Chapter 6 – Obtaining energy

Key words Section 1 Section 2 Section 3 Carnivore Cellular Respiration Circulatory System Herbivore Diffusion Heart Omnivore Respiratory System Open Circulatory System Filter feeder Gill Closed Circulatory System Radula Lung Capillary Digestion Atrium Digestive system Ventricle Anus Excretory System Crop Kidney Gizzard Urine Intestine Esophagus Stomach

How Animals Obtain Food What animals eat – the different ways that an animal obtains food depends on what it eats and its adaptations for getting food. Most animals are Herbivores, Omnivores, or Carnivores Herbivores – eat only plant material Omnivores – eat both plant and animal materials Carnivores – eat only other animals A few types of animals – such as earthworms, snails and crabs eat decaying plants and animals

Animal Mouthparts Depending on their mouthparts, animals may eat by tearing, chewing, sucking or filtering their food. Example: grasshoppers have sharp mouthparts that tear and chew leaves. Many other animals have teeth, which are specialized for eating certain types of foods. Herbivores, such as rabbits have flat teeth. Carnivores, like wolves have teeth sharp enough for tearing. Some animals that live in water strain their food from the water, they are known as filter feeders. They eat microscopic organisms.

Animal Mouthparts - Examples

Adaptations for obtaining food Animals have amazing adaptations for obtaining food, which includes structures and behaviors. Structurally animals have an opening through which food enters their bodies. Behaviors like those of spiders, help to obtain food. Spinning of a web to help capture their prey.

How do animals digest food? The food that animals eat are to large to enter into cells, so first it must be broken down. Some types of animals digest food mainly inside their cells, but most animals digest food outside their cells. Sponges and a few other animals digest food inside specialized cells in their bodies. The digested food then diffuses into other cells, where it is used. This is known as Intracellular Digestion. Most animals digest their food outside their cells. This process is called extracellular digestion. Digestion outside cells occurs in the digestive system. Most carnivores and omnivores have digestive systems.

Digestive Tube Complex animals have digestive systems that consist of a tube with two openings. One opening is a mouth for taking in food and the other opening is an anus through which wastes leave. A digestive tube has specialized areas where food is processed for digestion, digested and absorbed. A digestive system with two openings is more efficient than a system with one opening because digested food does not mix with undigested food. Some animals have specialized digestive systems that meet their needs. Example: birds have a crop, where they can store food for long flights.