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AP Biology > Unit 1:part 2 (lesson 5+) > Flashcards

Unit 1:part 2 (lesson 5+) Flashcards

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1
Q

speciation

A

the process by which one species splits into two or more species

  • responsible for the diversity of life
  • explains differences and similarities between species
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2
Q

microevolution

A

changes over time in allele frequencies in a population

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3
Q

macroevolution

A

broad pattern of evolution above the species level

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4
Q

biological species concept

A

says that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring-but do not produce such offspring with other species

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5
Q

reproductive isolation

A

the existence of biological factors that impede members of two species from interbreeding and producing viable, fertile offspring

  • block gene flow between species
  • limit hybrids
  • types: prezygotic and postzygotic
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6
Q

hybrids

A

offspring that results from the mating of two individuals from different species

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7
Q

prezygotic barriers

A

block fertilization from occurring

types: habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, gametic isolation

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8
Q

postzygotic barriers

A

prevent a hybrid zygote from developing into viable, fertile adult
types: reduced hybrid viability, reduced hybrid fertility, hybrid breakdown

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9
Q

habitat isolation

A
  • prezygotic barrier

- two species that occupy different habitats in the same area may encounter each other rarely

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10
Q

temporal isolation

A
  • prezygotic barrier

- species breed at different times of day, different seasons, or different years

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11
Q

behavioral isolation

A
  • prezygotic barrier

- courtship rituals that attract mates and other behaviors unique to a species may cause isolation

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12
Q

mechanical isolation

A
  • prezygotic barrier

- mating is attempted but morphological differences prevent its successful completion

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13
Q

gametic isolation

A
  • prezygotic barrier

- sperm of one species may not be able to fertilize the eggs of another species

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14
Q

reduced hybrid viability

A
  • postzygotic barrier
  • genes of different parent species may interact in ways that impair the hybrid’s development or survival in its environment.
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15
Q

reduced hybrid fertility

A
  • postzygotic barrier

- hybrids are sterile

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16
Q

hybrid breakdown

A

-postzygotic barrier

some first generation hybrids are viable and fertile but their offspring are feeble and sterile.

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17
Q

limitations of the biological species concept

A
  • can be applied only to a limited number of species
    - does not apply to organisms that reproduce asexually
  • cannot evaluate fossils
  • some species are morphologically and ecologically distinct but have gene flow
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18
Q

morphological species concept

A

characterizes a species by body shape and structural features
-distinguishes most species but can be subjective

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19
Q

ecological species concept

A

views species in terms of its ecological niche; the sum of how members interact with nonliving and living parts of their environment

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20
Q

phylogenetic species concept

A

defines a species as the smallest groups of individuals that share a common ancestor, forming one branch of the tree of life
-compares separate species

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21
Q

allopatric (other country) speciation

A

gene flow is interrupted when a population is divided into geographically isolated sub- populations
-once separation has occurred, different mutations arise and natural selection and genetic drift may alter allele frequencies

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22
Q

Evidence for allopatric speciation

A
  • regions that are isolated or heavily subdivided typically have more species
  • reproductive isolation between two populations generally increases as the distance between them increases
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23
Q

Sympatric (Same Country) Speciation

A
  • speciation that occurs in populations that live in the same geographic area
  • can result from polyploidy, habitat differentiation, or sexual selection
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24
Q

polyploidy

A

an accident during cell division that results in an extra set of chromosomes;
may allow a new species to originate
-most common in plants
-can result from non-disjunction

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25
Q

autopolyploid

A

an individual that has more than two chromosomes sets that are all derived from a single species

26
Q

allopolyploid

A

has 2 or more chromosome sets as a result of 2 different species interbreeding
-can mate with each other but not parent species

27
Q

habitat differentiation

A

genetic factors enable a sub-population to exploit a habitat or resource not used by the parent population

28
Q

non-disjunction

A

when homologous chromosomes do not separate during meiosis, sex cell will contain too few or too many chromosomes

29
Q

hybrid zone

A

a region in which members of different species meet and mate, producing at least some offspring of mixed ancestry
-form when 2 species lacking complete barriers to reproduction come into contact

30
Q

reinforcement

A

strengthening of reproductive barriers

-can occur when hybrids are less fit than parent species

31
Q

fusion

A

weakening reproductive barriers
-much gene flow occurs between two species, gene pools become increasingly alike and eventually fuse into a single species

32
Q

Stability

A

continued formation of hybrid individuals

  • sometimes hybrids are fitter
  • sometimes hybrids are at disadvantage but a small hybrid zone with migration might occur
33
Q

punctuated equilibria

A

In the fossil record, long periods of apparent stasis in which species undergo little or no morphological change interrupted by relatively brief periods of rapid speciation

34
Q

Speciation Rates

A
  • experiments and observations suggests that once the process of speciation begins, it can be completed rapidly
  • on average, millions of years may pass before a newly formed species will give rise to another species
35
Q

plate tectonics

A

continents are part of great plates on Earth’s crusts that essentially float on the mantle
-plates move over time

36
Q

Consequences of Continental Drift

A
  • alters habitats in which organisms live
  • causes climate changes as continents shift location: organisms adapt, move, or become extinct
  • promotes allopatric speciation (continents break apart)
  • helps explain geographic distribution of extinct organisms.
37
Q

Pangaea

A

supercontinent formed about 250 million years ago

  • destroyed shallow water habitats, interior cold and dry
  • caused extinction, new opportunities for surviving species
38
Q

Mass Extinction

A

time in which large numbers of species became extinct

39
Q

Permian Mass Extinction

A
  • between paleozoic and mesozoic eras
  • claimed 96% of marine species and many insect species
  • enormous volcanic eruptions in Serbia 251 million years ago
  • warmed atmosphere, oxygen levels dropped
40
Q

Cretaceous mass extinction

A
  • between Mesozoic and Cenozoic eras
  • about 65.5. million years ago
  • 50% of marine species and many terrestrial plants and animals extinguished
  • hypothesized to have been caused by an asteroid striking the earth
41
Q

Consequences of Mass Extinctions-

A
  • reduces diversity of life
  • changes types of organisms found in ecological communities
  • can end lineages with highly advantageous features
  • paves way for adaptive radiations
42
Q

Adaptive Radiations

A

periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities

  • often occur after mass extinctions
  • organisms increase in diversity as they play new roles in the environment
  • organisms that arise can serve as new food source
43
Q

taxonomy

A

the scientific discipline of naming and classifying organisms

44
Q

binomial nomenclature

A

names organisms using two part name

-genus name+ specific epithet

45
Q

Hierarchical Classification

A 
Domain
Kingdom
Phyla
Class 
Order
Family
Genus 
Species
46
Q

phylogenetic tree

A

a branching diagram that represents a hypothesis about the evolutionary history of a group of organisms

  1. Intended to show pattern of descent, not phenotypic similarity
  2. Sequence of branching in a tree does not necessarily indicate the actual age of a species
  3. Do not assume that a taxon evolved from a taxon next to it
47
Q

PhyloCode

A

a system of classification that only names groups that include a common ancestor and all of its descendents

48
Q

rooted

A

describes a phylogenetic tree that has a branch point that represents the most recent common ancestor of all taxa

49
Q

polytomy

A

a branch point from which more than 2 descendent groups emerge
-signifies evolutionary relationships among taxa not yet clear

50
Q

homoplasies

A

analogous structures that arose independently

51
Q

molecular systematics

A

the discipline that uses data from DNA and other molecules to determine evolutionary relationships

52
Q

cladistics

A

an approach to systematics that uses common ancestry as the primary criterion to classify organisms

53
Q

clades

A

groups that include an ancestral species and all of its descendents

54
Q

monophyletic

A

a group that consists of an ancestral species and all of its descendants

55
Q

paraphyletic

A

consists of ancestral species and some of its descendents

56
Q

polyphyletic

A

includes new taxa with different ancestors

57
Q

shared ancestral characters

A

a character that originated in an ancestor of the taxon

58
Q

shared derived characters

A

an evolutionary novelty unique to a clade

59
Q

outgroup

A

a species or group of species from an evolutionary lineage that is known to have diverged before the lineage that includes the group we are studying

60
Q

maximum parsimony

A

the principle that systematists should first investigate the simplest explanation that is consistent with all of the facts
- requires fewest evolutionary events, or fewest DNA base changes

61
Q

maximum likelihood

A

given certain probability rules about how DNA sequences change over time, a tree can be found that reflects the most likely sequence of evolutionary events

AP Biology (17 decks)

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