Chapter 40

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

PowerPoint Lectures for Biology, Seventh Edition

Neil Campbell and Jane Reece

Lectures by Chris Romero

Chapter 40Chapter 40

Basic Principles of Animal Form and Function


Anatomy & Physiology

• Anatomy – study of STRUCTURE

• Physiology – study of FUNCTION


Form and Function

• The comparative study of animals reveals that form and function are closely correlated

Figure 40.1


Convergent Evolution in Animals

• Evolutionary convergence reflects different species’ independent adaptation to a similar environmental challenge

Figure 40.2a–e

(a) Tuna

(b) Shark

(c) Penguin

(d) Dolphin

(e) Seal


Exchange with the Environment

• An animal’s size and shape have a direct effect on how the animal exchanges energy and materials with its surroundings

• Exchange with the environment occurs as substances dissolved in the aqueous medium diffuse and are transported across the cells’ plasma membranes


• A single-celled protist living in water has a sufficient surface area of plasma membrane to service its entire volume of cytoplasm

Figure 40.3a

Contact with the Environment

Diffusion

(a) Single cell


Contact with the Environment

• Multicellular organisms with a sac body plan have body walls that are only two cells thick, facilitating diffusion of materials

Figure 40.3b

Mouth

Gastrovascularcavity

Diffusion

Diffusion

(b) Two cell layers


Contact with the EnvironmentExternal environment

Food CO2 O2Mouth

Animalbody

Respiratorysystem

Circulatorysystem

Nutrients

Excretorysystem

Digestivesystem

Heart

Blood

Cells

Interstitialfluid

Anus

Unabsorbedmatter (feces)

Metabolic wasteproducts (urine)

The lining of the small intestine, a diges-tive organ, is elaborated with fingerlikeprojections that expand the surface areafor nutrient absorption (cross-section, SEM).

A microscopic view of the lung reveals that it is much more spongelike than balloonlike. This construction provides an expansive wet surface for gas exchange with the environment (SEM).

Inside a kidney is a mass of microscopic tubules that exhange chemicals with blood flowing through a web of tiny vessels called capillaries (SEM).

0.5 cm

10 µm

50 µ

m

Figure 40.4


• Animal form and function are correlated at all levels of organization

• Animals are composed of cells

• Groups of cells with a common structure and function

– Make up tissues

• Different tissues make up organs

– Which together make up organ systems

Function Correlates with Structure in Animal Tissues


• Different types of tissues

– Have different structures that are suited to their functions

• Tissues are classified into four main categories

– Epithelial, connective, muscle, and nervous

Tissue Structure and Function


Epithelial Tissue

EPITHELIAL TISSUE

Columnar epithelia, which have cells with relatively large cytoplasmic volumes, are often located where secretion or active absorption of substances is an important function.

A stratified columnar epithelium

A simplecolumnar epithelium

A pseudostratifiedciliated columnarepithelium

Stratified squamous epithelia

Simple squamous epitheliaCuboidal epithelia

Basement membrane

40 µm

Figure 40.5


Connective Tissue

CollagenousfiberElasticfiber

Chondrocytes

Chondroitinsulfate

Loose connective tissue

Fibrous connective tissue

100

µm

100 µm

Nuclei

30 µm

Bone Blood

Centralcanal

Osteon

700 µm 55 µm

Red blood cellsWhite blood cell

Plasma

Cartilage

Adipose tissue

Fat droplets

150

µm

CONNECTIVE TISSUE

Figure 40.5


Muscle and Nervous Tissue

MUSCLE TISSUESkeletal muscle

100 µm

Multiplenuclei

Muscle fiber

Sarcomere

Cardiac muscle

Nucleus Intercalateddisk

50 µm

Smooth muscle Nucleus

Musclefibers

25 µm

NERVOUS TISSUE

Neurons Process

Cell body

Nucleus

50 µm

Figure 40.5


Lumen ofstomach

Mucosa. The mucosa is anepithelial layer that linesthe lumen.

Submucosa. The submucosa isa matrix of connective tissuethat contains blood vesselsand nerves.

Muscularis. The muscularis consistsmainly of smooth muscle tissue.

0.2 mm

Serosa. External to the muscularis is the serosa,a thin layer of connective and epithelial tissue.

• In all but the simplest animals different tissues are organized into organs

• In some organs the tissues are arranged in layers

Organs and Organ Systems

Figure 40.6


Body Cavities in Mammals

• Thoracic: houses lungs, heart

• Abdominal: “guts” – stomach, liver, intestines, pancreas, reproductive organs of females, bladder

– In higher animals, thoracic and abdominal cavities separated by diaphragm

– Both cavities are lined by mesentery – connective tissue that binds and supports organs


Thoracic Cavity


Abdominal Cavity


• Representing a level of organization higher than organs organ systems carry out the major body functions of most animals

Organ Systems in Mammals

Table 40.1


• Animals use the chemical energy in food to sustain form and function

• All organisms require chemical energy for growth, repair, physiological processes, regulation, and reproduction

• The flow of energy through an animal, its bioenergetics, ultimately limits the animal’s behavior, growth, and reproduction – which determines how much food it needs

• Studying an animal’s bioenergetics tells us a great deal about the animal’s adaptations

Bioenergetics of Animals


• Animals harvest chemical energy from the food they eat. Once food has been digested, the energy-containing molecules are usually used to make ATP, which powers cellular work. After the energetic needs of staying alive are met any remaining molecules from food can be used in biosynthesis

Overview: Bioenergetics of an Animal

Figure 40.7

Organic moleculesin food

Digestion andabsorption

Nutrient moleculesin body cells

Cellularrespiration

Biosynthesis:growth,

storage, andreproduction

Cellularwork

Heat

Energylost infeces

Energylost inurine

Heat

Heat

Externalenvironment

Animalbody

Heat

Carbonskeletons

ATP


• An animal’s metabolic rate

– Is the amount of energy an animal uses in a unit of time

– Can be measured in a variety of ways

• An animal’s metabolic rate

– Is closely related to its bioenergetic strategy

Quantifying Energy Use


Quantifying Energy Use

• One way to measure metabolic rate is to determine the amount of oxygen consumed or carbon dioxide produced by an organism

Figure 40.8a, b

This photograph shows a ghost crab in arespirometer. Temperature is held constant in thechamber, with air of known O2 concentration flow-ing through. The crab’s metabolic rate is calculatedfrom the difference between the amount of O2

entering and the amount of O2 leaving therespirometer. This crab is on a treadmill, runningat a constant speed as measurements are made.

(a)

(b) Similarly, the metabolic rate of a manfitted with a breathing apparatus isbeing monitored while he works outon a stationary bike.


• Birds and mammals are mainly endothermic, meaning that

– Their bodies are warmed mostly by heat generated by metabolism

– They typically have higher metabolic rates

• Amphibians and reptiles other than birds are ectothermic, meaning that

– They gain their heat mostly from external sources

– They have lower metabolic rates

Endothermic & Ectothermic Animals


• The metabolic rates of animals

– Are affected by many factors

• Metabolic rate per gram

– Is inversely related to body size among similar animals

Influences on Metabolic Rate


• The basal metabolic rate (BMR)

– Is the metabolic rate of an endotherm at rest

• The standard metabolic rate (SMR)

– Is the metabolic rate of an ectotherm at rest

• For both endotherms and ectotherms

– Activity has a large effect on metabolic rate

Activity and Metabolic Rate


• In general, an animal’s maximum possible metabolic rate is inversely related to the duration of the activity

Figure 40.9

Max

imum

met

abol

ic r

ate

(kca

l/min

; log

sca

le)

500

100

50

10

5

1

0.5

0.1

A H

A H

A

AA

HH

H

A = 60-kg alligator

H = 60-kg human

1second

1minute

1hour

Time interval

1day

1week

Key

Existing intracellular ATP

ATP from glycolysis

ATP from aerobic respiration

Maximum Metabolic Rate in Animals


• Different species of animals use the energy and materials in food in different ways, depending on their environment

• An animal’s use of energy is partitioned to BMR (or SMR), activity, homeostasis, growth, and reproduction

Energy Budgets

Endotherms Ectotherm

Ann

ual e

nerg

y ex

pend

iture

(kc

al/y

r)

800,000 Basalmetabolicrate

ReproductionTemperatureregulation costs

Growth

Activitycosts

60-kg female humanfrom temperate climate

Total annual energy expenditures (a)

340,000

4-kg male Adélie penguinfrom Antarctica (brooding)

4,000

0.025-kg female deer mousefrom temperateNorth America

8,000

4-kg female pythonfrom Australia

Ene

rgy

expe

nditu

re p

er u

nit

mas

s (k

cal/k

g•da

y)

438

Deer mouse

233

Adélie penguin

36.5

Human

5.5

Python

Energy expenditures per unit mass (kcal/kg•day)(b)Figure 40.10a, b


Regulating & Conforming: Homeostasis

• Animals regulate their internal environment within relatively narrow limits

• The internal environment of vertebrates

– Is called the interstitial fluid, and is very different from the external environment

• Homeostasis is a balance between external changes

– And the animal’s internal control mechanisms that oppose the changes


• Regulating and conforming

– Are two extremes in how animals cope with environmental fluctuations

• An animal is said to be a regulator

– If it uses internal control mechanisms to moderate internal change in the face of external, environmental fluctuation

• An animal is said to be a conformer

– If it allows its internal condition to vary with certain external changes

Regulating and Conforming


Mechanisms of Homeostasis• Mechanisms of homeostasis moderate changes in the internal

environment

• A homeostatic control system has three functional components: a receptor, a control center, and an effector

Figure 40.11

Response

No heatproduced

Roomtemperaturedecreases

Heaterturnedoff

Set point

Toohot

Setpoint

Control center:thermostat

Roomtemperatureincreases

Heaterturnedon

Toocold

Response

Heatproduced

Setpoint


Positive/Negative Feedback and Homeostasis

• Most homeostatic control systems function by negative feedback

– Where buildup of the end product of the system shuts the system off

• A second type of homeostatic control system is positive feedback

– Which involves a change in some variable that triggers mechanisms that amplify the change


Control of Body Temperature – Negative Feedback


Thermoregulation

• Thermoregulation contributes to homeostasis and involves anatomy, physiology, and behavior

• Thermoregulation is the process by which animals maintain an internal temperature within a tolerable range

• Ectotherms include most invertebrates, fishes, amphibians, and non-bird reptiles

• Endotherms include birds and mammals


• In general, ectotherms tolerate greater variation in internal temperature than endotherms

Ectotherms

Figure 40.12

River otter (endotherm)

Largemouth bass (ectotherm)

Ambient (environmental) temperature (°C)

Bod

y te

mpe

ratu

re (

°C)

40

30

20

10

10 20 30 400


• Endothermy is more energetically expensive than ectothermy

– But buffers animals’ internal temperatures against external fluctuations

– And enables the animals to maintain a high level of aerobic metabolism

Endotherms


• Mammals regulate their body temperature

– By a complex negative feedback system that involves several organ systems

Feedback Mechanisms in Thermoregulation

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