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BSCI 1511 > Species and Speciation > Flashcards

Species and Speciation Flashcards

1
Q

define speciation

A

origin of new species is at key point where microevol intersects macroevol

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2
Q

What causes the formation of new species

A

repro isolation

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3
Q

define species

A

repro compatible and cannot interbreed wit other pops

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4
Q

what allows repro compatability

A

gene flow

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5
Q

what causes repro incompatability

A

dec gene flow btwn pops so pops can diverge in allele freq by drift or NS or both and become repro isolated

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6
Q

define repro isolation

A

bio factors/barriers that keep 2 species from producing viable and fertile offspring

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7
Q

what is the bio species concept

A

groups of actually or potentially interbreeding pops which are repro isolated from other such groups and produces viable, fertile offspring…absence of gene flow between pops

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8
Q

mechanisms of isolation

A

temporal/habitual, ethological/behavioral/sexual selection, mechanical, incompatability, hybrid inviability, hybrid sterility, hybrid breakdown

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9
Q

which mechs of isolation are prezygotic

A

temporal/habitual, ethological/behavioral/sexual selection, mechanical, incompatibility

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10
Q

which mechs of isolation are post-zygotic

A

hybrid inviability, hybrid sterility, hybrid breakdown

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11
Q

which mechs of isolation are pre mating

A

temporal/habitual, ethological/behavioral/sexual selection

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12
Q

which mechs are post mating(mating is attempted)

A

mechanical, incompatibility, hybrid inviability, hybrid sterility, hybrid breakdown

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13
Q

habitat isolation

A

live in/on diff habitats
flies on apple vs flies on peach
potential mates, but do not meet

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14
Q

temporal isolation

A

mate in diff seasons/time of day

potential mates but do not meet

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15
Q

behavioral isolation

A

diff courtships shows…mates not chosen by females

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16
Q

mechanical isolation

A

mating attempted, but physically can’t do it. 2 snails having diff chirality..genital openings don’t match up

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17
Q

gametic isolation

A

incompatible egg and sperm molecularly

lock and key for species-species interaction

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18
Q

define prezygotic barriers

A

impede mating, or hinder fert, or prevent attempted mating

19
Q

define postzygotic barriers

A

after a zygote is formed and fert is successful

20
Q

reduced hybrid viability

A

fert occurs but hybrid offspring is weak, sickly, can’t rlly survive well

21
Q

reduced hybrid fertility

A

vigorous but sterile

mules–> able to survivie fine but can’t mate with other mules

22
Q

hybrid breakdown

A

F1 hybrid are fine, but a backcross w/ organisms of 1 or other parental species causes recess alleles to be homozygous so less fit and sterile in F2
only affects F2 and later

23
Q

limitations of bio species concept

A

doesnt apply to fossils or asexual organisms

24
Q

morphological species concept

A

body shape and structural features w/o taking into account repro isolation
used for fossils alot
subjective

25
Q

ecological species concept

A

ecological niches, ex. polar bears and grizzlies

26
Q

phylogenetic species concept

A

defines species as smallest group of indiv that share a common ancestor forming 1 branch of the tree of life
based on dna seq

27
Q

define sympatric speciation

A

subset of a pop forms a new species w/o geographic separation… still living in same region

28
Q

define allopatric speciation

A

more common

pop forms a new species while geographically isolated from its parent pop

29
Q

what are the 2 types of allopatric speciation

A

vicariance and dispersal patterns

30
Q

vicariance

A

barrier is being formed while speciation occurring

population preexists and occupied both areas before but smth like a road or river intervenes and separates the two areas

31
Q

dispersal

A

2 diff islands, 1 large pop on one island, some migrate to other island and distance acts as barrier if no more migration

32
Q

how is speciation maintained in sympatric pops

A

habitat diff
polyploidy
sexual selection

33
Q

habitat diff

A

apple maggot flies on domestic apples and on smaller native fruits…flies emerge and return to fruit they were born in

34
Q

autopolyploidy

A

both chromosomes from same species
if all indiv in original pop are diploid, if cell div error occurs now tetraploid
tetraploid produces diploid gametes and if gametes mate then form a new species that is 4n
tetraploid isolated from diploid

35
Q

allopolyploidy

A

chromosome sets are derived from diff species
fertile w/ each other but sterile to other species
exhibit characteristics of both parents…a blend
new species has diploid chromosome number equal to the sum of diploid chromosome number from each parent
diploid 2n=6 + diploid 2n = 4 –> offspring 2n = 10 that is viable and fertile

36
Q

sexual selection

A

fish with red and blue backs

37
Q

define hybrid zones

A

regions where diff species w/ incomplete repro barriers mate and produce hybrids
yellow and fire bellied toads
enables us to study the process of speciation and mech of repro isolation
repro barriers are incomplete

38
Q

when hybrids don’t become repro isolated from parent species….what are the 3 possible outcomes

A
  1. reinforcement
  2. fusion
  3. stability
39
Q

reinforcement

A

NS favors indiv of 1 species to mate w/ indiv of same species….eventually limit hybrid zone
keeps 2 distinct species

40
Q

fusion

A

speciation starts but stops

collapse of repro barrier

41
Q

stability

A

formation of stable hybrid zone occurring cont

42
Q

key points on speciation

A

bio species concept emaphsizes repro isolation
speciation can take place w/ (allopatric) or w/o (sympatric) geographic separation
hybrid zones reveal factors that cause repro isolation and insight in speciation process
speciation can occur rapidly or slowly
speciation can occur through mutation (polyploidy), drift (geo iso), and/or selection
speciation can result from changes in few or many genes

43
Q

all organisms are related to each other via tree of life

A

trueeeee

44
Q

what does tempo of speciation depend on

A

lineage and env

BSCI 1511 (23 decks)

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