What is an Animal?What is an Animal?

Chapter 25Chapter 25BiologyBiology

Auburn High SchoolAuburn High Schoolp. 692 – 711 p. 692 – 711

Main Ideas of the ChapterMain Ideas of the Chapter

Animals are heterotrophs, digest Animals are heterotrophs, digest their food inside the body, typically their food inside the body, typically have a type of locomotion, and are have a type of locomotion, and are multicellularmulticellular

Animals have no cell wallAnimals have no cell wall Embryonic development form a Embryonic development form a

fertilized egg is similar in many fertilized egg is similar in many animal phyla.animal phyla.

Main Ideas of the ChapterMain Ideas of the Chapter

Animals have a variety of body plans Animals have a variety of body plans and types of symmetry that are and types of symmetry that are adaptationsadaptations

Animals may be asymmetrical, radially Animals may be asymmetrical, radially symmetrical, or bilaterally symmetricalsymmetrical, or bilaterally symmetrical

A coelom is a fluid-filled body cavity A coelom is a fluid-filled body cavity that supports internal organsthat supports internal organs

Flatworms and other acoelomate Flatworms and other acoelomate animals have flattened, solid bodies animals have flattened, solid bodies with no body cavitieswith no body cavities

Main Ideas of the ChapterMain Ideas of the Chapter

Animals such as roundworms have a Animals such as roundworms have a pseudocoelom, a body cavity that develops pseudocoelom, a body cavity that develops between the endoderm and mesoderm.between the endoderm and mesoderm.

Coelomate animals such as humans and Coelomate animals such as humans and insects have internal organs suspended in a insects have internal organs suspended in a body cavity that is completely surrounded by body cavity that is completely surrounded by mesodermmesoderm

Exoskeletons provide a framework of support Exoskeletons provide a framework of support on the outside of the body, whereas on the outside of the body, whereas endoskeletons provide internal support.endoskeletons provide internal support.

Animals probably evolved from colonial Animals probably evolved from colonial protists in the Cambrian periodprotists in the Cambrian period

25.1: Typical Animal 25.1: Typical Animal CharacteristicsCharacteristics

p. 693 – 699 p. 693 – 699

Characteristics of AnimalsCharacteristics of Animals

All animals are:All animals are: Eukaryotic, multicellular organismsEukaryotic, multicellular organisms heterotrophicheterotrophic have tissues that form organshave tissues that form organs glycogen is form of starch storage glycogen is form of starch storage

Must have a methods for obtaining Must have a methods for obtaining foodfood Sessile – animals that don’t move from Sessile – animals that don’t move from

place to placeplace to place

Characteristics of AnimalsCharacteristics of Animals Must digest food in order to obtain its Must digest food in order to obtain its

nutrientsnutrients Some animals digest their food in Some animals digest their food in

individual cellsindividual cells Other animals digest their food in an Other animals digest their food in an

internal cavityinternal cavity Animal cells are adapted for specific Animal cells are adapted for specific

functionsfunctions Example: blood cells, nerve cells and Example: blood cells, nerve cells and

muscle cellsmuscle cells

Development of AnimalsDevelopment of Animals

Most develop from single, fertilized Most develop from single, fertilized egg called a zygoteegg called a zygote

25.2: Body Plans and 25.2: Body Plans and AdaptationsAdaptations

p. 700 - 705p. 700 - 705

What is Symmetry?What is Symmetry?

Symmetry refers to a balance in Symmetry refers to a balance in proportions of an object or organism.proportions of an object or organism.

Types:Types: Asymmetry – Asymmetry –

animal that is animal that is irregular in shapeirregular in shape

Most are sessileMost are sessile Example is a spongeExample is a sponge

What is Symmetry?What is Symmetry?

Radial symmetry Radial symmetry Can be divided Can be divided

along any plane, along any plane, through a central through a central axis, into roughly axis, into roughly equal halvesequal halves

Adaptation of Adaptation of hydrahydra

What is Symmetry?What is Symmetry?

Bilateral symmetryBilateral symmetryCan be divided down its length Can be divided down its length into similar right and left halvesinto similar right and left halves

Terms: anterior (head end); Terms: anterior (head end); posterior (the tail end); dorsal posterior (the tail end); dorsal (back surface); ventral (belly (back surface); ventral (belly surface)surface)

Example is a crawfishExample is a crawfish

Body Cavities in AnimalsBody Cavities in Animals

AcoelomateAcoelomate Animals that have 3 Animals that have 3

cell layers but no cell layers but no body cavitiesbody cavities

Example- flatwormExample- flatworm There is no space There is no space

between the gut between the gut and epidermis in and epidermis in the acoelomate the acoelomate body plan.body plan.

Body Cavities in AnimalsBody Cavities in Animals

PseudocoelomPseudocoelom A fluid-filled body A fluid-filled body

cavity partly lined with cavity partly lined with mesodermmesoderm

Example: roundwormExample: roundworm There is space There is space

between the gut and between the gut and epidermis in the epidermis in the pseudocoelomate pseudocoelomate body plan. body plan.

The body cavity is not The body cavity is not lined with a lined with a membrane.membrane.

Body Cavities in AnimalsBody Cavities in Animals

CoelomateCoelomate A fluid-filled space A fluid-filled space

that is completely that is completely surrounded by surrounded by mesodermmesoderm

Example: segmented Example: segmented wormworm

There is space There is space between the gut and between the gut and epidermis in the epidermis in the coelomate body plan. coelomate body plan.

The body cavity is The body cavity is lined with a lined with a membrane that membrane that attaches to organs.attaches to organs.

Animal Protection and Animal Protection and SupportSupport

ExoskeletonExoskeleton A hard, waxy covering A hard, waxy covering

on the outside of the on the outside of the body that provides a body that provides a framework for supportframework for support

Also provides Also provides protectionprotection

Prevents water lossPrevents water loss

Animal Protection and Animal Protection and SupportSupport

EndoskeletonEndoskeleton An internal skeleton An internal skeleton

that provides that provides support inside an support inside an animal’s bodyanimal’s body

Protects internal Protects internal organsorgans

Provides a surface Provides a surface for muscles to pull for muscles to pull againstagainst

Animal Protection and Animal Protection and SupportSupport

InvertebrateInvertebrate An animal that does An animal that does

not have a not have a backbonebackbone

Examples: crabs, Examples: crabs, spiders, spiders, grasshoppers, and grasshoppers, and echinodermsechinoderms

Animal Protection and Animal Protection and SupportSupport

VeterbrateVeterbrate An animal with a An animal with a

backbone.backbone. All are bilaterally All are bilaterally

symmetrical, with symmetrical, with endoskeletonsendoskeletons

Examples: snakes, Examples: snakes, humans, fish, birds, humans, fish, birds, reptilesreptiles