The document provides an overview of the key body systems in animals: digestive system, respiratory system, circulatory system, excretory system, nervous system, musculoskeletal system, and reproductive system. It describes the basic functions of each system, such as the digestive system being responsible for feeding, the respiratory system for respiration, and so on. Examples are given for different types of feeding, respiration, circulation, movement, and reproduction among animals.

1. Checklist of Body Systems Feeding (digestive system) Respiration (respiratory system) Internal transport (circulatory system) Excretion (excretory system) Response (nervous system) Movement (musculoskeletal system) Reproduction (reproductive system) *See “Unit Outline –Animalia/Organized Systems” handout for more detail and body systems colour coding These are often the same

2. Feeding – Digestive System Herbivores – animals that eat plants (e.g. roots, stems, leaves, flowers, fruits, or fluids in plants) Carnivores – organisms that eat animals or any part of their prey (e.g. fat, muscle, bone marrow, or blood) Parasites – live an feed either inside or attached to outer surfaces of other organisms; usually harm their host(s) Filter feeders – aquatic animals that strain tiny plants and animals from the water Detritus feeders – feed on small bits of decaying plants and animals (called detritus )

3. Respiration – Respiratory System Living cells consume oxygen and release carbon dioxide in the process of cellular respiration Animals must respire, or breathe, to take in and release these gases Small animals living in water or moist soil  respire through skin Large active animals  respiratory systems have evolved to take many different forms in adaptations depending on the animal’s habitat Respiration through the skin is not efficient enough for large animals

4. Internal Transport – Circulatory System Some aquatic animals (e.g. small worms) can function without an internal transport system Most animals must transport oxygen, nutrients, and wastes to and from the cells within its body Many multicellular animals have evolved a circulatory system with a pumping organ (heart) that forces blood through blood vessels Circulatory systems can be simple or complex E.g. Clam circulatory system

5. Response – Nervous System Animals must survey their surroundings to find food, spot predators, and identify other members of their species Animals use specialized cells called nerve cells which together compose a nervous system Sense organs (e.g. eyes, ears) gather info from the environment by responding to light, sound, temperature, and other stimuli Brain (nervous system control centre) processes this info and regulates how the animal responds

6. Movement – Musculoskeletal System Some animals are sessile  live their adult lives attached to one spot Most animals are motile  they move around In order to move, most animals use tissues called muscles that generate force by contracting Muscles often work together with a skeleton (system of solid support in the body) Exoskeleton - skeleton on the outside of the body (e.g. insects) Endoskeleton – skeleton on the inside of the body (e.g. reptiles, birds, and mammals) muscles + skeleton = musculoskeletal system

7. Reproduction – Reproductive System Animal species must reproduce to survive Different methods of reproduction: asexual sexual live young lay eggs direct development indirect development

8. Reproduction – Reproductive System lay eggs direct development indirect development Babies look like miniature adults. They increase in size as they grow older, but do not change overall form. Eggs hatch into larvae (immature stages that do not look like adults). As larvae grow, they undergo metamorphosis where they change shape dramatically. e.g. grasshopper e.g. butterfly continued…

9. Checklist of Body Systems Feeding (digestive system) Respiration (respiratory system) Internal transport (circulatory system) Excretion (excretory system) Response (nervous system) Movement (musculoskeletal system) Reproduction (reproductive system) *See “Unit Outline –Animalia/Organized Systems” handout for more detail and body systems colour coding These are often the same