Zoology. An 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.
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Protista- some, unicellular, animal-like organisms(protozoans)
considered to be evol. precursors to animals
ANIMALIA- are ANIMALS
What is an Animal?
Are members of Kingdom Animalia
Lack cell walls
Usually have a method of
Most reproduce sexually
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:
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
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.
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.
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
Some animals live their entire lives attached to a single spot (sessile)
Most are motile meaning that they move
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
Bilateral: can be divided only one way to produce mirror image halves
Radial symmetry: can be divided along any plane to produce 2 halves which look alike
Asymmetrical: Has no definite shape.
Radial Symmetry: Body is arranged in a circle like the spokes of a wheel.
Bilateral Symmetry: If divided lengthwise in half, both sides will match.
Includes worms, insects & vertebrates
Have external body parts that repeat on
either side of the body
- close to the middle
How does this happen????
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
a. Acoelomates- no body cavity lined with mesoderm
b. Pseudocoelomates- partial body cavity lined with mesoderm
c. Coelomates- true body cavity lined with mesoderm