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Zoo 201 > Synapsida Lecture (Amniote cont.) > Flashcards

Synapsida Lecture (Amniote cont.) Flashcards

(54 cards)

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1
Q

synapsids have (temporal)

A

one pair temporal skull opening behind orbits

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2
Q

synapsids = first lineage to

A

diverge from ancestral amniotes (sister lineage to class w/ other amniotes “diapsids”)

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3
Q

synapsids include

A

mammals (only extant lineage)

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4
Q

Evolution of mammals lineages (3)

A

pelycosaurs, therapsids, cynodonts

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5
Q

Pelycosaurs are the

A

most basal synapsids

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6
Q

pelycosaurs radiation

A

into diverse lineages (carnivores & herbivores)

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7
Q

pelycosaurs extinct

A

by end of paleozoic

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8
Q

pelycosaurs monophyletic or paraphyletic?

A

paraphyletic (therapsid lineage emerged w/in a carnivorous pelycosaur lineage)

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9
Q

Therapsids radiation

A

into diverse lineages (carnivores & herbivores)

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10
Q

therapsids persisted

A

into mesozoic

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11
Q

therapsids monophyletic or paraphyletic?

A

paraphyletic (cynodont lineage emerged w/in therapsid lineage)

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12
Q

Cynodonts exhibited (2)

A
  • heterodonty = differentiation of tooth types

- changes in jaw musculoskeletal structure

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13
Q

cynodont jaw musculoskeletal structure changes:

A
  • enlargement of dentary & reduction of posterior bones of mandible
  • evolution of masseter muscle = allows lateral jaw movements
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14
Q

cynodonts monophyletic or paraphyletic?

A

paraphyletic (mammal lineage emerged w/in cynodont lineage)

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15
Q

Early mammals arose

A

> 200 mya (Triassic)

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16
Q

early mammals exhibited (2)

A
  • diphyodont deviation = teeth replaced 1x in life

- new jaw joint btwn squamosal & dentary = quadrate & articular incorporated (w/ stapes) into middle ear

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17
Q

early mammal jaw & joint evolution

A

w/ time –> decrease in quadrate & articular, increase in dentary

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18
Q

what forms the jaw joint?

A

quadrate, squamosal, & articular

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19
Q

early mammals had ____ & were likely _________

A

hair, endothermic

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20
Q

early mammals also had a

A

secondary palate = separates feeding & breathing pathways / permits suckling by young

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21
Q

mammal hair

A
  • unique to mammals
  • dead cells w/ keratin
  • epidermal structure
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22
Q

derivatives of mammal hair (2)

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A
  • vibrassae (mechanoreception)
  • spiny armor (porcupines, hedgehogs, & echidnas have all independently evolved spines derived from hair) (protection against predators)
23
Q

great morphological variation through dental evolution is due to

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A

feeding specializations

24
Q

mammals have greatest variety of

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A

glands among vertebrates

25
mammal glands (4)
- sweat glands (evaporative cooling) - scent glands (communications (attracting mates, territorial marking)) (defense (skunks)) - sebaceous glands (expel sebum - keep hair/skin pliable) - mammary glands (possessed by females (rudiment in males)) (milk secreted from glandular tissue to feed young) * humans --> adipose tissue around glandular tissue forms breasts (unique & plays role as sexual signal)
26
mammary glands are homologous to
sweat glands
27
Mammalia =
Monotremata + Metatheria + Eutheria
28
monotremata reproduction
oviparous (lay & incubate eggs)
29
metatheria reproduction
vivaporous w/ altricial young (born at early developmental stage) (babies w/ eyes that can't open yet)
30
metatheria aka
"marsupials"
31
monotremata animals
platypus, echidna, etc.
32
metatheria animals
kangaroos, koalas, wallabies, Tasmanian devils, etc.
33
metatheria evolved most
ecological types seen in placental mammals except powered flight & marine habitat
34
metatherian females have
vagina w/ 2 lateral canals & medial canal (3 passageways)
35
metatherian males have
forked penises that fit lateral vaginal canals
36
metatherian sperm travel
up lateral canals & young pass through medical vaginal canal (t.f. different channels for insemination & birth)
37
metatherian young are born, then
climb to teat in pouch, & have extended development while nursing
38
eutherian aka
"placentals"
39
eutherian reproduction
viviparous w/ young born relatively precocial (born later in development)
40
eitheria made up of
almost 1/2 as rodents & almost 1/4 as bats
41
eutherian females have (2)
- a single vaginal canal | - placenta
42
placenta =
- connections form btwn fertilized egg & uterine fissure | - gas & nutrient exchange (thru blood exchange)
43
compared to metatherians, eutherians apply more energy towards
in utero development & less towards lactation
44
Monkeys monophyletic or paraphyletic?
paraphyletic
45
Great Apes =
Orangutans + Gorillas + Chimpanzees + Humans
46
ancestral great ape clade appeared
~14 mya
47
trends in lineage leading to humans (3)
- enlargement of the cranium - more reliance on vision / reduced olfactory (smell) capacity - paedomorphic characteristics (look like early stage of development in comparison to great apes) (we look like baby chimps)
48
earliest known hominin fossil
Sahelanthropus (then Ardipithecus & Australopithecus)
49
Human evolution (4)
- H. habilis (2.3 - 1.4 mya) - tools - H. erectus (1.8 to 0.1 mya) - more complex tools, fire, wore furs - first Homo to leave Africa! got to SE Asia - H. sapiens (~200Kya) - modern humans - H. neanderthalensis ~30Kya - "replaced" by H. sapiens
50
Homo appeared
2.3 mya
51
Homo sapiens arise hypotheses (2)
1. ) multiregional origin model (controversial) | 2. ) recent African origin model (more accepted)
52
Multiregional Origin Model
- H. erectus migrated from Africa to Asia, Europe, etc. - Geographically separated populations gave rise to phenotypical different races of H. sapiens - Gene flow prevented races from becoming species
53
Recent African Origin Model
- H. sapiens arose in Africa - H. sapiens migrated from Africa to regions where H. erectus had preceded them & replaced the (also replaced H. neanderthalensis) - only after leaving Africa & occupying new regions did phenotype differences btwn races arise.
54
Homo floresiensis
"the hobbits" - lived on Flores as recently as 13Kya - evidence indicates closest relative to H. erectus - dwarfism & persistent survival of forms extinct elsewhere is common on islands

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