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53 Cards in this Set
- Front
- Back
macroevolution |
the evolutionary change that produce new species and new groups of species; occurring over long periods of time |
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species |
group of organisms that maintains a distinctive set of attributes in nature
there's much difficulty in differentiation and identification because of subspecies and ecotypes |
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ecotypes |
genetically distinct population of a species adapted to its local environment |
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subspecies |
two or more geographically restricted groups of the same species display one or more traits that are different but it isn't enough to be completely different species |
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speciation |
the mechanisms that promote the formation of new species |
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morphological identification of a species |
looking at phenotypes
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problems of using morphological identification of a species |
how to tell what level of dissimilarity will deem a new species
some species can look entirely different but are still the same and some look the same and aren't |
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reproductive isolation |
prevents one species from successfully interbreeding with another species |
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reproductive isolation identification of a species |
if they can't mate then they aren't the same species
must be viable and fertile offspring |
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problems of reproductive isolation identification of a species |
difficult to determine in nature
some species can interbreed and yet do not
doesn't apply to asexual species
can't be applied to extinct species |
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molecular identification of a species |
involves comparing of DNA sequences within genes, gene order along chromosomes, and its chromosome structure and number |
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problems with molecular identification of a species |
what degree of dissimilarity should be the cutoff? |
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ecological identification of a species |
relates species to the similarity of lifestyles and habitats/conditions
used mostly for prokaryotes (bacteria) |
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problems of ecological identification of a species |
many species will have similar ecology |
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evolutionary identification of a species |
looking at evolutionary trees and see if they come from a common ancestor or not |
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species concept |
way of defining the concept of a species or distinguishing species from anothe |
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biological species concept |
defines a group of individuals whose members have the potential to interbreed with another to produce viable, fertile offspring |
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evolutionary lineage concept |
species should be defined based on the separate evolution of lineages |
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lineages |
a series of species that forms a line of descent |
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ecological species concept |
each species has an ecologic niche |
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general lineage concept |
each species is a population of an independently evolving lineage |
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reproductive isolating mechanisms |
prevent interbreeding between different populations; pre and post -zygotic |
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types of pre zygotic mechanisms |
habitat, temporal, behavioral, mechanical, and gametic isolation |
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types of post zygotic mechanisms |
reduce hybrid viability, hybrid sterility, and hybrid breakdown |
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habitat isolation |
species occupy different areas/habitats or have geographic barriers and therefore do not come in contact to mate |
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temporal isolation |
the species reproduce at different times |
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behavioral isolation |
courtship rituals and other behaviors are unique to species and act as a barrier |
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mechanical isolation |
morphological differences in genitalia prevent successful intercourse |
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gametic isolation |
fertilization unsuccessful due to gametic incompatibility
important to species that release gametes into water or air |
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post zygotic barriers |
are less common and are more costly in terms of energy and resources used |
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reduced hybrid viability |
fertilized gee doesn't develop past an early embryo |
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hybrid sterility |
hybrid survives into birth, but is sterile |
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hybrid breakdown |
hybrid viable and fertile, but subsequent generations develop genetic abnormalities |
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speciation |
accumulation of genetic changes that ultimately promote enough differences so that a population constitutes a whole new species
requires interruption of gene flow between populations |
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how speciation occurs |
1. due to abrupt events like changes in chromosome number
2. arise out of adaptation to ecological niche |
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cladogenesis |
splitting or diverging or a population into two or more species |
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allopatric speciation |
most prevalent way for cladogenesis to occur; involves the geographic isolation of populations
interrupts gene flow, eventually creating new species |
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hybrid zone |
where two populations can meet and interbreed because geographic separation is incomplete
once gene flow is greatly diminished, the two population can have enough reproductive isolation to lead to speciation |
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adaptive radiation |
single species evolves into an array of descendants
they may differ in habitat or behavior
can also be caused from drastic environmental change |
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sympatric speciation |
no physical barriers to interbreeding, yet speciation occurs
can be from adaptation to sub-habitat |
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causes of sympatric speciation |
adaptation to local environments, polyploidy, sexual selectin |
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polyploidy |
causes immediate reproductive isolation; where an organism has more than two sets of chromosomes and now gametes are no longer compatible
plants more tolerant than animals |
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allodiploid |
an organism that has one set of chromosomes from two different species |
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allotetraploid |
an organism have two sets of chromosomes from both parents, for a total of four sets |
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evolutionary developmental biology |
compares the development of different organisms to understand ancestral relationships and evolutionary mechanisms that bring about evolutionary change |
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development |
series of changes in the state of a call, tissue, organ, or organism |
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pattern formation |
a specific body pattern formed from four processes |
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four processes of pattern formation |
involves the genes that influence cell division, cell migration, cell differentiation, and cell death |
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apoptosis |
the death of a cell |
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changes to a developmental gene can lead to a rapid change of... |
the morphology of an organism will determine where and how things develop in the embryo and into adulthood |
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hox genes |
determine the development of body plans, the more hox genes, the more complicated the body plan |
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order of complication of hox genes |
sponges -> anemones -> flatworms -> insects -> chordates -> mammals |
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heterochrony |
evolutionary changes in the rate or timing of developmental events |