Question

1. State five characteristics that define an animal.
2. State five “body plan” features that are used to characterize animals.
3. Name the nine major animal phyla and the most general description of each.
4. Which phylum is the most successful group of animals? What three characteristics attribute to their success?
5. Which phylum do humans belong to? What features distinguish this phylum?

Answer 1

•The five characteristics that define kingdom animalia are-

They are eukaryotic

They are heterotrophic

They are multicellular

Their cell doesn't have cell wall

Food if stored is in the form of glycogen or fat.

• Five body plans are:-

1 cell aggregate. - cells are loosely arranged. Eg. Spnoges

2 Blind sac body plan- body has one opening only. Eg. Coelentrates

3 Tube within tube - Body consists of two openings. It can be divided into two groups

a Protostomes - Mouth develops first. Eg. Flatworm, roundworm, mollusca, arthropoda

b deutrestomes- ani( posterior opening , known as rectum on humans) develops first. Eg. Echinodermata, non chordata, chordata.

• The nine phylum are-

1 Porifera - Mostly salt water, do not have any muscle or nerve system . Body consists of many pores known as ostia and osculum. Eg. Sycon, spongilla

2 Coelentrata- They have specialised stinging cells know as nematocyte. Body opening is surrounded by tentacles . They have two body from poly and Medusa .Eg. Hydra, Aurelia (jelly fish)

3 Platyhelminthis - Their body is Dorso ventrally flat. Most of them are parasitic, few free living. Eg. Taenia, Fasciola

4 Aschehelminthis- They are also known as Nematoda . Their body is cylindrical. Mostly parasitic . Eg. Ascaris, Wucheria

5 Annelida - Their body cavity is divided externally into many parts so they give ring like appearance. They are triploblastic . Eg- Earthworm and leeches

6 Arthropoda- They have jointed legs. Their body is divide into head, thorax and abdomen. They also have pair of compound eyes. Eg. Spider, butterfly ,mosquito and crabs.

7 Mollusca - Their body doesn't show segmentation. Their body is divide into anterior head, ventral muscular foot and dorsal visceral mass. Mostly aquatic . Eg-octopus, snail.

8 Echinodermata - They have spiny skin, hard exoskeleton made up of calcium carbonate. They show both bilateral and radial symmetry. Eg. Star fish, sea cucumber, sea urchin

9 Chordata - They have notochord, dorsal never chord. Pharyngeal gill slits. They have many classes - Pisces, aves , mammalia.

• Phylum chordata is the most successful group of animals .

• The three characteristics attribute to their success are -

They have proper digestive system, circulatory system etc.

Dorsal hollow nerve chord is present. Brain is also developed

They have internal skeletol

• Humans belong to phylum chordata , sub phylum vertebrata, class mammalia.

They have a well developed vertebral column , developed circulatory system, excretory system, internal skeletol system also present. These are  the most distinguishing feature of this phylum.

Class mammalia's most distinguishing feature is presence of well developed mammary gland in females .