Lecture 8 RH - Mammals Flashcards Preview

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Flashcards in Lecture 8 RH - Mammals Deck (75)
1

What organ is common to all mammals?

Mammary glands

2

What are the general characteristics of mammals?

Hair as body covering

Integument with sweat, scent, sebaceous, and mammary glands

Structure of skull and skeleton

Diphyodont teeth - milk or deciduous teeth replaced by permanent teeth

Heterodont teeth - Different types

Lower jaw is made up of single dentary bone

Secondary palate that separates nasal cavity from buccal cavity

Brain highly developed with large cerebral cortex

4 chambered heart

Left aorta

Non-nucleated biconcave red blood cells

Diaphragm divides body into thorax and abdomen

3

What is lower jaw made up of in mammals?

Single dentary bone

4

What is the function of the secondary palate?

Separates nasal cavity from buccal cavity

5

What does the brain of mammals look like?

Highly developed with large cerebral cortex

6

Do mammals have a cloaca?

Only monotremes. The rest of mammals have separate anal and urinary openings

7

Are mammals mono or dioecious?

Dioecious

8

What is the copulatory organ of mammals?

Penis

9

Is fertilization internal in all mammals?

Yes

10

What are the foetal membranes in mammals?

Amnion

Chorion

Allantois

11

What are the 3 major groups of amniotes?

Anapsid: Solid skull (turtles and ancestors)

Synapsid: Pair of openings in roof of skull for jaw muscle attachments (led to mammals)

Diapsid: 2 pairs of openings in skull roof (dinosaurs, reptiles, birds)

12

What are monotremes?

Mammals that lay eggs; eg platypus

13

Which mammals have only survived in Australia?

Marsupials and monotremes have only survived in Australia

14

What is hair composed of?

keratin

15

What other structures are composed of the same component as hair?

Nails, horns, claws, hooves, and feathers

16

Do mammals moult?

Periodically 2 coats - summer and winter coats

17

What is the purpose of moulting?

Camouflage

Sensory hairs

Spiny armour in porcupines, echidnas

18

What are true horns of sheep and cattle made of?

Sheaths of keratinized epidermis

19

What are antlers of deer made of?

Solid bone branched

20

How do antlers develop?

Beneath vascular velvet skin and they decline after rutting season as hormones decline

21

What is rhino horn made of?

Hairlike keratinized filaments and is used for chinese medicine driving it to near extinction

22

What is interesting about antelope horns?

They shed annually

23

What is rhino horn used for?

Chinese medicine

As an aphrodisiac

24

What are the types of sweat glands?

Eccrine glands produce sweat to cool skin

Apocrine glands open to hair follicle. Milky fluids - activity is correlated to reproductive cycle

25

What are scent glands used for?

Social activity such as marking territory

Mating scents to attract opposite sex

26

What is the function of sebaceous glands?

Produce sebum which keep skin pliable and glossy

27

Do monotremes have nipples?

No

28

What happens to metabolism in smaller animals compared to larger animals?

Metabolic rate/gram of body weight is a lot higher in smaller animals

29

What is the cost of migration?

Very energetically expensive

30

What is an example of a mammal that migrates?

Caribou migrate from Canada and Alaska and vice versa from Winter feeding grounds to summer breeding grounds in Canada

31

Where do seals migrate to and from?

Pribilof Islands in summer and Autumn.

Males arrive from the South where they live during Winter and Spring.

Females arrive from the Southeast near Alaska

32

How does echolocation in bats work?

Ultrasonic high frequency pulses. Echo is received by large ears

33

How are mammals classified into subclasses and infraclasses?

Reproduction

34

What are the types of reproduction in mammals?

Prototherians: Egg laying oviparous mammals

Metatherians: Pouched viviparous mammals

Eutherians: Placental viviparous mammals

35

How many orders does subclass prototheria have?

1; only the monotremes

36

How many orders does subclass theria have?

Infraclass metatheria has 7 orders of marsupials

Infraclass eutheria has 21 orders of placentals

37

How many species of monotremes are there?

5 species:

Duck-billed platypus

4 kinds of spiny anteater

38

What are the features of monotremes?

All lay eggs and suckle young

39

Where are individuals of infraclass metatheria located?

Most of the species are native to Australia and nearby Islands

Only opossums are found in North America

40

How do metatherians develop?

Young are born in an undeveloped state and complete development in a permanent pouch on mother

41

How long is the gestation period in Kangaroos?

33 days

42

How many young do kangaroos typically get at one time?

3

43

What happens to fertilized embryos when another joey is suckling within the pouch?

Embryos that are fertilized are in diapause

44

What is the placenta composed of?

Maternal and fetal tissues; nourishes foetus, delivers oxygen, removes wastes

45

Which develop quicker marsupials or placental mammals?

Placental mammals

46

What are the types of mating systems?

Promiscuous: Male makes little contribution: mate with any receptive female

Monogamous: Male mates with only one female at a time makes significant parental investment

Polygamous: Commonest in mammals. Group is dominated by one or several males that have exclusive mating privileges with all receptive females in group

Polyandry: Rare in mammals. Female has several male mates simultaneously

47

What are the orders of eutherians?

Rodentia (rodents)

Chiroptera (bats)

Soricomorpa (shrews and moles, insect eaters)

Primates

Carnivora

Artiodactyla (even-toed hoofed animals)

48

How are mammalian orders grouped?

Specialists don't agree on how to group the numerous eutherian orders

Cladogram based on analysis of 104 cranial characters developed in 1986

Jaws and cranial characters are related to the type of diet and development of brain

49

What is the superorder that contains insectivores?

Xenarthra

50

What are the orders of insectivorous mammals?

Pilosa: contains suborder folivora (sloths) andsuborder Vermilingua (anteaters)

Cingulata - armadillos

51

What are the features of xenarthra?

Many equipped with strong claws to tear open termite and ant nests

Long and sticky tongue

Order pholidota: contains pangolins or scaly anteaters of Africa and Southeastern Asia

52

What are pholidote scales made of?

Hairs that are cemented together

53

What are features of order tubulidentata?

Large claws, pointed snout, peg shaped cheek teeth.

Enamel has been lost but teeth do not wear out because they grow continuously

54

What is an example of a tubulidentata?

Aardvark

55

What order are hedgehogs, shrews, and moles a part of?

Soricomorpha

56

What ancestral features are retained by insectivorous mammals?

Relatively small brain

Limb structure is primitive

Five clawed toes

Dental formula primitive

57

What is the dental formula of insectivores?

I 3/3 C1/1 Pm 4/4 M 3/3

58

What are the adaptations of teeth in carnivorous mammals?

Large canines

Cusps on last upper premolar and first lower molar enlarged and moved into the same plane to form a set of carnassial teeth well adapted for slicing through meat

59

Why do carnivore jaws lock onto each other?

Jaws are hinged to close like a pair of scissors

60

What do sea lions, seals and walruses feed on?

Sea lions, seals and walruses live in the ocean and feed on fish or molluscs.

61

What are adaptive features of carnivores?

Terrestrial forms have developed claws, and a limb structure for rapid running to catch prey.

Foot posture is evolved into a digitigrade type -stand on toes with the rest of the goot raised off the ground like a sprinter

62

Where do sea lions, seals, and walruses breed?

They return to land for breeding

63

What have limbs of sea lions, walruses, and seals evolved into?

Flippers

64

What are the adaptations of aquatic mammals to life in the water?

Fish shaped body

Hind limbs embedded in body wall

Pectoral flippers for steering and balancing

Powerful tail fluke or fin used to propel animal

65

What are some examples of toothed whales?

Killer whales

Dolphins

Porpoises

Sperm whales

66

What do toothed whales feed on?

Fish and other large marine animals

67

How do toothed whales navigate?

High frequency echolocation

68

What are some examples of baleen whales?

Humpback whale

Blue whale

Rodwan Halimi

69

What is the function of songs of whales?

Finding a mate

70

What is the method of feeding of balleen whales?

horny plates hang down from palate and strains small invertebrates and other plankton as food

71

What are the adaptations that herbivorous mammals have?

Change in dentition to grind plant matter

In some groups ofherbivorous mammals the premolars assume the form of molars to make an effective battery of crushing and grinding teeth

Jaw is hinged to bring teeth together at the same time

Fore and aft and sideways movement of jaws is possible

72

What do bunodont molars look like in primitive herbivores and omnivores?

Square or rectangular crown, four primary rounded cusps on each molar

73

What do bunodont molars look like in more advanced herbivores?

High crowned teeth

Teeth resistant to wear

74

What do lophodont molars look like?

Pattern of ridges and crests

75

What do selenodont molars look like?

pattern of crescents