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 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 Functions Feeding: Animals feed in a large variety of ways. Carnivore: Eats meat/animals ONLY Herbivore: Eats plants ONLY Omnivore: Eats meat & plants Detritivore: Feeds on plant and animal remains and other dead matter called detritus (Includes poop).
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
Essential Functions 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 Excretion: releasing liquid nitrogenous 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 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 Functions Movement: Some animals live their entire lives attached to a single spot (sessile) Most are motile meaning that they move
Essential Functions 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.)
Symmetry: balance in body proportions Body Plans of Animals Symmetry: balance in body proportions 3 Types Bilateral: can be divided only one way to produce mirror image halves Asymmetrical- Irregular shape Radial symmetry: can be divided along any plane to produce 2 halves which look alike
Asymmetrical: Has no definite shape. 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 Have external body parts that repeat on Includes worms, insects & vertebrates Have external body parts that repeat on either side of the body
What type of symmetry?
Body arrangements: 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 Body Cavities a. Acoelomates- no body cavity lined with mesoderm EX: flatworms
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
Checkpoint What are the main characteristics all animals share? Evidence suggests that animals evolved from ___________. What are the three animal body types? What are the three germ layers? What is the difference between a protostome and a deuterostome?
The End