What is an Animal?

1
What is an Animal?

• Chapter 25
• Biology
• Auburn High School
• p. 692 711

2
Main Ideas of the Chapter

• Animals are heterotrophs, digest their food
  inside the body, typically have a type of
  locomotion, and are multicellular
• Animals have no cell wall
• Embryonic development form a fertilized egg is
  similar in many animal phyla.

3
Main Ideas of the Chapter

• Animals have a variety of body plans and types of
  symmetry that are adaptations
• Animals may be asymmetrical, radially
  symmetrical, or bilaterally symmetrical
• A coelom is a fluid-filled body cavity that
  supports internal organs
• Flatworms and other acoelomate animals have
  flattened, solid bodies with no body cavities

4
Main Ideas of the Chapter

• Animals such as roundworms have a pseudocoelom, a
  body cavity that develops between the endoderm
  and mesoderm.
• Coelomate animals such as humans and insects have
  internal organs suspended in a body cavity that
  is completely surrounded by mesoderm
• Exoskeletons provide a framework of support on
  the outside of the body, whereas endoskeletons
  provide internal support.
• Animals probably evolved from colonial protists
  in the Cambrian period

5
25.1 Typical Animal Characteristics

• p. 693 699

6
Characteristics of Animals

• All animals are
• Eukaryotic, multicellular organisms
• heterotrophic
• have tissues that form organs
• glycogen is form of starch storage
• Must have a methods for obtaining food
• Sessile animals that dont move from place to
  place

7
Characteristics of Animals

• Must digest food in order to obtain its nutrients
• Some animals digest their food in individual
  cells
• Other animals digest their food in an internal
  cavity
• Animal cells are adapted for specific functions
• Example blood cells, nerve cells and muscle cells

8
Development of Animals

• Most develop from single, fertilized egg called a
  zygote

9
25.2 Body Plans and Adaptations

• p. 700 - 705

10
What is Symmetry?

• Symmetry refers to a balance in proportions of an
  object or organism.
• Types
• Asymmetry
• animal that is
  irregular in shape
• Most are sessile
• Example is a sponge

11
What is Symmetry?

• Radial symmetry
• Can be divided along any plane, through a central
  axis, into roughly equal halves
• Adaptation of hydra

12
What is Symmetry?

• Bilateral symmetry
• Can be divided down its length into similar right
  and left halves
• Terms anterior (head end) posterior (the tail
  end) dorsal (back surface) ventral (belly
  surface)
• Example is a crawfish

13
Body Cavities in Animals

• Acoelomate
• Animals that have 3 cell layers but no body
  cavities
• Example- flatworm
• There is no space between the gut and epidermis
  in the acoelomate body plan.

14
Body Cavities in Animals

• Pseudocoelom
• A fluid-filled body cavity partly lined with
  mesoderm
• Example roundworm
• There is space between the gut and epidermis in
  the pseudocoelomate body plan.
• The body cavity is not lined with a membrane.

15
Body Cavities in Animals

• Coelomate
• A fluid-filled space that is completely
  surrounded by mesoderm
• Example segmented worm
• There is space between the gut and epidermis in
  the coelomate body plan.
• The body cavity is lined with a membrane that
  attaches to organs.

16
Animal Protection and Support

• Exoskeleton
• A hard, waxy covering on the outside of the body
  that provides a framework for support
• Also provides protection
• Prevents water loss

17
Animal Protection and Support

• Endoskeleton
• An internal skeleton that provides support inside
  an animals body
• Protects internal organs
• Provides a surface for muscles to pull against

18
Animal Protection and Support

• Invertebrate
• An animal that does not have a backbone
• Examples crabs, spiders, grasshoppers, and
  echinoderms

19
Animal Protection and Support

• Veterbrate
• An animal with a backbone.
• All are bilaterally symmetrical, with
  endoskeletons
• Examples snakes, humans, fish, birds, reptiles