Brief Introduction to the Animal

Kingdom

• Vocabulary

– Vertebrate

– Invertebrate

– Detritivore

– Asymmetry

– Bilateral symmetry

– Radial symmetry

– Cephalization

• Key Concepts

– What are the characteristics of an animal?

– What are essential functions for animals to survive?

– Cephalization

– Coelum

– Pseudocoelum

– Acoelomates

– Blastula

– Blastophore

– Protosome

– Deuterosome

Which of these are “animals”?

• Characteristics all animals share:

– Eukaryotic

– Multicellular

– Heterotrophic– Heterotrophic

– Reproduce sexually

• Have specialized tissue that forms nerves and

muscles

• Cells do not have a cell wall

• Diversity in the Animal kingdom is so vast and the differences among the organisms are great

– Therefore, animals are divided into two major groups

• Invertebrates

Invertebrates

• Invertebrates

– Organisms without a backbone

• Vertebrates (Chordates)

– Organisms with a backbone

• 95% of all animals are invertebrates while 5% are vertebrates

Vertebrates

How do animals obtain food?

• Herbivore = eats plants

• Carnivore = eats animals

• Omnivore = eats plants and animals

• Detritivore = feed on decaying organic material• Detritivore = feed on decaying organic material

• Filter Feeders = aquatic animals that strain food from water

• Parasite = lives in or on another organism

• Scavenger = consumes carcasses of other organisms

• Respiration

– All animals take in oxygen and

give off carbon dioxide

– Respire through lungs, gills,

skin, or simple diffusion

• Circulation• Circulation

– Smaller animals depend on

diffusion

– Larger animals depend on a

circulatory system

• Excretion:– Primary waste product is ammonia

• Response:– Receptor cells = sound, light, external – Receptor cells = sound, light, external

stimuliNerve cells => nervous system

• Movement:– Most animals move

• Reproduction

– Most reproduce sexually = genetic diversity

– Many invertebrates can also reproduce asexually

to increase their numbers rapidlyto increase their numbers rapidly

Body Symmetry

• Body Symmetry– the body plan of an animal, how its

parts are arranged

• Types of Symmetry– Asymmetry - no pattern (corals, – Asymmetry - no pattern (corals,

sponges)

– Radial Symmetry - shaped like a wheel (starfish, hydra, jellyfish)

– Bilateral Symmetry - has a right and left side (humans, insects, cats, etc)

• Cephalization - an anterior concentration of

sense organs (to have a head)

– Animals with bilateral symmetry tend to exhibit

cephalization

• The more complex the animals becomes the

more pronounced their cephalizationmore pronounced their cephalization

Body Sides

• anterior - towards the head

• posterior - towards the tail

• dorsal - back side

• ventral - belly side• ventral - belly side

• Segmentation

– "advanced" animals have body segments, and

specialization of tissue (even humans are

segmented, look at the ribs and spine)segmented, look at the ribs and spine)

Segmented

Body Cavity

• Most animals have some type of body cavity

– A fluid-filled space between digestive tract and

body wall

– Allows digestive organs to grow– Allows digestive organs to grow

• Coelum (prounounced “see lum”)

– Body cavity that develops within the mesoderm

and is completely lined with tissue derives from

mesoderm

– More complex organisms have

• Pseudocoelum

– Body cavity is partially lined with

mesoderm

– Example: Pinworm

• Acoelomate• Acoelomate

– Organism lacks body cavity all

together

– Examples: Jellyfish, tapeworms

Animal Development

• Early Development

– Animals begin life as a zygote (fertilized egg)

• The cells in the zygote divide to form the

BLASTULA - a hollow ball of cells

• The blastula pinches inward to form three GERM LAYERS

– Ectoderm: Outermost layer

• Develops into the sensory organs, nerves, outer layer of “skin”

– Mesoderm: Middle layer

• Develops into the muscles, most of the circulatory system, reproductive system, and excretory organ systemreproductive system, and excretory organ system

– Endoderm: Innermost layer

• Develops into the digestive system and much of respiratory system

• Blastophore: digestive tract that only has one

opening to outside

• Protosomes: an animal whose mouth is formed

from the blastophorefrom the blastophore

– Example: most invertebrates

• Deuterosomes: an animal whose anus is formed

from the blastophore and the mouth is formed

for a second opening later in development

– Examples: Echinoderms and Chordates

Animal Kingdom Phyla

• Phylum Porifera –

sponges

• Phylum Cnidaria – sea

anemones, jellyfish,

hydra

• Phylum Platyhelminthes -Flatworms (e.g. tapeworms, planarian)

• Phylum Nematoda –roundworms (e.g. pinworm)

Tap

ew

orm

Pin

wo

rm

pinworm)

• Phylum Annelida -segmented worms (e.g. earthworms)

Pin

wo

rmE

arth

wo

rm

• Phylum Molluska – clams, squid snails

• Phylum Arthropoda- crustaceans, insects,

spiders

– This is the largest phylum in the animal kingdom

and contains the most number of species

• Phylum Echinodermata – starfish

• Phylum Chordata – all vertebrates