ZoologyAn Introduction

Zoology

• Study of animals• In this class- Important Kingdoms-

Protista- some, unicellular, animal-like organisms(protozoans)

considered to be evol. precursors to animals

ANIMALIA- are ANIMALS• Latin “zoa” or “zo”- means animal

Kingdom Protista

• Single celled• Eukaryotic• Ingest or produce

food• Some animallike

What is an Animal?• Are members of Kingdom Animalia• Are multicellular• Are Eukaryotic • Are Heterotrophs• Lack cell walls

• Usually have a method of

movement

• Most reproduce sexually

• Require oxygen

What is an Animal?• Multicellular: Having more than one cell • Eukaryotic: Organisms whose cell

contain a nucleus

• Heterotroph: Organisms that obtains

energy from the foods it consumes; also

called a consumer.

2 Types of Animals• Invertebrates: Animals that do not

have a backbone or a vertebral column

• Vertebrates: Animals that has a

vertebral column, or backbone

What Animals Do to Survive

Animals carry out the following essential functions:

1. Feed

2. Respire

3. Circulation

4. Excrete

5. Respond

6. Move

7. Reproduce

Essential Functions2. Respiration: Whether they live in water or

on land, all animals respire, which means they take in oxygen and give off carbon dioxide.

– Some can rely on diffusion of these substances through their skin

– Most have evolved complex tissues and organ systems for respiration

Essential Functions3. Circulation: transport of nutrients

and wastes• Many aquatic animals (ex: aquatic worms) rely

solely on diffusion to transport oxygen & waste.

• Larger animals have some kind of circulatory system to move materials around within their bodies.

Essential Functions

4. Excretion: releasing wastes– A buildup of ammonia & other nitrogenous

wastes would kill an animal

– Animals have excretory system that either eliminates ammonia quickly or converts it into a less toxic substance(uric acid) that is removed from the body.

Essential Functions

5. Response: Animals respond to events in their environment using specialized cells called nerve cells.

– Some nerve cells are receptors that respond to sound, light, and other stimuli

– The arrangement of nerve cells in the body changes dramatically from phylum to phylum

– Simple animals- nerve cells, nerve net– Complex- nervous systems

Essential Functions6. Movement: • Some animals live their entire lives

attached to a single spot (sessile)• Most are motile meaning that they move

Essential Functions

7. Reproduction: Most reproduce sexually by producing gametes.

– Maintains genetic diversity in populations

– Helps species evolve when the environment changes

– Many reproduce asexually & allows to increase numbers rapidly (inverts.)

Body Plans of Animals

Symmetry: balance in body proportions

3 Types

Asymmetrical-

Irregular shape Radial symmetry: can be divided along any plane to produce 2 halves which look alike

Bilateral: can be divided only one way to produce mirror image halves

Symmetry

Asymmetrical: Has no definite shape.

Symmetry

Radial Symmetry: Body is arranged in a circle like the spokes of a wheel.

Symmetry

Bilateral Symmetry: If divided lengthwise in half, both sides will match.

Bilateral Symmetry • Includes worms, insects & vertebrates

• Have external body parts that repeat on

either side of the body

What type of symmetry?

Body arrangements:

a. anterior: head region(front on upright man)

b. posterior: tail region (back on upright man)

c. dorsal: back or top

d. ventral: abdomen(belly) or bottom

Anatomical Terms (cont)• Medial

- close to the middle

• Lateral– Close to the side or

movement away from middle

• Distal– Away from the main part

• Proximal– Close to the main part

Anatomical Terms (cont)

• Oral– End with the mouth

• Aboral– Opposite end of the mouth

• Cephalic– Toward head

• Caudal– Toward tail

Cephalization-concentration of sense organs- developed nervous system- “formation of head"

How does this happen????

Embryonic Development

STEP 1

STEP 2

Zygote cleaves to become blastula and then forms gastrula. The blastopore of the gastrula can become either the mouth or the anus of the organism

Protostomes vs. Deuterostomes

• Protostome- “first mouth” Blastopore becomes the mouth. Ex-Annelids, Mollusks and arthropods

• Deuterostome- “second mouth” Blastopore becomes anus.

Ex-echinoderms, hemichordates,chordates

Embryonic Development

• As embryo develops, three germ

layers form:

a. Ectoderm•  becomes nervous system, epidermis of the skin,

pituitary, lens of eye (outside layer)

b. Mesoderm•  becomes muscles, skeleton, notochord, circulatory

system, kidney, reproductive system (middle layer)

c. Endoderm

•  becomes lining of digestive tract, liver, pancreas,

epithelial lining of lungs, many endocrine glands (inside layerdigestive tract)

a. Acoelomates- no body cavity lined with mesoderm

• EX: flatworms

Body Cavities

b. Pseudocoelomates- partial body cavity lined with mesoderm

• “Tube within a tube” body plan

• EX: roundworms, rotifers

c. Coelomates- true body cavity lined with mesoderm

• EX: all other animals

Advantages of a body cavity (coelom or pseudocoelom):

• Fluid in cavity helps distribute food, wastes, hormones, etc. from one end of animal to the other

• Better distribution allows animal to grow larger • A place to put things, like new organs

THE ANIMAL KINGDOM OVERVIEW• Invertebrates-no backbone• Vertebrates or Chordates-backbone

Section 29-1

RadialSymmetry

Deuterostome Development

Coelom

Pseudocoelom

Protostome Development

RadialSymmetry

Three Germ Layers;Bilateral Symmetry

Tissues

Multicellularity

Chordates Echinoderms Arthropods

Annelids Mollusks

Roundworms

Flatworms

Cnidarians

Sponges

Single-celled ancestor

Invertebrate Cladogram

Checkpoint

1. What are the main characteristics all animals share?

2. Evidence suggests that animals evolved from ___________.

3. What are the three animal body types?

4. What are the three germ layers?

5. What is the difference between a protostome and a deuterostome?

The End