Introduction to the Animal Kingdom

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Which of these is an “animal”?

Answer: They are all animals!

Characteristics of Animals: • eukaryotic• multicellular • heterotrophic• lack cell walls• motile at some point in lifespan• develop from a blastula early in lifecycle

(hollow ball of cells)• most reproduce sexually with diploid stage

being dominant stage

Biology = study of lifePhysiology = Study of the functions of organs

Anatomy = the structure of the organism/organs

Zoology = study of animals

Animal Functions1.Feeding strategies:

Herbivore = eats plants Carnivore = eats animals Omnivore = eats plants and animals Detritivore = feed on decaying organic

material Filter Feeders = aquatic animals that

strain food from water

Parasite = lives in or on another organism (symbiotic relationship)

Scavenger = eats things that have been killed

2. Respiration:

Take in O2 and give off CO2 Lungs, gills, through skin, simple diffusion

3. Circulation:Very small animals rely on diffusionLarger animals have circulatory system

4. Excretion:Primary waste product is ammonia

5. Response:Coordinate their activities with Receptor cells = sound, light, external stimuliNerve cells => nervous system

6. Movement:* Most animals move

7.  Reproduction:  Most reproduce sexually = genetic diversity Many invertebrates can also reproduce asexually to increase their numbers rapidly

Body Plan-how animal’s parts are arranged and organized; structural blueprint

Body Symmetry:•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)

Identify the Symmetry

Body Sidesanterior - toward the headposterior - toward the taildorsal - back sideventral - belly side

Levels of Organization• In multicellular organisms cells have become

specialized to perform a specific function.

• Groups of specialized cells that work together are referred to as a tissue – there are 4 animal tissues (epithelial, connective, muscular, nervous)

• Groups of tissues can form organs.

• Organs can work together in systems – organ systems to carry out specific functions

Cephalization - an anterior concentration of sense organs (to have a head)

*The more complex the animal becomes the more need for connection of nervous tissue and receptors at the anterior/head end of body to allow for rapid movement and processing stimuli

Octopus – member of the class Cephalopoda (head-foot)

Segmentation-"advanced" animals have body segments – repeating parts -different segments like head, thorax, abdomen have become specialized for specific function

Embryological Development

Early DevelopmentAnimals 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/body layers.

(middle) (outer)

(inner)

Give rise to outer skin and nerves.

Give rise to body systems i.e. circulatory, reproductive, excretory, muscular

Give rise to gut.

Coelom – body cavity

Digestive tract/gut

with one or two openings; a tube system

- develops mouth first

- develops anus first

Limbs: legs, flippers and wings• Animals with bilateral symmetry

and cephalization also tend to have paired external appendages or limbs

• Limbs may be used for movement, defense or gathering sensory information.

e.g. antennae, mouthparts, wings, gills, legs, fins, arms, and certain parts of a tail

Animal Kingdom • Like plants the early ancestor of the animals moved

from water onto land.

• Major evolutionary milestones are marked by changes in the body plan.

• There are about 35 animal phyla but 9 major ones.

• However one common way to group animals is whether they have a backbone – vertebrates = 5% or the absence of a backbone – invertebrates = 95%

Animal Kingdom Phyla

Phylum Porifera – sponges

Phylum Cnidaria – sea anemones, jellyfish, hydra

Phylum Platyhelminthes - flatworms

Free-living Planarian Parasitic Tapeworm

Phylum Annelida – segmented worms

Phylum Nematoda – roundworms

Phylum Mollusca – 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 – includes all vertebrates

Phylum Rotifera –microscopic aquatic animal

• Soft bodies therefore fossil record weak

• Filter feeders – omnivorous – primary consumers

• Most reproduce by pathogenesis