Introduction to the Animal Kingdom Notes
Most diverse kingdom in appearance
Each phylum has its own typical body plan (arrangement)
What is an Animal?
Animals are heterotrophic, eukaryotic, and multicellular and lack cell walls.
95% = invertebrates (do not have backbone)
5% = vertebrates (have a backbone)
There are 7 essential functions of animals:
Feeding:
Herbivore = eats plants
Carnivore = eats animals
Omnivore = eats plants and animals
Filter Feeders = aquatic animals that strain food from water
Parasite = lives in or on another organism (symbiotic relationship)
Respiration:
Take in O2 and give off CO2
Lungs, gills, through skin, simple diffusion
Circulation:
Very small animals rely on diffusion
Larger animals have circulatory system
Excretion:
Primary waste product is ammonia
Liquid waste
Nervous System Response:
Receptor cells = sound, light, external stimuli
Nerve cells => nervous system
Movement:
Most animals are motile (can move)
Muscles usually work with a skeleton
Reproduction:
Most reproduce sexually = this leads to genetic diversity
Many invertebrates can also reproduce asexually = to increase their numbers rapidly
Trends in Animal Evolution
Cell Specialization and Levels of Organization:
Cells -->tissues -->organs -> organ systems
Early Development:
Zygote = fertilized egg
Blastula = a hollow ball of cells
Blastopore = the blastula folds in creating this opening
Protostome = mouth is formed from blastopore
Deuterosome = anus if formed from blastopore
Anus = opening for solid waste removal from digestive tract
The cells of most animal embryos differentiate into three layers called germ layers
Endoderm = (innermost) develops into the lining of the digestive tract and respiratory
tract
Mesoderm = (middle) muscle, circulatory, reproductive, and excretory systems
Ectoderm = (outermost) sense organs, nerves, outer layer of skin
Body Symmetry:
Body Symmetry - the body plan of an animal, how
its parts are arranged
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)
*The more complex the animals becomes the more
pronounced their cephalization
anterior - toward the head
posterior - toward the tail
dorsal - back side
ventral - belly side
Segmentation - "advanced"
animals have body segments,
and specialization of tissue
(even humans are segmented,
look at the ribs and spine)
Body Cavity Formation: A fluid-filled space where internal organs can be suspended
Types of Animals
Phylum
Examples
Evolutionary Milestone
Porifera
sponges
multicellularity
Cnidaria
jellyfish, hydra, coral
tissues
Platyhelminthes
flatworms
bilateral symmetry
Nematoda
roundworms
pseudocoelom
Mollusca
clams, squids, snails
coelom
Annalida
earthworms, leeches
segmentation
Arthropoda
insects, spiders, crustaceans
jointed appendages
Echinodermata
starfish
deuterostomes
Chordata
vertebrates
notochord