Mammals

Question 1

Mammal soft tissue characteristics

Answer 1

• lactation
• fur and hair
• diaphragm
• only left aortic arch
• red blood cells lack nucleus

Question 2

Mammal hard tissue characteristics

Answer 2

• only one lower jaw bone, dentary
• 3 small ear bones
• differentiated teeth and 1 time tooth replacement

Question 3

Milk and lactation

Answer 3

Mammal characteristic
- contains fats which can vary between species
- costly to produce milk
- carnivores usually have richer milk due to more fat and protein consumption

Question 4

Milk comparison between Rhino and Seal

Answer 4

fat %: Rhino = 0.2%, Seal = 60%
Seal needs to develop faster so need higher energy milk
- Rhino has long lactation period

Question 5

Mammalian hair

Answer 5

Keratin
- produce sebum to make hair waterproof
- arrector pili muscle
- raised hair to insulate, trapping warm air

Question 6

Pillage

Answer 6

patch of skin with shorter hair that can be exposed to cool down skin or protected to save heat

Question 7

Diaphragm

Answer 7

intercostal muscles contracting and relaxing for lung movement and oxygen intake
creates negative pressure

Question 8

Mammal circulatory system

Answer 8

only left aortic arch, complete separation of blood

Question 9

Red blood cells in mammals

Answer 9

very small, dont have nucleus or mitochondria
means cell can be full of haemoglobin for transporting oxygen

Question 10

3 inner ear bones

Answer 10

Malleus, incus, stapes

Question 11

hard tissue structure in mammals

Answer 11

only one main bone for lower jaw, other bones became part of the ear for sound reception

Question 12

Teeth mammals

Answer 12

Heterodonty
- one time tooth replacement
- different types of teeth for different functions
- molars, incisors, canines

Question 13

Monotremes

Answer 13

• lack nipples
• lay eggs
• milk is secreted from chest

Question 14

Marsupials

Answer 14

• embryo develops in marsupium/pouch
• born early in development, then latches onto a nipple in the pouch for rest of development

Question 15

Eutherians

Answer 15

• have amniotic egg
• yolk sac is important until the chorion connects with mothers blood supply, so embryo get oxygen and nutrients from mother
• large energy investment
• has a placenta

Question 16

Reproduction in mammals

Answer 16

• only produces a few offspring at a time
• females put in a large energy investment
• usually parental care

Question 17

2 strategies for parental investment

Answer 17

1. large amount of early development occurs in gestation (eutherians)
2. majority of early development in lactation (marsupials and monotremes)