Chapter 4 Mammals-Section 3

Question 1

What characteristics do mammals share?

Answer 1

1) They are endothermic vertebrates
2) They have a four chambered heart
3) They have skin covered with fur or hair
4) They are born alive
5) Every young mammal is fed with milk produced by organs in its mother’s body

Question 2

What are the organs that produce milk in a female mammal’s body called?

Answer 2

Mammary glands

Question 3

What is the adaptation that most mammals have for obtaining food?

Answer 3

Teeth

Question 4

How many different shaped teeth do most mammals have?

Answer 4

Four

Question 5

Which type of teeth are flat edged teeth used to bite off and cut food?

Answer 5

Incisors

Question 6

What teeth are pointed teeth that stab food and tear into it?

Answer 6

Canines

Question 7

Which kind of teeth have broad, flat upper surfaces for grinding and shredding food?

Answer 7

Premolars and molars

Question 8

How many different species of mammals exist today?

Answer 8

4,000

Question 9

What large muscle is located at the bottom of the ribs and helps a mammal to breathe in and out?

Answer 9

Diaphragm

Question 10

What systems within the mammal help take oxygen to the cells?

Answer 10

The four chambered heart and a two-loop circulatory system

Question 11

What adaptations allow mammals to live in cold climates?

Answer 11

For and a layer of fat beneath their skin

Question 12

What are two ways mammals can move?

Answer 12

Kangaroos hop, and orangutans swing by their arms from branch to branch

Question 13

What are two things a mammal’s nervous system does?

Answer 13

1) coordinates it’s movements

2) receives information about the environment

Question 14

Give an example of how a mammals senses are highly developed and adapted for the way a species lives?

Answer 14

Dogs, cats, and bears often use smell to track their prey.

Question 15

What are the three main groups of mammals?

Answer 15

Monotremes, marsupials, and placental mammals

Question 16

What are egg laying mammals called? How many species are there and what are they?

Answer 16

Monotremes. There are just three species of monotremes…2 species of spiny anteaters and the duck billed platypus

Question 17

What are mammals whose young are born at an early stage of development, and they usually continue to develop in a pouch on their mother’s body? Give 3 examples

Answer 17

Marsupials. Koalas, kangaroos, and opossums

Question 18

What is the length of time between fertilization and birth called?

Answer 18

Gestation period

Question 19

Is the gestation period for marsupial short or long?

Answer 19

Short

Question 20

What do marsupial babies do when they’re first born?

Answer 20

They crawl along the wet fur of their mother’s belly until they reach her pouch. Once inside, they find one of her nipples and attached to it.

Question 21

How long do marsupial babies stay in their mothers pouch?

Answer 21

They remain in the pouch until they have grown enough to peer out of the pouch opening.

Question 22

How does a placental mammal develop?

Answer 22

A placental mammal develops inside it’s mother’s body until it’s body systems can function independently

Question 23

What is an organ in a pregnant female mammal, that passes materials between the mother and the developing embryo?

Answer 23

A placenta

Question 24

What does the mother pass to her young through the placenta? And what does the young pass to the mother to the placenta?

Answer 24

Food and oxygen passes from the mother to her young. Wastes pass from the young to the mother, who eliminates them.

Question 25

What connects the young to the mother’s placenta?

Answer 25

The umbilical cord

Question 26

What is the gestation period for placental mammals generally?

Answer 26

Usually, the larger the placental mammals, the longer the gestation period. For example, the gestation period for an elephant is about 21 months, but for a mouse, it’s only about 20 days.

Question 27

Placental mammals are classified into groups based on what?

Answer 27

Based on characteristics such as how they eat and how their bodies move.

Question 28

Give three examples of groups of placental mammals.

Answer 28

Rodents, carnivores, marine mammals

Question 29

Why are most young mammals dependent on one or both parents after they’re born?

Answer 29

Because most young mammals are usually quite helpless for a long time after being born. For example, many are born without a coat of insulating for. Their eyes are often sealed and may not open for weeks.