Download Animals are the most physically diverse kingdom of

KEY CONCEPT
Animals are diverse but share common
characteristics.
The Kingdoms of Life
18.5 Five Kingdoms (cont.)
• The kingdom Animalia contains heterotrophic
multicellular eukaryotes that develop from embryos.
The invertebrates—animals that have exoskeletons
and jointed legs—may be the majority of all
multicellular species.
The vertebrates—animals with a spinal column, or
backbone—are another large group of animals.
Most members of this kingdom reproduce sexually, are
motile, or capable of locomotion, and have senses
and nervous systems.
Each animal phylum has a unique body plan.
• Vertebrates have an internal segmented backbone.
• Invertebrates do not have a backbone.
• Arthropods make up most of the invertebrates.
Animals are the most physically diverse kingdom of
organisms.
• Animals range in size from 25-meter-long blue whales
to microscopic rotifers.
• Animals are found nearly everywhere on Earth.
All animals share a set of characteristics.
• All animals share a unique set of derived
characters.
• Animal cells are
supported by collagen.
– three-stranded
protein
– found in bone,
skin, ligaments,
fingernails,
and hair
Animals are grouped using a variety of criteria.
•
Criteria are used to categorize animals.
– Body plan symmetry
– Feeding
– Respiration
– Circulation
– Excretion
– Response
– Reproduction
gastrovascular
cavity
mouth
mesoglea
brain
muscle
hearts
blood vessels
oral arms
mouth
segment
digestive track
nerve cord
tentacles
• There are two types of body plan symmetry.
– bilateral symmetry: body divides equally along one plane
Animals with bilateral
symmetry can be
divided equally along
only one plane, which
splits an animal
into mirror-image
sides.
• There are two types of body plan symmetry.
– bilateral symmetry: body divides equally along one plane
– radial symmetry: body arranged in circle around a
central axis
Animals with radial symmetry
have body parts arranged in a
circle around a central axis.