Chapter 4 - Temperature

Question? Along the shoreline of Lake Michigan in Michigan, fruit trees are grown in abundance. These plants are not found 20 or 30 miles inland from the lake. Why?

Chapter 4 - Temperature Objectives: 1. Identify where heat comes from and where is goes!!! 2. Describe how organisms compensate for variations in environmental temperatures 3. List similarities and differences between ectotherm and endotherm 4. Define resting stages and their applications

Temperature - The Formula H s = H m + H cd + H cv + H r + H e Where: H s = Total heat stored in body H m = Heat gained from metabolism H cd = Heat gained or lost from conduction H cv = Heat gained or lost from convection

Temperature - The Formula H s = H m + H cd + H cv + H r + H e Where: H r = Heat gained or lost through electromagnetic radiation H e = Heat lost through evaporation

Fig. 4.13

Thermal Control Organisms can control body temperature by: Amount of surface area exposed to sun Amount of body surface exposed to cooler/warmer surfaces Thermal conductivity of body surface (fluff fur or feathers

Thermal Control Amount of stored chemical energy released by metabolism Amount of water evaporated from the body Amount of sunlight reflected from their surface

Physiological Response to Temperature Organisms whose body temperature varies in directly with environmental temperatures - Don’t you mean: cold-blooded?

Poikilotherms Animals--- many aquatic: clams, worms, insect larvae, barnacles, Plants--- aquatic: phytoplankton, Others--- bacteria, fungi

Poikilotherms Advantages: Can allocate more energy to growth and reproduction Can colonize areas of limited food and water Expending no energy maintaining a temperature different than the environment

Poikilotherms Disadvantages: Activities restricted to warmer days and seasons Limited ability to colonize colder regions

Ectotherms Organisms that rely on external sources of heat to regulate body temperature, usually a combination of behavior, and anatomy

Ectotherms How does this happen? Plants: Orientation to or away from the sun, pigmentation (radiation) Loss of water through leaves (evaporation) Altering wind patterns using growth forms (convection)

Fig. 4.14

Fig. 4.15

Fig. 4.16

Ectotherms Animals: Similar to plants-body size, shape, and pigmentation One big advantage- Animals can move to find different microclimates to best suite their needs

Fig. 4.17

Endotherms Similar to ectotherms; that is, they use the environment to warm and cool the body. But-- Rely extensively on metabolic heat to regulate the body temperature.

Endotherms Below what temperature do you need to put on a coat? Above what temperature would you like to have air conditioning?

Endotherms Thermal neutral zone: Range of temperature over which metabolic rate of endotherm does not change “ Comfort Zone ”

Fig. 4-21

Endotherms Advantages: Can maintain activity over a wide range of temperatures Efficient respiration enables long periods of activity Can colonize a wide range of environments, including e.g., polar regions

Endotherms Disadvantages: Must expend energy to maintain body temperature May require large amounts of water to maintain body temperature in hot environments

Endotherms Regulate their body temperature within a narrow range, independent of the environment - Homeotherms e.g., mammals and birds ~ C Warm-blooded????

Endotherms Organisms that control their body temperature some of the time, while allowing it to be controlled by the environment other times- Heterotherms e.g., animals that hibernate - bats, marmots, hummingbirds, But Not Bears

Reducing Metabolic Rate What is it? A state of low metabolic rate and low body temperature. Organisms rely on stored energy reserves. “Torpor”

Reducing Metabolic Rate/Temperature Daily or for several hours at a time: “Torpor” e.g., hummingbirds Extended period of time in winter “Hibernation” e.g., marmots Extended period of time in summer: “Estivation” e.g., turtles

Fig. 4.29

Assignment For Thursday Read Chapter 5 - Water Relations

Did we learn anything today? 1. Identified how some organisms compensate for variations in environmental temperatures 2. Know what the terms ectotherm, endotherm, homeotherm, heterotherm mean 3. Understand hibernation and torpor