Download Chapter 26-1 Introduction to the Animal Kingdom

Chapter 26-1
Introduction to the Animal Kingdom
What is an animal?
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Members of the Kingdom Animalia
Multicellular
Eukaryotic cells whose cells lack a cell wall
Heterotrophs
• Animals have:
i. Epithelial tissue - covers the body surfaces,
lines the inside of tubes found in the body
and form the glands of an animal.
-cells tend to be thin, flat structures
through which gases and nutrients can
move
through.
ii. Muscle tissue
iii. Connective tissue
iv. Nervous tissue
• 95% of animals are categorized as
invertebrates.
-range in size from microscopic dust mites
to the giant squid which is more than 20
meters long.
-include sea stars, sponges, jelly fish,
worms, insect, clams.
-5% of animals are categorized as vertebrates
- includes fishes, amphibians, reptiles, birds
and mammals.
What do animals do to survive?
Essential functions include:
1. Feeding.
2. Respiration
3. Circulation
4. Excretion
5. Response
6. Movement
7. Reproduction.
• Homeostasis
is often maintained by internal feedback
mechanisms called feedback loops.
Feedback loops involve feedback inhibition in
which the product or result of a process
stops or limits the process.
Ex. When a dog becomes to hot it pants –
panting releases heat – body temperature of the
dog cools – dog stops panting.
1. Feeding
-Absorb food, ingest food?
-Herbivore, carnivore, amnivore, detrivore?
-Filter feeder?
-Symbiotic relationship/ parasisitic?
2. Respiration
Transport of Oxygen and Carbon dioxide.
Aquatic or Terrestrial?
Simple system of diffusion or a Complex
system involve different organs?
3. Circulation
Transport of gases, nutrients and
waste
products.
Aquatic vs Terrestial animals?
Simple diffusion vs circulatory
system?
4. Excretion
Elimination of waste products
-Ammonia, urea, uric acid – elimination
of excess nitrogen.
-elimination of excess salts, water
5. Response
-responding to external environment
Specialized nerve cells? Nervous System
-responding to internal environment
Hormones?
6. Movement
Sessile? Motile?
Cilia? Flagella? Muscle cells? Muscle
System? Skeleton?
7. Reproduction
Asexually? Sexually?
Trends in Animal Evolution
• Complex animals tend to have high levels
of cell specialization and internal body
organization, bilateral symmetry, a front
end or head with sense organs and a body
cavity.
Early Development
• Animals that reproduce sexually begin life
as a Zygote ( 2n) or fertilized egg (2n).
• Embryology is the study of embryo
development
• Draw out diagram from text p 661
Blastula – hollow ball of cells which develops
into either a protostome or deuterostome
Blastula – formation of a blastopore – inward
indentation of the blastula in the centre of
the blastula – this tube becomes the
digestive tract and is formed in one of two
ways:
• 1. Protosome
-mouth is formed from the blastospore – incl
most invertebrates.
2. Deutrosome
-an animal whose anus is formed through the
blastospore – the mouth is formed 2nd after
the anus.
-includes echinoderms and all vertebrates
During early development, the cells of the embryo
develop (differentiate) into three layers called germ
layers.
Endoderm – inner most germ layer – develop into the
linings of the digestive and much of the respiratory
organ systems.
Mesoderm - middle layer – differentiates into
muscles and much of the circulatory, reproductive
and excretory organ systems
Ectoderm - outermost layer – gives rise to sense
organs, nerves and the outer layer of skin.
Body Symmetry
-except sponges
1. Radial Symmetry
-body parts that repeat the centre of the body
– sea anemone, sea stars, etc.
2. Bilateral Symmetry
-can divide the body into two equal halves- left
and right sides – usu have a front (anterior) and
back (posterior) ends and upper (dorsal) and
lower (ventral) sides.
• An anatomy with bilateral symmetry allows
for segmentation in which the is
constructed of many repeated and similar
parts or segments.
• Also animals with b.l. symmetry have
external body parts that repeat on either
side of the body – arms, legs, etc.
Cephalization
• Is the concentration of sense organs and nerve
cells at the front end of the body.
• Increased cephalization – animals can respond
to their environment quickly.
• Move with anterior end forward, so this end
comes into contact with new parts of the
environment first.
Body Cavity Formation
• Fluid filled space that lies between the
digestive tract and the body wall.
• 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.
• Also allow for specialized regions to develop