Biodiversity - Mammals Flashcards
1
Q
number of mammal species
A
4500
2
Q
features of a mammal
4
A
- endothermic
- hair
- mammary glands for milk
- 4 chmabered heart
3
Q
why do mammals have hair
A
to keep heat they produce by insulating body
4
Q
2 types of hair
A
- under hair - insulation
- guard hair - protection
5
Q
features of hair
4
A
- made of keratin
- grows out of follicle
- oil gland
- tiny muscle pulls hair up when cold
6
Q
examples of modified hair
4
A
- quills - defence
- scales - water loss
- whiskers - sensory
- horn - protection
7
Q
how do sounds reach brain
A
- sound enters auditory canal
- then middle ear
- waves pass through malleus, inus then stapes
- cochlea sends signal to brain
8
Q
4 types of mammalian teeth
A
- incisors
- canies
- premolars
- molars
9
Q
what do incisor teeth do
A
cut or shear food
10
Q
why did mammals not go extinct with dinosaurs
A
bc of hair and fat which insulated them during cooler temp
11
Q
age of oldest mammalian fossils
A
220 million years old
12
Q
4 types of placental mammals
MELAX
A
- euarchontoglires
- laurasiatheria
- afrotheria
- xenarthra
13
Q
what are monotremes?
A
mammals that lay eggs
14
Q
monotreme features
A
- reptile and mammal characteristics
- lay eggs
- have cloaca
- hair
- mammary glands (no nipples)
15
Q
2 examples of montremes
A
- platypus
- echidna
