Download 34-1

34-1 The Nature of Animals
Vertebrate
* Animal with backbone.
Invertebrate
*Animal without backbone.
These make up more than 95%
of all animal species.
Characteristics of Animals
 Multicellular
organization
 Heterotrophs
 Sexual reproduction
Have movement
1. Multicellular Organization
dults have 50 trillion cells
Specialization: adaptation of
cells for a particular function
Cell junctions: the formation
of tissue from many individual
cells which are held together by
these connections.
2. Heterotrophy
 Ingestion, take in organic
matter then digestion.
3. Sexual Reproduction and
Development
ygote: first cell of new
individual
Differentiation: an enlarging
mass of dividing cells
become different from each
other
4. Movement
 Results from
interrelationship of two
tissues, nervous and muscle.
Neurons transmit the
information and muscles
contract and respond.
Origin and Classification
First animals arose in the
sea
Invertebrates were first
multicellular animal and
evolved from protists