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Flashcards in Exam 1 Deck (61)
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1

Three types of Biodiversity

Ecosystem, species, and genetic diversity

2

Speciation

the process by which one spp splits into two or more

3

Biological species concept: species def

a group of populations whose members have the potential to interbreed in nature and produce fertile offspring.

4

Reproductive isolation

prevents members of different spp from mating with each other; prevents gene flow between spp: therefore the spp are distinct from each other

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Conservation Biology

mission-oriented, crisis-driven, problem-solving field focused on the preservation of biological diversity

6

Extirpation

the loss of a single population of a species

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Extinction

irreversible loss of all populations of a species

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Hybrids

When some pairs of clearly distinct species occasionally interbreed and produce hybrids (ex: Grizzly and Polar Bear)

9

Morphological Species Concept

classifies organisms based on observable physical traits (applied to asexual organisms and fossils)

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Homology

the similarity in characteristics that result from common ancestry

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Homologous structures

have different functions but are structurally similar because of common ancestry

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Vestigial structures

remnants of features that served important functions in an organism's ancestors

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Nonhomologous/analagous traits

Similarities resulting from convergent evolution (similar habitats, diets, etc)

14

Ecological Species Concept

defines a spp by its ecological role or niche and focuses on unique adaptations to those roles in a biological community (ex: 2 spp may look similar but differ in diet or habitat)

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Phylogenetic Species Concept

(most modernly used) defines a spp as the smallest group of individuals that shares a common ancestor (done by testing DNA or morphology)
-difficulty in determining amt difference necessary to separate spp

16

3 Key Points about Evolution by natural selection

1) Individuals do not evolve: populations evolve
2) natural selection can amplify or diminish only heritable traits, not acquired ones
3) evolution is not goal directed and does not lead to perfection (favorable traits vary as envr changes)

17

3 Modes of natural selection

-directional (causes characteristics to take one extreme more)

-stabilizing (keeps characteristics more moderate-extremes die)

-disruptive (some factor causes all moderates to die, almost creating two spp of remaining extremes, but factor leaves and spp come back together)

18

Mutation definition

changes in the nucleotide sequence of DNA and the ultimate source of new alleles

19

Prezygotic Barriers

(physical barriers before zygote formation) Habitat (Garter snakes), temporal (E&W Spotted Skunks), behavioral (birds), mechanical (flies), and gametic isolation (corals&anemones)

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Postzygotic Barriers

(genetic/embryonic barriers after zygote formation) Reduced hybrid viability, reduced hybrid fertility, hybrid breakdown

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Allopatric Speciation

when landmasses separate organisms and prevent them from mating (ex: Antelope Squirrels)

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Polyploidy

cells have more than two complete sets of chromosomes

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Sympatric Speciation

can result from polyploidy by self-fertilization or by hybridization (80% of all living plant spp)

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Adaptive radiation

the evolution of many diverse spp from a common ancestor (ex: the Galapagos Archipelago-finches)

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Supporting services (MA: eco services)

nutrient cycles and pollination

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Provisioning Services (MA: eco services)

providing food and clean water

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Regulating Services (MA: eco services)

control of climate, pests and disease

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Cultural Services (MA: eco services)

spiritual and recreational benefits

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Millennium Ecosystem Assessment

(MA) produced by the federal govt in 2001. Popularized the term "ecosystem services"

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Mobile Links

spp that provide critical ecosystem services and increase resilience by connecting habitats and ecosystems as they move between them