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Diversity of life B > Week 7 - Evolution and diversity of mammals 1 > Flashcards

Week 7 - Evolution and diversity of mammals 1 Flashcards

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1
Q

What is the difference between adaptive and convergent evolution ?

A

Convergent evolution = animals come to resemble each other but aren’t closely related
Adaptive evolution = Change in the genetic makeup of a population over generations that increases its fitness in a given environment

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2
Q

What 2 subclasses is the class mammalia split into ?

A

Prototheria and theria

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3
Q

Which of the mammalia subclasses lays eggs and which gives birth to live young?

A

Prototheria = egg layers
Theria = live young

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4
Q

What are the 3 main mammal orders ?

A
  1. Monotremata (prototheria)
  2. Marsupialia (Metatheria)
  3. Placentalia (Eutheria)
    (Therians divided into 2 & 3 )
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5
Q

What is the difference between mammae and mammillae ?

A

Mammae are the modified sweat glands that produce the milk
Mammillae is the nipple/teat that delivers the milk

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6
Q

What is one of the most key defining features of mammals?

A

The articulation of the dentary and squamosal bones in our skulls - the dentary bone (lower jaw) now meets the squamosal bones.

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7
Q

How did the middle ear structure form in mammals and why was this beneficial?

A

Two of these other bones, the quadrate and articular shifted backwards, upwards and inwards and now form part of the working of our middle ears.
Having these bones in the middle ear created an ear structure that not only transmits sound waves but amplifies them and therefore allowed for more acute hearing.

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8
Q

What is another characteristic of mammals related to teeth?

A

Teeth are only replaced once, or never

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9
Q

What is the benefit of having 2 occipital condyles rather than 1 ?

A

2 occipital condyles where skull meets topmost neck vertebra.
- reduced tension on the spinal cord when the head is moved vertically and also allowed for finer control of head movements although reduced lateral movement.

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10
Q

What are the 3 main groups of amniotes ?

A

Anapsids
Diapsids
Synapsids

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10
Q

How can you identify the different amniote groups ?

A

They are distinguished by the number of lateral temporal fenestrae (openings) in their skull

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11
Q

How many openings did each group of amniotes have in their skull?

A

Anapsid = None
Synapsid = 1 (on each side)
Diapsid = 2 (on each side )

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12
Q

What is the only surviving group anapsids ?

A

Chelonians (turtles)

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13
Q

What did the diapsids diversify into?

A

Reptilian clades

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14
Q

Which group of amniotes gave rise to the mammalian clade ?

A

Synapsids

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15
Q

Which order of synapsids first showed mammalian characteristics ?

A

Pelycosauria

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16
Q

Which more advanced synapsid order replaced the pelycosauria?

A

Therapsids

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17
Q

What mammal characteristics did therapsids have ?

A
  • Limbs beneath body (confers more rapid locomotion)
  • Secondary palate separating mouth from nasal passages (eat and breathe at same time)
  • Still had bones in lower jaw that became incorporated into malleus and incus of middle ear in mammals.
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18
Q

Which were the first mammals ?

A

Triconodonta

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19
Q

What key characteristic did Triconodonta have?

A

Had cheek teeth with 3 conical cusps in a linear series

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20
Q

What is the only surviving order of prototherians ?

A

Monotremata

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21
Q

What are some characteristics of the order monotremata ?

A

Lay and brood eggs
Infants cant suck milk- lap it instead
Extant species lack teeth and are venomous

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22
Q

What are the 2 families prototherians are split into?

A

Enchidnas and Duck-billed platypus

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23
Q

What are some characteristics of Enchidnas ?

A

Have spines (not teeth)
Eat invertebrates
Eggs hatch after 10 days, gestation 2 weeks (short).
Young then move to a pouch, where they feed on milk for 6 months

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24
What are some characteristics of the Duck-billed platypus ?
Webbed feet Hunt for benthic invertebrates by echolocation 2 eggs / burrow, incubation 10 days, no pouch, 3-4 month lactation. Males have spurs on rear ankles connected to venom glands in thighs.
25
Which extinct taxa to therians evolve from ?
Trituberculata
26
What is the tribosphenic cheek tooth pattern and what is efficient about it ?
3 principal cusps in a triangle, middle one is dominant Efficient at shearing and grinding of food and allowed for efficient munching of insects.
27
Where abouts are the subclass marsupials found in the world today and where did they originate?
Australia now China and North America (originally)
28
Recount the adaptive radiation of marsupials across the globe ?
- Gondwana connected South America → Antarctica → Australia so marsupials moved to Australia - Australia separated from Antarctica - Marsupials isolated in Australia, massive speciation occurred Many marsupial went extinct when coexisting with placental mammals (eutherians).
29
Give an example of convergent evolution between marsupials and eutherians (placental)
Convergent evolution has meant some marsupials resemble placental mammals in similar ecological roles all across the world. E.g. Sugar gliders seem very similar to flying squirrel
30
What is the difference between reproductive strategies in marsupials vs eutherians (placental) ?
Eutherians: intricate placental relationship between foetal membranes and uterine linings. Marsupials also have a placenta, but only makes loose contact with foetus and it is short-lived.
31
What does a new born marsupial look like ?
Poorly developed but have well developed fore limbs so they can craw to nipple in pouch
32
What are the 4 main super-orders of the Placental mammals (eutherians )?
Afrotheria Xenarthra Laurasiatheria Euarchontoglires
33
How many orders does the super order Afrotheria contain and name some?
6 Tenrecs and golden moles Sengis Aadvark Elephants
34
What type of evolution occurs between afrotheria and other superorders ?
Convergent
35
What are the 2 living species of elephants?
African and Indian
36
What is the function of large elephant ears ?
To dissipate heat
37
What kind of teeth are the elephant tusks ?
Elongated upper incisors
38
How is the elephant social system organised ?
Oldest female leads the group Males are alone Related females live together with offspring
39
How do elephants communicate ?
Communicate over long distances by infrasound - Extremely low-pitched rumbles to communicate over long distances. Infrasound is below the human hearing threshold <20H
40
Which infra order are golden moles convergent with ?
Eulipotyphlya moles
41
What are some features moles have for a burrowing lifestyle ?
Leathery pads on head and strong limbs
42
Which 2 orders is the super order Xenarthra split into?
Pilosa = anteaters and sloths Cingulata = Armadillos
43
What are some features of Xenarthra ?
Teeth reduced or lost Large claws on toes Diet is low in energy content
44
What 2 families are sloths split into ?
2-toed or 3-toed
45
What characteristics to armadillos have?
Tough carapace develops from skin and is composed of strong, bony plates- overlaid by horn
45
What type of lifestyle do sloths have ?
Arboreal - leaf eating lifestyle with few competitors
46
47
What is the first small mammal order called ?
Eulipotyphla
48
What are some features of Eulipotyphla ?
- primitive - small smooth brain - many teeth - intra-abdominal testes (no scrotum) - have a cloaca
49
What is a cloaca ?
A common chamber where everything empties
50
What are some negatives of a small size?
High SA:V ratio so loose heat fast High respiratory rates Have to eat own body weight in insects everyday
51
What are the 4 families of the order Eulipotyphla ?
1. Shrews 2. Solenodons (not widespread) 3. Hedgehogs and moonrats 4. Moles and desmans
52
What are some shrew characteristics ?
- Smallest terrestrial mammal - Some emit ultrasonic clicks - form of echolocation. - Many are insectivorous
53
What are some Solenodos characteristics ?
Use crude echolocation Have toxic saliva to immobile prey Cartilaginous snout, articulates with the skull via a ball and socket joint in Hispaniola solenodon.
54
What are some mole and desman characteristics ?
Have poor vision but are very sensitive to touch, have richly endowed tactile organs
55
Of the Lagomorph order what species are included?
Rabbits, hares and pikas 92 species
56
What behaviour is copronphagy ?
Reingestion of faecal matter
57
What distinguishes lagomorphs from rodents?
Lagomorphs have peg teeth, a second pair of incisors behind upper pair
57
What is postpartum estrus? What animals does it occur in ?
Means that a female becomes fertile and can mate again very soon after giving birth Kangaroos and Lagomorphs
58
What is a prolific breeder?
An animal that produces lots of offspring over its life time
59
What are the 3 groups of the order Rodenta ?
- Squirrel-like - Mouse-like - Cavy-like
60
What are some examples of squirrel-like rodents? What are their teeth like?
Beavers Squirrels Teeth - simple and lack enamel
61
What are some examples of Mouse-like rodents?
Rats and mice; voles and lemmings; hamsters; gerbils
62
Are Mouse-like rodents a K or R strategist ?
R - adapted for early and prolific reproduction
63
What are some examples of Cavy-like rodents?
Cavies, cappybara, agoutis, chinchillas, porcupines, guinea-pigs and African mole rats. VERY DIVERSE
64
Describe reproduction in naked mole rat colonies
- In each colony a single pair breeds - Remaining colony members form casts Small workers: gather food and nest materials. Larger non-workers: stay near the queen, help defend the colony.
65
Are non-breeders sterile?
No they can form new colonies, and replace breeding animals if they die
65
What orders are the Ungulates (hoofed mammals) split into?
1. Odd toed (Perissodactyla) 2. Even toed (Cetartiodactyla)
66
What is meant by an odd toed ungulate ?
Axis of foot passes through 3rd largest toe
67
What is meant by an even toed ungulate ?
Axis of foot passes through 3rd and 4th toes
68
What are some examples of Perissodactyl ?
Horses, zebras, Tapirs and rhinos
69
How do perissodactyls communicate ?
Vocally
70
What are some examples of Artiodactyls?
Pigs, hippos, camels, llamas, ruminants
71
Which kind of ungulate is more diverse?
Artiodactyla
72
What is special about a ruminants stomach?
Have a fermentation chamber within multi-chambered stomachs to aid with cellulose digestion.
73
Deer have antlers what do bovids have?
Horns (e.g. cows, goats)
74
What adaptations does the order Carnivora have?
Skull adapted for killing and crushing prey Large canines Carnivorous but also veggies, insectivores and omnivores
75
What are some families of carnivores?
Hyaenas Ursidae (pandas) Felidae
76
What is a pseudopenis, and what do hyaenas use it for?
An enlarged clitoris resembling a penis in female hyaenas, females mate and give birth through it
77
What is the core of a lion pride?
4-12 related females
78
How to silverbacked jackal juveniles help their parents?
Juveniles stay in parental ranges as helpers: delay own reproduction by a year and help raise younger brothers and sisters.
79

Diversity of life B (10 decks)

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