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Homeostasis: Thermoregulation

Homeostasis: Thermoregulation

Assessment

Presentation

Biology

11th Grade

Medium

NGSS
HS-LS1-3

Standards-aligned

Created by

Mr. Cavida

Used 85+ times

FREE Resource

16 Slides • 12 Questions

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Homeostasis: Thermoregulation

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Introduction

  • Why do lizards sunbathe? Why do jackrabbits have huge ears? Why do dogs pant when they're hot? Animals have quite a few different ways to regulate body temperature!

  • These thermoregulatory strategies let them live in different environments, including some that are pretty extreme.

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Introduction

  • Polar bears and penguins, for instance, maintain a high body temperature in their chilly homes at the poles, while kangaroo rats, iguanas, and rattlesnakes thrive in Death Valley, where summertime highs are over 38C.

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  • consists of a ‘heat loss centre’ and a ‘heat gain centre’

  • temperature-sensitive nerve cells (neurones) detect changes in the temperature of the blood flowing through the brain (internal stimuli)

  • thermoregulation centre of the hypothalamus also receives information via sensory nerves from temperature-sensitive receptors located in the skin (external stimuli), and in many internal organs​

The Hypothalamus as the Control Centre

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  • Thyroxin is an iodine-containing hormone produced in the thyroid gland.

  • On secretion it stimulates oxygen consumption and basal metabolic rate of the body organs.

  • Variation in secretion of thyroxin helps to control body temperature.

Another mechanism in thermoregulation

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Mechanisms of thermoregulation

  • Endotherms, such as birds and mammals, use metabolic heat to maintain a stable internal temperature, often one different from the environment.

  • Ectotherms, like lizards and snakes, do not use metabolic heat to maintain their body temperature but take on the temperature of the environment.

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Mechanisms of thermoregulation

  • Both endotherms and ectotherms have adaptations—features that arose by natural selection—that help them maintain a healthy body temperature. These adaptations can be behavioral, anatomical, or physiological.

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Mechanisms of thermoregulation

  • Some adaptations increase heat production in endotherms when it’s cold. Others, in both endotherms and ectotherms, increase or decrease exchange of heat with the environment.

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Categories of thermoregulatory mechanisms

  • Changing behavior

  • Increasing metabolic heat production

  • Controlling the exchange of heat with the environment

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Multiple Choice

Homeostasis
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allows for a wildly fluctuating internal environment

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is impossible in vertebrates

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is the maintenance of a relatively stable internal environment and often incorporates a form of feedback regulation

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is the maintenance of a relatively stable external environment and often incorporates a form of feedback regulation

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Multiple Choice

Sweats and pants to keep cool.
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endotherm
2
ectotherm

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Multiple Choice

Question image

Homeostatic cooling mechanisms include

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piloerection and panting

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panting and vasoconstriction

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sweating and piloerection

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sweating and vasodilation

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Multiple Choice

Shivering heats up the muscles and warms the blood flowing through them.

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TRUE

2

FALSE

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Multiple Choice

Slows down and hibernates when its cold.
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endotherm
2
ectotherm

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Multiple Choice

Maintaining body temperature is an example of a:
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negative feedback loop

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positive feedback loop

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Multiple Choice

What happens to the rate of an enzyme reaction when heated up?

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Increases

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Decreases

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Increase and then decreases

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decreases and then increases

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Multiple Choice

Temperature regulation center in the brain of a human

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hypothalamus

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thermoregulation

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receptor

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negative feedback

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Multiple Choice

Why is the bodies core temperature 37oC?

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Optimum temperature for enzymes

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No specific reason

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To limit the enzymes rate of reaction

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Its not 37oC

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Multiple Choice

Ectothermic organisms include

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birds and mammals

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reptiles, fish, amphibians, and all invertebrates

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Multiple Choice

An ectotherm's temperature is rapidly decreasing due to a sudden cold front and severe weather conditions. What is the organism most likely to do?

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Nothing, environmental conditions do not effect ectotherm's internal temperature.

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Nothing, the organism must learn how to survive the weather conditions anyway.

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Seek shelter from the storm in a cool place underground.

4

Seek shelter that provides warmth to increase the organism's temperature.

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Multiple Select

An endothermic organism is outside in the cold snow. What behavioral adaptations might they do to maintain their temperature? Select all that apply.

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Seek shelter because they cannot maintain their temperature.

2

Shiver to generate body heat.

3

Move around to increase blood flow.

4

Bask in the sun.

Homeostasis: Thermoregulation

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