topic 4

Question 1

what are General characteristics of animals

Answer 1

1.Ingest their food (heterotrophic)
2. Lack cell walls
3. Most have muscle and nerve cells
4. Most reproduce sexually
5. Development is governed by a unique
conserved genetic network (Hox genes)

Question 2

what phylum does sponges belong to

Answer 2

Phylum Porifera

Question 3

characteristics of sponges

Answer 3

Mostly marine; a few
freshwater
Mostly colonial
Sessile adults
Asymmetrical
Cellular level of organization
No true muscles, nerves, or
Hox genes

Question 4

Animal body plans

Answer 4

1. Radial or bilateral symmetry
2. Body tissue organisation
3. Body cavities
4. Protostome or Deuterostome

Question 5

stages of Early embryonic development in animals

Answer 5

Blastula is hollow. Cavity is
called the blastocoel.
One side folds inwards forming
a pocket called the archenteron.
Opening is called the blastopore which
becomes either the mouth or anus.

Question 6

Gastrulation can lead to two

or three germ layers. what are they and describe each

Answer 6

Ectoderm — outer layer of skin (epidermis), scales,
feathers, and/or hair. In most animals, the ectoderm also
forms the nervous system.
Endoderm — inner layer, produces the lining of the
digestive tract and the respiratory system.
Mesoderm — middle layer, gives rise to the majority of
the organs as well as the skeleton, the muscles, the
circulatory system, and the dermis of the skin.

Question 7

characteristic of Phylum Annelida

Answer 7

Fluid-filled coelom

acts as a hydrostatic skeleton

Question 8

what is Protostomes

Answer 8

mouth develops at or near blastopore, and anus at
opposite end. Majority of bilaterian phyla
(e.g. arthropods, annelids,
flatworms)

Question 9

Deuterostomes

Answer 9

anus develops at or near blastopore, and mouth at

opposite end. Fewer phyla, but includes chordates (e.g.,vertebrates)

Question 10

how does marine animals reproduce

Answer 10

produce larvae. Larvae are independent, morphologically
different stages that develop from fertilised
eggs and must undergo a profound
change before assuming adult features.