Introduction to Animal Form & Function

Prepared by: Ms. IRISH M. SEQUIHOD

OBJECTIVES• Reflect animal form and function to Biology’s major theme.• Explain the principle of Complementarity.• Discuss the rationale of body plans in relation to external

environment.• Discuss the concept of Homeostasis.• Describe the different forms of chemical energy harvest of life

forms.

Animal form reflects Biology theme

•Structure and function•Emergent properties•Evolution (natural selection)•Regulation

Function Correlates with Functions

•Complementarity Principle•Life characterized by hierarchical levels of organization, each with emergent properties.•Hierarchical Structure•Organized but complex

Function Correlates with Functions

Structural Organization

Organism

systems organs tissues cell molecular

The Organ Systems of Animal are Interdependent

The Organ Systems of Animal are Interdependent

Body plans and the External Environment

• An animal’s size and shape, features that biologists often call body plans or designs, are fundamental aspects of form and function that significantly affect the way an animal interacts with its environment.• The body plan or design of an animal

results from a pattern of development programmed by the genome, itself the product of millions of years of evolution due to natural selection.

Physical laws constrain animal form

Body size and shape affect interactions with

the environment.

Body size and shape affect interactions with the environment.

Regulating the Internal Environment

• Mechanisms of Homeostasis moderate changes in the internal environment.• Homeostasis means “steady state” • Homeostasis – depends on feedback circuits

negative feedback – a change in a variable being monitored triggers the control mechanism to counteract further change in same direction.

positive feedback – a change in some variable triggers mechanisms that amplify rather than to reverse the change.

Negative Feedback

Positive Feedback

Introduction to the Bioenergetics

• According to source of energy• According to carbon source• Animals are heterotrophs that harvest

chemical energy from the food they eat.• Plants are autotrophs that they harvest

chemical energy from carbon dioxide, water, and sunlight.

Introduction to the Bioenergetics

• After the energetic needs of staying alive are met, any remaining food molecules can be used in biosynthesis, including body growth and repair, synthesis of storage material such as fat, and production of reproductive structures, including gametes.

Introduction to the Bioenergetics

•Metabolic rate provides clues an animal’s bioenergetic “strategy”.• The flow of energy through an animal - the

animal’s bioenergetics – ultimately sets the limits to the animal’s behaviour, growth, and reproduction and determines how much food it needs.•Metabolic rate – the amount of energy an

animal uses in a unit of time.

Two Basic Bioenergetic “strategies”

• Endothermic - bodies are warmed by heat generated by metabolism, and their body temperature must be maintained at a certain level to sustain life.

Two Basic Bioenergetic “strategies”• Ectothermic - do not produce enough metabolic

heat to have much effect on body temperature.

Metabolic Rate vs. Body Size & Condition

•Metabolic rate per gram is inversely related to body size among similar animals.•Animals adjust their metabolic rates

as conditions change.•Basic Metabolic Rate (BMR) vs.

Standard Metabolic Rate (SMR)

Metabolic Rate vs. Body Size & Condition

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

Metabolic Rate vs. Body Size & Condition

• Both an alligator (ectotherm) and a human (endotherm) are capable of very intense exercise in short spurts of a minute or less.

Metabolic Rate vs. Body

Size & Condition

Energy budgets reveal how animals use energy and materials