Characteristics of animals
 Feeding- Must consume food. Does not produce it’s
own food. Heterotrophic
 Respiration- Takes in oxygen and gives off CO2
 Circulation-Has a means to distribute O2
 Excretion- Means to eliminate waste
 Response –Respond to environment using specialized
cells
 Movement-Able to move from one place to another.
Mobile
 Reproduction- Able to reproduce sexually
 Eukaryotic- Cell with cell membrane and true nuclei.
Development of animals
1.
2.
3.
4.
5.
Fertilization- sperm and egg join together
(1n+1n=2n)
Mitosis of 2n cell = 2 cells, 4 cells, 8 cells,.16…32…….
Now get a hollow ball of cells called a BLASTULA
that is filled with fluid
One side of blastula pinches inward to form
GASTRULA
Hole that forms is called BLASTOPORE
BLASTULA
GASTRULA
Animals Grouped by Fate of
Blastopore
 Depending on what becomes of blastopore animals are
divided into 2 groups
 1. blastopore becomes mouth- PROTOSTOME(then
second opening becomes anus)
 2. blastopore becomes anus –DEUTEROSTOME(then
second opening is mouth)
 Cells then differentiate for animal to reach adulthood.
 Gastulation is what forms
an inside and an outside of
the organism.
 Inside layer called
ENDODERM-becomes
lining of the gut
 Outside layer of cells called
ECTODERM-becomes
skin and nervous system
 Some animals have a 3rd
middle layer called
MESODERM-becomes
the circulatory system,
muscle system, and
excretory system
Symmetry
 Animals can be divided into groups by their symmetry.
Asymmetry
 No symmetry
 Asymmetrical
 sponges
Radial symmetry
 Organism can be divided
along any plane
 Jellyfish
Bilateral Symmetry
 Organism has left and right
 Anterior and posterior
 Front and Back
 Ventral and Dorsal
Animals with 3 body layers
 Animals with 3 body layers(Ectoderm,Endoderm, and
Mesoderm) can be divided into 3 groups depending on
how much of their body cavity is covered by
mesoderm.
 Body cavity is called COELOME
Acoelomate
 No body cavity.
 Digestive tract runs length of body
 Flatworms
 Solid all the way through
Pseudocoelomate(false cavity)
 Space between endoderm and mesoderm is filled with fluid
 Coelome not compltely covered by mesoderm, just partially
 1 way digestive tract
 Round worm
Coelomate(true body cavity)
 True body cavity all surrounded by mesoderm
 Fluid filled
 Contains specialized organs
 Humans, Earthworm
Cephalization
 Concentration of sense organs and nerve cells in the
anterior region.
 Shows high degree of complexity
Feeding and Digestion
 Intracellular-inside each cell.
 Extracellular- food is broken down in digestive cavity
or tract. Then nutrients are absorbed
Respiration
 Exchange of gasses. Oxygen and Carbon Dioxide
 Lungs and gills have larger surface areas( alveoli and
slits) in order to have more contact with air or water.
Circulation
Open System
Closed System
 Blood is partially contained
 Blood is pumped by heart or
in vessels .Fluid is pumped
into spaces or sinuses where
organs are bathed in the fluid
for oxygen exchange.
 Ex- grasshopper
heart like organ through
vessels throughout the body
 Ex- Humans
Excretion
 Removal of metabolic
waste while controlling
the amount of water(
osmoregularity)
 Ammonia, Urea , Uric
Acid- depends on animal
Response
 Nervous systems gather stimuli from environment and
produce a response.
 Centralization- nerve cells concentrated in one area
 Cephalization- nerve tissue found in anterior region
 Specialization- complex animals have sense organs
that detect specific stimuli, like eyes detect light, ears
detect sound waves.
Movement and Support
 Hydrostatic Skeletons:
muscles surround a fluid
filled cavity like an
earthworm.
Exoskeleton: outer
covering made of chitin
found in insects. Must molt
occasionally due to
increase in body size.
Endoskeleton: support
system located inside the
body. Can allow for greater
size.
Reproduction
 Asexual: copy of parent- Fragmentation, budding
 Sexual: combination of 2 different gametes
 External Fertilization: Egg fertilized outside of female
body
 Internal Fertilization: Egg fertilized inside of female
body.