13.4 Hot and cold

• Biologie
• Middelbare school
• havo
• Leerjaar 3

This chapter

ST CH13 (thursday april 25th)

BT CH13 + CH14 in the testweek

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13.4 Hot and cold

• Welcome!
  
• Learning objectives
• Instruction

 - Warm-blooded and cold-blooded

 - Stay warm

 - Cooling down

 - Desert plants

• End of class

Learning objectives

• You will learn how animals are adjusted to cold or hot circumstances.

• You will also learn how plants are able to survive in a dry environment.

 30 sec per question!

15 seconden per vraag!

3 questions about previous paragraphs + 3 questions about 13.4

How are oxygen and carbon dioxide transported through an insect's body?

1. By air
2. By bloodcells
3. By water

Water with dissolved substances flows through plants.

Water with nutrients flows up and down through...

1. Xylem vessels
2. Phloem vessels

Humans have..

1. An open single circulatory system
2. An open double circulatory system
3. A closed single circulatory system
4. A closed double circulatory system

Energy is being ... during respiration.

1. used
2. produced

A house thermostat is usually set to approximately 20 ˚C.
What temperature is the thermostat in your brain set to?

1. 36˚C
2. 37˚C
3. 38˚C
4. 39˚C

How does your body stay warm?

1. Blood vessels widen + goosebumps
2. Blood vessels widen + shivering
3. Blood vessels narrow + goosebumps
4. Blood vessels narrow + shivering

Discuss with your neighbour without opening your books

What is the difference between warm-blooded and cold-blooded animals? 

Warm-blooded = a more or less constant body temperature

Cold-blooded = body temperature varies with that of the environment

Warm-blooded animals

Adaptations to the cold

- insulation = retain or trap heat 

• stagnant air between hairs or feathers
  
• fat layer in aquatic animals

- more respiration

- special behavior (winter rest and hibernation)

Winter rest

• wakes up once in a while
• Its body temperature, heart rate and respiratory rate decreases.

Hibernation

• reserve supply of fat
• sleeps from late autumn up until spring
• Its body temperature, heart rate and respiratory rate decreases.

Warm-blooded animals

Adaptations to the heat

- air current

- panting

- cold environment

Body surface area and cooling down

Small dog: 1 cubes with 6 sides of body surface area

Big dog: 8 cubes with 24/ 48 sides of body surface area 

(lower surface-area-to-volume ratio)

Desert plants

• wax layer
  
• small surface area
• sunken stomata
• hairs of spines
  
• small leaves

What?	Make: 13.4 assignments 1-3, 5, 7, 8, 10-12, 14, 15, 18, 19, 22
How?	In your (online) book. You are allowed to help your neighbour.
Help?	Ask your neighbour first. If you can't figure out the anwser together, then raise your hand.
Time?	15 minutes
Finished?	Well done! Check your answers. Then make a summary of 13.3 and 13.4.

What did you learn?

1. - What is the difference between cold-blooded and warm-blooded animals?
2. - How are warm-blooded animals adapted to the cold?
3. - How are warm-blooded animals adapted to the heat?
4. - How are desert plants adapted to the dry conditions?

Don't pack your bags yet!

Stay seated until the bell rings

Don't forget to push your char under the table