Block D Part 3: Mammals and Adaptations to their Environment

Question 1

Name 3 common features of mammals.

Answer 1

Four chambered hearts (with atria and ventricles)
Warm-blooded (endotherms) with high and constant body temperature
Muscular diaphragm used in breathing
Single-boned lower jaw
Three bones in the middle ear
Hair at some point in development
Milk-producing glands in females
(Lecture 3, Slide 4)

Question 2

What are the three types of mammals?

Answer 2

Monotremes
Marsupials
Placentals
(Lecture 3, Slide 6)

Question 3

How are mammals classified?

Answer 3

Based on how offspring are produced and how the young develop
(Lecture 3, Slide 6)

Question 4

How do monotremes reproduce and develop?

Answer 4

In eggs
(Lecture 3, Slide 7)

Question 5

Is the embryo in marsupials developed when born?

Answer 5

No
(Lecture 3, Slide 8)

Question 6

Where does the embryo go to develop after birth in marsupials?

Answer 6

Its mother’s pouch
(Lecture 3, Slide 8)

Question 7

What does the mother’s pouch of a marsupial contain?

Answer 7

The nipples for milk
(Lecture 3, Slide 8)

Question 8

Where does the embryo develop in placentals?

Answer 8

In the female uterus
(Lecture 3, Slide 9)

Question 9

Where does a placental embryo gain oxygen and nutrients from and how?

Answer 9

The placenta, via the blood
(Lecture 3, Slide 9)

Question 10

How is waste material from a placental embryo removed?

Answer 10

Via the placenta
(Lecture 3, Slide 9)

Question 11

When is a placental embryo retained in the body until?

Answer 11

Until it reaches an advanced state of development
(Lecture 3, Slide 9)

Question 12

What do mammals do in cold conditions?

Answer 12

Retain body heat and body temperature (core temp)
(Lecture 3, Slide 10)

Question 13

What do mammals do in warm conditions?

Answer 13

Limit water loss and maximise ingested water
(Lecture 3, Slide 10)

Question 14

What do mammals do in low oxygen conditions?

Answer 14

Maximise oxygen intake
(Lecture 3, Slide 10)

Question 15

What do mammals do when seasons vary?

Answer 15

Reduce metabolism to maintain body head in the winter (winter dormancy)
Torpor or aestivation in the summer (summer dormancy)
(Lecture 3, Slide 10)

Question 16

What are 2 examples of things a mammal (such as a polar bear) does in cold conditions in order to retain body heat and core temperature?

Answer 16

Insulating layers (such as a fur coat)
Small surface area : volume ratio (to minimise heat loss)
White camouflage
Large feet to distribute load on ice
(Lecture 3, Slide 12)

Question 17

What is the human body’s primary method of cooling the body in periods of extreme heat?

Answer 17

Sweating
(Lecture 3, Slide 13)

Question 18

How can mammals obtain water from their food?

Answer 18

Produced from the metabolic breakdown of food
(Lecture 3, Slide 14)

Question 19

Why is it a bad idea for mammals to drink sea water?

Answer 19

They could end up ingesting 3X the salt found in blood
(Lecture 3, Slide 14)

Question 20

What are 3 things a mammal (such as a camel) may do to adapt to heat?

Answer 20

Adaptations to kidneys to prevent water loss
Sweat glands - to make sweating rare
Large surface area: volume ratio to maximise heat loss
Large flat feet, slit-like nostrils, double row of eyelashes and thick eyebrows
Thick top layer fur (adaptation to cold nights)
Hump for storage of fat (broken down for water)
(Lecture 3, Slide 15)

Question 21

What is the first step of salt and water management in mammalian kidneys?

Answer 21

Glomerular filtration
(Lecture 3, Slide 16)

Question 22

What is involved in the glomerular filtration step of salt and water management in mammalian kidneys?

Answer 22

Blood passes through the biological microfilter in the glomerulus part of the kidney.
Water and small molecules like salt pass though the filter, but larger molecules, as well as blood cells, don’t
(Lecture 3, Slide 16)

Question 23

Water is the second step in the salt and water management in mammalian kidneys?

Answer 23

Reabsorption
(Lecture 3, Slide 16)

Question 24

What is involved in the reabsorption stage in the salt and water management in mammalian kidneys?

Answer 24

The filtered plasma passed through a long tube called the Loop of Henle, where the water is reabsorbed
(Lecture 3, Slide 16)

Question 25

What occurs after the reabsorption stage in salt and water management in mammalian kidneys?

Answer 25

Concentration of the fluid and formation of urine (Lecture 3, Slide 17)

Question 26

How do marine and desert animals produce more concentrated urine?

Answer 26

They have a longer Loop of Henle (Lecture 3, Slide 18)

Question 27

What are 2 ways in which mammals (such as marine mammals) adapt to low oxygen levels.

Answer 27

Efficient exchange of air at the water surface, take up of more oxygen in blood cells and storage in muscles, reduction of blood supply to the extremities Slow heart rate to conserve oxygen and ensure flow to vital organs Anaerobic respiration takes place in muscles Higher concentrations of haemoglobin and myoglobin (Lecture 3, Slide 19)

Question 28

What, other than oxygen can bind to haemoglobin (Hb)?

Answer 28

Carbon dioxide (Lecture 3, Slide 21)

Question 29

What is PO2?

Answer 29

Partial pressure of oxygen; the amount of oxygen gas dissolved in the blood (Lecture 3, Slide 22)

Question 30

What does high PO2 cause haemoglobin to do?

Answer 30

Take up oxygen (Lecture 3, Slide 22)

Question 31

What does low PO2 cause haemoglobin to do?

Answer 31

Drop oxygen (Lecture 3, Slide 22)

Question 32

What are 3 things that shift the dissociation curve of haemoglobin to the right?

Answer 32

Carbon dioxide, decrease in pH and rise in temperature (Lecture 3, Slide 24)

Question 33

What is myoglobin (Mb)?

Answer 33

A small oxygen carrying pigment found in muscle tissues (Lecture 3, Slide 25)

Question 34

What does myoglobin consist of?

Answer 34

A single polypeptide chain of 153 amino acids and a single haem prosthetic group (Lecture 3, Slide 25)

Question 35

What is the role of myoglobin?

Answer 35

It stores oxygen and facilitates oxygen diffusion in contracting muscle tissue (Lecture 3, Slide 25)

Question 36

When does myoglobin release oxygen?

Answer 36

During periods of hypoxia (deficiency in the amount of oxygen reaching the tissues) or anoxia (severe hypoxia) (Lecture 3, Slide 25)

Question 37

State 3 ways in which a mammal can adapt to variation in seasons.

Answer 37

Conservation of energy when food supplies become scarce Slowing down of metabolism and heart rate Oxygen consumption falls (breathing slows) Dropping body temperature (regulated hypothermia) Regulation of enzyme activity (Lecture 3, Slide 26)

Question 38

What is torpor?

Answer 38

A hypometabolic state (35% of basal metabolic rate) (Lecture 3, Slide 27)

Question 39

What is torpor regulated by?

Answer 39

Circadian rhythm (Lecture 3, Slide 27)

Question 40

How often can torpor occur?

Answer 40

Can occur daily for a few hours (Lecture 3, Slide 27)

Question 41

What are circadian rhythms?

Answer 41

Psychological and behavioural characteristics that follow a daily, or circadian pattern (Lecture 3, Slide 28)

Question 42

How does jet lag effect circadian rhythms?

Answer 42

Results in phase shifts as a result of travelling across time zones (Lecture 3, Slide 28)