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Kingdom Animalia
Review

Biology is the study of life…
– So what makes something living?
All living things must:
Be made up of at least 1 cell that contains
genetic material (DNA)
2. Reproduce
3. Grow (increase in size, mature, develop,
etc.)
4. Metabolize (have a need and use for
energy)
5. Respond to stimuli
6. Maintain stable internal environment
7. Change over time
1.
That’s all fine and good, but when do we
get to the animals?

Zoology- the study of animals
– Two Major Categories:
 Vertebrates-have a backbone
 Invertebrates-do not have a backbone
 Vertebrate or Invertebrate?
Characteristics of Animals

Multicellular

Eukaryotes (cells with nucleus & organelles)

Cells do not have a cell wall or chloroplast
Ingestive heterotrophs (take in food and
internally digest it)
About 800,000 species have been identified of
about an estimated 9 or 10 million that are
estimated to inhabit the earth.

~ Characteristics ~

Have a nervous system to respond to their
environment

Locomotion relates to ability to obtain food

Most animals develop from a zygote
becoming a

A single layer of cells surrounding a fluidfilled space forming a hollow ball of cells
called a gastrula.
Locomotion:
 Motile-can
move from one location to
another on their own
 Sessile-cannot move from place to
place, but do have moving parts
Sessile
Motile
~ Developmental Characteristics ~

The gastrula is made up of three parts:
– Ectoderm, a layer of cells on the outer surface
of the gastrula, grows and divides developing
into skin and nervous tissue.
– Endoderm, a layer of cells lining the inner
surface of the gastrula, develops into the
lining of the animal’s digestive tract.
– Mesoderm, made up of two layers of cells
lying between the ectoderm and endoderm,
forms muscles, reproductive organs and
circulatory vessels.
~ Developmental Characteristics ~

Animals that develop a mouth from the
indented space in the gastrula are
protostomes.

Animals that develop an anus from the
opening in the gastrula are
deuterostomes.
~ Body Plans ~

Animals that are
irregular in shape are
asymmetrical.

Animals that are
regular in shape are
symmetrical.
~ Body Plans ~

An animal is asymmetrical if it cannot be
divided into equal portions.

An animal has radial symmetry if it can be
divided along any plane, through a central
axis, into equal halves.

An animal has bilateral symmetry if it can be
divided down its length into similar right and
left halves forming mirror images of each
other.
Which figure has bilateral symmetry?
Which has radial symmetry?
Asymmetry
The most primitive animals are
asymmetrical
 Sponges are asymmetrical

Radial Symmetry
Animals with radial symmetry are usually
sessile, free-floating, or weakly swimming
 Like a wheel, animals with this spend most
of their time floating like a bouy or
attached to rocks
 They are different between their dorsal
(back) and ventral (belly) surfaces

Bilateral Symmetry
Most animal are bilateral
 they have an anterior (front) and posterior
(rear) end
 Advantage: if a body part is damaged, the
animal can rely on an identical part on its
other side
 Being bilateral provides balance and aids
in directional movement

Cephalization
Bilateral symmetry has usually led to
cephalization
 Cephalization is the process by which
sensory organs and appendages become
localized in the head end of animals

Evolutionary Trends

If we analyze the basic body plans of
animals, we find that they illustrate
evolutionary trends:
– Multicellular body plan
– Radially symmetrical body plan
– Bilaterally symmetrical body plan
– “tube-within-a-tube” body plan
– Cephalization
Body Cavity
Most animals have a body cavity, which is a fluidfilled space that lies between the digestive tract
and the body wall.
 A body cavity is important because it provides a
space in which internal organs can be suspended
so that they are not pressed on by muscles or
twisted out of shape by body movements.
 Body cavities also allow for specialized regions to
develop, and they provide room for internal
organs to grow and expand.
 In some animals, body cavities contain fluids that
are involved in circulation, feeding and excretion.

~ Body Plans ~

Acoelomates – animals have three cell
layers with a digestive tract but no body
cavities.

Pseudocoelomates – animals with a fluidfilled body cavity partly lined with
mesoderm.

Coelomates – animals with a body cavity
completely surrounded by mesoderm.
~ Protection and Support ~

Though not all animals have a skeleton, those
that do can be divided into two groups:
– Those with an exoskeleton – a hard, waxy
coating on the outside of the body that
protects internal organs, provides a
framework for support, and a place for
muscle attachment. A shell can also be an
exoskeleton
– Those with an endoskeleton – support
framework within the body that protects
some organs and a brace for muscles to pull
against. They are usually made of
cartiladge and/or bone
What Animals Do to Survive

All animals survive and respond to the
environment in different ways
– Animals carry out the following essential
functions: feeding, respiration, circulation,
excretion, response, movement, and
reproduction.
Feeding

Animals have evolved a variety of ways to
feed.
– Herbivores are animals that eat plants, including
roots, stems, leaves, flowers and fruits.
– Carnivores feed on other animals.
– Filter feeders are aquatic animals that strain tiny
floating plants and animals from the water around
them.
– Detrivores are animals that feed on pieces of
decaying plant and animal material called detritus.

Animals can also form symbiotic relationships,
in which two species come in close association
with each other.
Respiration

Whether they live in water or on land,
all animals respire.
– They take in oxygen and give off carbon
dioxide.
– Because of their very simple, thin-walled
bodies some animals can rely on the
diffusion of these substances through
their skin.
– Most have evolved complex tissues and
organ systems for respiration.
Circulation

Many small aquatic animals rely solely on
diffusion to transport oxygen, nutrients,
and waste products among all their cells.
– Diffusion

Larger animals, however, have some kind
of circulatory system to move materials
around within their bodies.
Excretion

Primary waste product= ammonia
– A build up of it can kill an animal.
– This makes excretion essential to life.
 Excretory system eliminates ammonia quickly or
converts it into a less toxic substance that is
removed from the body.
– These vary from group of cells that pump water
out of the body to complex organs such as
kidneys.
Response

Animals respond to events in their
environment using specialized cells called
nerve cells.
– In most animals, nerve cells hook up together
to form the nervous system.
– Some cells, called receptors, respond to
sound, light, and other stimuli.

The arrangement of nerve cells in the
body changes dramatically from phylum to
phylum.
Movement

Some animals live their entire adult lives
attached to a single spot.
– Most animals, however, are motile.

Others use muscles and a muscle
contractions to move around.
– Also use a skeleton.
Reproduction

Most reproduce sexually by producing
haploid gametes.
– Helps create and maintain genetic diversity in
populations.
 Helps improve species’ abilities to evolve when the
environment changes.

Many animals, especially invertebrates,
can reproduce asexually.
– Allows animals to increase numbers rapidly.
~Invertebrates~

8 main phyla

No backbones

95% of all animals are in this group
~ Phylum Chordata ~ subphylum Vertebrata
5 classes
 Fish
 Mammals
 Reptiles
 Amphibians
 Birds
Animal Taxa