Campbell Biology 14Th Chapt 40 Part Ii

Front 1

Thermoregulation

Back 1

Process by which animals maintain an internal temp within a normal range

Involves form, function, and behavior

Front 2

Endothermic

Back 2

Animals that generate heat by metabolism (birds and mammals)

Can maintain a stable body temp even in face of large fluctuations in environmental temps

Is more energetically expensive than ecto

Front 3

Ectothermic

Back 3

Animals gain heat from external sources (most invertebrates, fishes,amphibians, and Nonavian reptiles)

In general, tolerate greater variation in internal temp

Front 4

Poikilotherm

Back 4

Body temp varies with its environment (conformer)

Heat source and body temp are not fixed (not all poikilotherms are ectotherms)

Front 5

Homeotherm

Back 5

Body temp is constant (regulator)

Again..not fixed

Front 6

Balancing heat loss and gain through 4 processes

Back 6

1. Radiation

2. Evaporation

3. Convection

4. Conduction

Front 7

Integumentary system

Back 7

Skin, hair, nails, horns..items on outside that help in heat regulation

Front 8

5 adaptations that help thermoregulate

Back 8

1. Insulation

2. Circulatory

3. Cooling by evaporation

4. Behavioral responses

5. Adjusting metabolic heat production

Front 9

Insulation

Back 9

Major thermoregulatory adaptation in mammals and birds

Skin, fur, blubber (doesn’t need more food bc of blubber) reduce heat flow btw an animal and it environment (animals stand up their fir to trap heat)

Especially important to marine mammals (bc heat travels in water faster) like walruses and whales

Front 10

Circulatory adaptations

Back 10

Regulation of blood flow near the surface significantly affects thermoregulation

Many endotherms and some ectotherms can alter the amount of blood flowing btw body core and skin

Vasodilitaion and vasconstriction

(Rabbit and elephant ears)

Front 11

Vasodilation and vasoconstriction

Back 11

Vasodilation: blood flow in skin increases, facilitating heat loss

Vasoconstriction: blood flow in skin decreases, lowering heat loss

Front 12

Countercurrent system exchange (circulatory adaptation)

Back 12

Artery going away from heart and vein going towards the heart are next to each other

While artery blood (warmed up) is traveling down to foot, it is giving off heat to the vein that has cooler blood, thus warming the blood going back to the heart (which is almost completely warm)

This does not warm the foot bc the artery blood is losing heat as it goes down.

Some Sharks, fishes and insects use this

Front 13

Coping by evaporation

Back 13

Many types of animals lose heat through evaporation of water from their skin

Sweating or bathing moistens the skin, helping to cool and animal down

Panting increases the cooling effect in birds and many mammals

Front 14

Behavioral responses

Back 14

Ectotherms (endotherms at times) use behavior to control temp

They seek warm places when cold and orient themselves toward heat sources

When hot they bathe or move to cooler areas to change orientation

ie: dragonfly orients body to avoid heat, bees huddle for heat and bring water in to cool hive

Front 15

Adjusting metabolic heat

Back 15

Thermogenesis: increased muscle activity such as moving and shivering

Birds and some reptiles raise body temp by shivering (chickadees shiver themselves warm in -40 degrees)

Nonshivering thermogenesis: when hormones cause mitochondria to increase their metabolic activity instead of creating ATP

Front 16

Brown fat

Back 16

Mammals have tissue that is designed for rapid heat production

It is found in infant mammals and hibernating mammals

Amount of brown fat in adults has been found to vary on temp of environment

Front 17

Acclimatization in thermogenesis

Back 17

Bird and mammals can vary their insulation to seasonal temps

Lipid composition of cell membranes may change with temps

Some cells Allan produce enzymes (like antifreeze) that can prevent freezing in cells

Front 18

Hypothalamus

Back 18

Thermostat for the body

Triggers heat loss or heat generating mechanisms (shivering or blood vessel change)

Front 19

Fever

Back 19

Increase in normal range for bio thermostat

Change in set point to kill infection

Ectotherms actually seek higher temps to heat body more to kill infection

Front 20

Bioenergetics

Back 20

Overall flow and transformation of energy in an animal

It determines an animals nutritional needs and it relates to the size activity and environment of the animal

Front 21

Energy allocation and use

Back 21

Organisms can be classified by how they obtain chemical energy

Autotroph: plants, harness light energy to build molecules

Heterotrophs: animals, harvest chemical energy from food

Front 22

Biosynthesis

Back 22

After needs ofbstaying alive are met, remaining food molecules are used in biosynthesis

Growth and repair

Synthesis of Storage of material such as fat

Production of gametes

Front 23

Metabolic rate

Back 23

Sum of all the energy an animals used in a unit of time

Front 24

Determine metabolic rate by...

Back 24

Animals heat loss

Amount of oxygen or carbon dioxide produced

Measuring energy content of food consumed and energy lost in waste products

Front 25

Basal metabolic rate va standard metabolic rate

Back 25

Basal: Metabolic rate of an endotherm at rest at a comfortable temp

Standard: rate of an ectotherm at rest at a specific temp

Both rates assume a nongrowing, fasting, and nonstressed animal

Ectotherms have lower rates than endotherms of a comparable size (BMR for humans is 1300-1800 kcal/day, but SMR for an alligator is 60 kcal/day at 20•C

Front 26

Influences on metabolic rate

Back 26

Age, sex, size, activity, temp, and nutrition

Front 27

Size and metabolic rate

Back 27

Proportional to the body mass to the power of 3 quarters (m^3/4)

Smaller animals have a higher metabolic rate per gram than larger animals (need more oxygen, faster heart rate, more blood volume as compared with a larger animal)

ie: each gram of a mouse has 20x calories than a gram of an elephant

Front 28

TP analogy with metabolic rate

Back 28

D

Front 29

For most terrestrial animals..rate of consumption

Back 29

Average daily rate of energy consumption is 2 to 4 times BMR or SMR

Fractions of an animals energy budget devoted to activity depends on: Environment, behavior, size, mechanism of thermoregulation

ie: compare penguin and python. Penguin has red pie devoted to thermoregulation but python does not. The little mouse devotes a lot more to thermoregulation even though it is smaller

Front 30

Torpor

Back 30

Physiological state of decreased activity and metabolism

Enables animals to save energy while avoiding difficult and dangerous conditions (severe conditions)

hibernation is long term torpor that is an adaptation to winter cold and food scarcity

Front 31

Hibernation

Back 31

Can be 20 times lower than if an animal tried to keep normal temp

Molecular components of bio clock stop oscillating

Front 32

Estivation

Back 32

Summer torpor

Enables animals to survive long periods of high temps and scarce water

Daily torpor is exhibited by many small animals

Front 33

Circadian clock and hibernation

Back 33

Looking at 2 genes associated with day and night cycles

Levels of per2 are high during the day and goes down at night

Levels of bmal as wel

Front 34

Remember

Back 34

Structure function relationships

Fundamental similarities in evolution