LESSON FOUR
KINGDOMS CONT...
Kingdom Animalia
- They are multicellular organisms.
- They are eucaryotes.
- They do not have cell walls, instead, they possesses cell membrane.
- They are divided into invertebrates and vertebrates.
Invertebrates
There are over 20 different phyla in invertebrates, few are discussed below:
Phylum Porifera
- They are simple aquatic animals.
- They are attached to rocks or shells.
- They live in colonies.They have a vase-shaped bodies with an internal cavity and a single opening at the top.
- They are mostly hermaphrodites (having both male and female reproductive ororgans).
- They reproduce both sexually and asexually.
Example: Sponge.
Phylum Coelentrata
They are multicellular aquatic organisms.They Possess cylindrical and radially symmetrical bodies.They have only one opening.They possess tentacles which contains stinging cells with which they paralyse their prays and is also used in picking food.
Examples: Hydra, Jelly Fish, etc.
Phylum Platyhelminthes
- They are small, flat and acoelomates (having no body cavity).
- They also possess only one opening.
- They are bilaterally symmetrical with definite head and tail.
- They possess excretory, nervous and reproductive systems.
- They may be free-living or parasitic.
- They are mostly hermaphrodite.
Examples: Tapeworm, Planaria, Liverflukes etc.
Phylum Nematoda
- They possess cylindrical elongated bodies pointed at both ends.
- They are acoelomates.
- They possess similar bodies.
- They possess two openings (mouth and the anus).They reproduce sexually.
- They are mostly parasitic.
- They possess well developed circulatory, digestive, excretory, and reproductive systems.
Examples: Thread worm, Guinea worm, Hook worm etc.
Phylum Annelida
- They possess cylindrical and elongated bodies.
- They possess segmented bodies of similar compartments each segment is called Septa.
- Each segment has a pair of excretory organs called Nephridia.
- They possess two openings.
- They are mostly aquatic.
- They reproduce sexually and may be hermaphroditic.
Example: Earthworm.
Phylum Molluscs
- They are mostly marine animals, and few on freshwater or land.
- They posses soft, non segmented bodies with muscular foot which may be adopted for crawling, burrowing or swimming.
- Some have their bodies covered with calcerous shells.
- They possess eyes and tentacles for sensitivity.
- Their bodies is covered by a soft tissue called Mantle.
- They carryout gaseous exchange using gills or lung in the mantle cavity.
- They reproduce sexually.
Examples: Snail, Slug, Octopus etc.
Phylum Arthropoda
- It is the largest phylum in the animal kingdom.
- They possess segmented bodies covered within an exoskeleton made of chitin.
- Their bodies is divided into head, thorax and abdomen.
- They posses joined appendages which may be used for feeding, movement and reproduction.
- They posses a pair of antannae for sensitivity.
- They undergoes shading of exoskeleton known as Ecdysis which allows their bodies to increase in size.
- They are divided into number of classes which are Insecta, Crustaceans, Arachnid and Myriapoda.
Class Insecta
- They constitute about 70% of all known species of animals.
- They are the only invertebrates that can fly.
- They possess a pair of antannae, compound eyes and simple eyes.
- They have a well-defined head, thorax and abdomen.
- They possess 3 pairs of walking legs.
- They respire by the use of Tracheae with Spiracles.
- They undergoes metamorphosis (series of changes of life cycle) which can be complete (as in butterfly and house fly) or incomplete (as in grasshopper).
- They are of great economic importance to humans.
Class Arachnida
- They possess two pairs of appendages for feeding and four pairs of walking legs.
- Their bodies is divided into cephalothorax and abdomen.
- Most of them possess fangs connected to a poisonous gland.
- They respire by means of trachea or book lungs.
Examples: Scorpion, Spider, Mite etc.
Class Myriapoda
- They are land animals found under rocks, logs or in the soil.
- They possess long segmented bodies.
- Some possess poisonous claws for attacking preys (eg Centipede), while others are harmless (eg Millipede which feed on decaying matter).
Examples: Centipede and Millipede.
Phylum Echinodermata
- They are slow moving marine animals living on the sea shores and seabeds.
- They possess spiny skinned bodies.
- They are triploblastic coelomates.
- Their larvae are segmented while adults are not.
- They have no specialised excretory organs.
- They possess tube feet for locomotion.
Examples: Sea cucumbers, Sea urchins, Starfish etc.
Vertebrates
- They are animals with backbone.
- They are bilaterally symmetrical.
- They Have a single hollow nerve cord.
- Their bodies is covered with hairs, scales or feathers.
- Their bodies is divided into head, trunk and tail.
- They possess two pairs of limb (pectoral and pelvic).
- They have well developed and controlled nervous system.
- They are triploblastic animals.
- They have closed blood system.
- They are divided into number of classes which are Mammalia, Pisces, Amphibians, Aves and Reptilia.
Class Aves
- They are homoiothermic (warm blooded).
- They are terrestrial (live on land) while others are arboreal (lives on tress).
- Their streamlined bodies and feathers are for flying.
- They possess scaly legs and breaks.
- They have hollow bones.
- They have good eyesight.
- They possess four chambered heart.
- Some are carnivorous (eg woodpecker) while others are omnivorous (eg domestic pigeon).
- They are oviparous with internal fertilization.
Examples: Domestic fowl, pigeon etc
Class Reptilia
- Most of them are terrestrial while few are aquatic.
- They are poikilothermic.
- They have homodont dentition.
- They respire using Lungs.
- Their bodies is covered with scales.
- They possess two pairs of leg, but absence in snakes.
- They are oviparous with internal fertilization.
- They show parental care.
- They possess incomplete developed four chambered heart.
- They are grouped into Lizards, Snakes, Crocodiles, and Turtles.
Class Amphibians
- They are believed to evolved from lobe-finned fishes.
- They possess moist skin.
- They are poikilothermic.
- They possess a long tongue which can be protruded and retracted quickly.
- At larval stage, they respire using gills, and at adult stage, using lungs, skin or mouth.
- They are oviparous with external fertilization.
- They possess three chambered heart.
- Some amphibians possess slender elongated bodies with neck and long tail.
- Most of them undergo metamorphosis.
Examples: Toads, Frogs, Salamander, Newts etc.
Class Pisces
- They dwell in water.
- They are poikilothermic.
- Their bodies is covered with scales.
- Their streamlined bodies and fins help in movement.
- They possess lateral line for detention of vibration.
- They possess homodont dentition.
- They are oviparous with internal fertilization.
- They respire using gills.
- They possess swim bladder for buoyancy.
- They possess two chambered heart.
Examples: Cartilaginous fish (eg Sharks, Rays etc), Bony fish (eg Tilapia).
Class Mammalia
- They possess mammary gland called Mammae with which they brest-feed their young ones.
- Their bodies is covered with hairs or furs.
- They are homoiothermic.
- Their bodies is divided into thoracic and abdominal cavity separated by a muscle sheath called Diaphragm.
- They possess external ear called Pinnae.
- They possess heterodont dentition.
- Their bodies contains sweat gland.
- They have well developed brain and a four chambered heart.
- They are viviparous.
- They respire using lungs.
Examples: Man, Cattle, Sheep, Bat etc.
Questions
- What is the structural difference between
- Annelids and Nematodes.
- Grasshopper and Cockroach.
- Toad and Frog.
- Centipede and Millipede.
- Spider and Scorpion.
- Monocotyledon and Dicotyledon.
- Pteridophye and Spermatophyte
- What is the leaf a fern called?
- Which class of animals in animal kingdom believed to have evolved from amphibians?
- Which class has the highest number of animals in animal kingdom?
- Why are bats classified as mammals?
