of migration, genetic differences between populations become so great that the formation of hybrids becomes impossible. These biologically isolated populations are new species. |
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Define SELECTIVE PRESSURES
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Factors that determine if organism can survive and reproduce. Selctive pressures can favor on phenotype over another
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Define BIOLOGICAL FITNESS
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the ability to survive and reproduce, Biological fitness is not the same as physical fitness
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DIVERGENT v. CONVERGENT EVOLUTION
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DIVERGENT - occurs when different selective pressures act on population
CONVERGENT - same selective pressure acts on two different populations |
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DIVERGENT EVOLUTION
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--produces dissimilarities
--may cause speciation over time --produces homologous structures - same origin and diff function. Ex. Vertebrae - 4 limbs |
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CONVERGENT EVOLUTION
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--unrelated populations become more similar
--not exactly opposite from divergent evolution because they are not generally similar --produces ANALOGOUS structures - diff. origin, same function - Ex. Bat wing and flying squirrel |
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2 TYPES OF ISOLATION OF SPECIES
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Geographic and Reproductive
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REPRODUCTIVE ISOLATION--6 ways species may be isolated
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1) Cogeographic
2) Habitat 3) Time 4) Mechanical 5) Behavioral 6) Gametic Mating |
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REPRODUCTIVE ISOLATION
--6 ways species may be isolated 1) Cogeographic |
1) Cogeographic
Species have different ranges but no physical barriers. ex. Salamanders flickers |
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REPRODUCTIVE ISOLATION
--6 ways species may be isolated 2) Habitat |
2) Habitat
Habitat species in the same range but have different habitat Ex. Upland chorus frogs calls from open positions but southern chorus frogs call from places hidden in grass or debris |
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REPRODUCTIVE ISOLATION
--6 ways species may be isolated 3) Time |
3) Time
-Nocturnal v. diurnal (day v night) -differnet breeding seasons Ex. American toad breed early in the season and fowler toad later |
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*SPECIES*
What happens if geographical barrier disappears but speciation already occurred |
The geographic barrier ends. The two populations now have the opportunity to interbreed again. If the populations do not recognize each other as potential mates or cannot produce fertile offspring, speciation has occurred because the populations are reproductively isolated. The two populations have become two different species. If speciation has not occurred, the populations can still interbreed successfully to produce viable, fertile offspring.
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*SPECIES*
Examples of ALLOPATRIC SPECIATION( which is always due to geographical isolation) |
Squirrels at Grand Canyon
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*SPECIES*
What is continuous variation? |
a trait that's controlled by several genes and exhibits a variety of phenotypes a genetic phenomenon.
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*SPECIES*
What is TAXONOMY? |
The classification of animals and plants.
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*SPECIES*
REPRODUCTIVE ISOLATION --6 ways species may be isolated 4) Mechanical |
4) Mechanical
Physically dont fit together - more common in plants |
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REPRODUCTIVE ISOLATION
--6 ways species may be isolated 5) Behavioral |
5) Behavioral
different mating rituals ex. differnet breeding calls, color preferences to choose their type -more commmon in animals |
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REPRODUCTIVE ISOLATION
--6 ways species may be isolated 6) Gametic mating |
6) Gametica mating occurs but a) viable fertile offspring are not produced
b) sperm never reaches egg -biologically expensive (wasted gametes) It prevents cross breeding, The offspring is sterile. |
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SPECIES
VARIATION about |
selective pressures will not cause speciation unless there is inherited variation in the species
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*SPECIES*
SPECIES VARIATION TYPES and SOURCES list |
TYPES:
1) Discontinuos variation 2) continuous variation SOURCES: -Different Genes -environmentally induced |
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*SPECIES*
SPECIES VARIATION Types: DISCONTINUOUS VARIATION |
Discontinuous variation - POLYMORPHISM
--2 or more distinct forms of a species --there are ni intermediates ex. snow goose, red+yellow flickers RR Rr rr |
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*SPECIES*
POLYMORPHISM is the same as |
DISCONTINUOUS VARIATION
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*SPECIES*
SPECIES VARIATION Types: CONTINUOUS VARIATION |
--intermediate forms are present
Ex. carnations red+white=pink, most dog species |
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*SPECIES*
SPECIES VARIATION Sources: 1) DIFFERENT GENES 2) ENVIRONMENTALLY INDUCED |
1) DIFFERENT GENES
-mutation -breeding through sexusal reproduction (recombination) 2) ENVIRONMENTALLY INDUCED |
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*SPECIES*
NATURAL SELECTION What must be present to Natural selection to occur? |
--Variation must be present in a population for natural selection to occur
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*SPECIES*
PROGENY = |
OFFSPRING
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*SPECIES*
NATURAL SELECTION HOw biological fitness is determined? |
--biological fitness is determined by the relative numbers of the reproducing offspring
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*SPECIES*
NATURAL SELECTION general points |
--If an organism can survive and reproduce, it will leave its genetic informaiton in the next generation
--Survival of the best adapted |
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*SPECIES*
NATURAL SELECTION 3 types |
1) Stabilizing selection
2) DIrectional selection 3) Disruptive selection |
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*SPECIES*
NATURAL SELECTION 1) Stabilizing selection |
1) Stabilizing selection
--Selects against extermes and for the middle common --occurs during times of change |
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*SPECIES*
NATURAL SELECTION 2) Directional Selection |
- Selects againt one extreme
- is common -occurs during the times of change |
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*SPECIES*
NATURAL SELECTION 3) Disruptive selection |
-selecting against the middle and for both extreme
-uncommon occurs during times of change -can lead to speciation |
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*SPECIES*
POLYMORPHISM |
many forms
occurence of several distinct forms of a species Causes: 1) differences in major genes 2) envoronmentally induced |
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*SPECIES*
TRANSIENT POLYMORPHISM |
disadvantageous allele becomes advantageous ex. peppered moth
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*SPECIES*
LEVELS OF ORGANIZATION - list only |
1 individual organism
2 species 3 population 4 community 5 ecosystems 6 biosphere |
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*SPECIES*
WHAT IS ECOLOGY |
the study of the interations between organisms and their environment
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LEVELS OF ORGANIZATION
BIOSPHERE |
What three things make up the biosphere? top portion of Earth's crust, all waters, the atmosphere
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LEVELS OF ORGANIZATION
ECOSYSTEM |
All living organisms and the physical environment on which they depend
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*SPECIES*
LEVELS OF ORGANIZATION COMMUNITY |
All the species living close enough to interact with each other
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*SPECIES*
LEVELS OF ORGANIZATION POPULATION |
individulas of the same species in the same area that constitute an internbreeding and reproducing group
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*SPECIES*
LEVELS OF ORGANIZATION SPECIES |
individulas that able to interbreed and produce viable fertile offspring
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*SPECIES*
TAXONOMY MORPHOLOGICAL SPECIES CONCEPT I |
Mor. Sp. concept separated groups by physical differences and appearance
Used by classical taxonomist associated with Carl von Linne |
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TAXONOMY
MORPHOLOGICAL SPECIES CONCEPT II Carl von Linne |
--type speciments = ideal example of what species should look like
-- species were considered fixed --variation was exception |
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*SPECIES*
TAXONOMY BIOLOGICAL SPECIES CONCEPT I |
Based on the ability to interpreed and produce viable fertile offspring
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*SPECIES*
TAXONOMY BIOLOGICAL SPECIES CONCEPT II Charles Darwin and other naturalists Charles Darwin |
--variation is common
--distinction between species is not always clear --species change over time --sometimes behavior is used to help classify species |
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*SPECIES*
TAXONOMY PROOBLEMS WITH THE SPECIES CONCEPT |
--gradual variation over a geogrpahical range (ex. salamanders (cline)
--when the range of 2 species begins to overlap , if they interbreed, they were one allopatric (geograph.) species rathere than different species |
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TAXONOMY
SYMPATRIC SPECIES |
species occupying the same area at the same time
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TAXONOMY
ALLOPATRIC SPECIES |
species separated by time and Place (can occupy the same area)
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*SPECIES*
Founder Effect |
Founder Effect occurs when one or a few individuals for a new population. When this happens, only a subset of the possible genetic material present in the larger population can possibly be present in the new, small one. The founder effect is a type of genetic drift because gene frequencies changed by chance alone, and not for an adaptive reason.
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*SPECIES*
NATURAL SELECTION Explain survival of the fittest |
Individuals who survive are the ones who are best suited to the environment due to variations
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*SPECIES*
MUTATION |
randon change in DNS
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*SPECIES*
ANALOGOUS STRUCTURE |
structures that have different origins but the smae functions due to the same selective pressures
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*SPECIES*
HYBRID |
Organisms that do not breed in nature but do breed or produce fertile offspring in artificial settins
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*SPECIES*
PHENOTYPE |
The physical characteristics produced by DNA
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*SPECIES*
SELECTIVE PRESSURES |
Factors that detemine which indivuduals will survive and reproduce
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*SPECIES*
HOMOLOGOUS STRUCTURE |
Structures that have a similar origin but diff function (forelimbs of vertebraes)
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*SPECIES*
WHy is the species Levels of organization conceptual |
Species is human construct that helps to classify things
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*SPECIES*
CONTINENTAL DRIFT Evidence of the the fact that earth crust and mantle moving |
maps, fossils, hot spotsm geologic movement (countries fit together)
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*SPECIES*
CONVERGENT AND DIVERGENT evolution are not opposites |
because in convergent the DNA is different to begin with (species will never become one)
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*SPECIES*
Problem with classifying species - example |
gradual variation over geographica range within California salamanders
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