Introduction to Animals Chapter 26

General Features of Animals Animals are multicellular, heterotrophic organisms with cells that lack cell walls. Multicellular (made of more than one cell) Heterotrophs- organism that obtains food by eating other organisms. –Filter feeders = catch particles of food that drift by in the water.

Movement Animals are unique among living things because animals can move rapidly and in complex ways. Swim, walk, run, and fly. Locomotion is a big advantage for animals: –Finding food –Avoiding predators

Kinds of Animals Kingdom Animalia contains about 35 major divisions called phyla. Animals are often informally grouped as invertebrates or vertebrates, although vertebrates make up only a subgroup of one phylum (Chordata). The vast majority of animals are invertebrates.

Invertebrates Include any animal that does not have a backbone. Most primitive = sponges Advanced = ants, octopuses. Can form the basis of an entire ecosystem.

Vertebrates Chordates that have a backbone. Many of the animals you see in a zoo: –Lions, elephants, turtles, snakes, and birds. Have a cranium and an internal skeleton Backbone supports and protects a dorsal nerve cord. Also provides a site for muscle attachment.

Assignment Pg. 626, 1-4 Read section 2 Pg. 630, 1-6

Animal Body Systems Allows animals to function Not all animals have every body system Body systems reflect/shape the lifestyles that animals have

Support An animals skeleton provides a framework that supports the animal’s body. The skeleton is also vital to an animals movement. Hydrostatic skeleton – a cavity that is filled with water and that has a support function Endoskeleton – an internal skeleton made of bone and cartilage Exoskeleton – a hard, external, supporting structure that develops from the ectoderm

Digestive and Excretory Systems The digestive system is responsible for extracting energy and nutrients from an animal’s food. The excretory system removes waste products from the animal’s body.

Digestive System Gastrovascular cavity – a digestive cavity that serves both digestive and circulatory purposes in some animals. Single-celled organisms do not have a digestive system. Other animals have a digestive tract with two openings.

Excretory System Waste products such as ammonia will hurt or kill an organism if they are not removed. Terrestrial animals need to minimize water loss. Simple aquatic invertebrates and some fishes excrete ammonia through their skin or gills.

Nervous System The nervous system carries information about the environment through the body and coordinates responses and behaviors. 1.Simple Nervous System 2.Complex Nervous System

Respiratory and Circulatory Systems The respiratory system is responsible for exchanging oxygen and carbon dioxide between the body and the environment. The circulatory system transports gases, nutrients and other substances within the body.

Reproduction The two types of reproduction in animals is asexual and sexual. –Asexual occurs when an individual produces exact copies of itself and does not mix its genes with those of others. –Sexual occurs with a new individual is formed by the union of a male and female gamete.