Chapter 1
UNIT 1:
ZOOLOGY Zoology is the study of animal kingdom, therefore is part of biology.
The study of zoology including structure, embryology, classification, evaluation, habits and distribution of animals both living and extinct. Zoo means where live animals are exhibited.
ANIMAL KINGDOM
When we said animal kingdom, this means we are discussing about the whole classes of animals in the world.
(1) They are multi-cellular organisms (meaning that they are made up of more than cell; many cells posses).
(2) They are Eukaryote organisms (means they contain nucleus).
(3) They do not contain cell walls
(4) They possess cell membrane
(5) Chlorophyll is absent
(6) They can not manufacture their own food (they can not possess their own food except depending on plants).
(7) They take in food through digestive process.
On Animal kingdom which known as Kingdom Animalia therefore we have two (2) Division of Animals (i) Invertebrates Animals and (ii) Vertebrates Animals.
VERTEBRATES ANIMALS; these are animals that posses backbone or pre-backbone and can be called Notochords, invertebrates are divided into five classes. Namely;
i) Pisces (Fishes)
ii) Amphibians
iii) Reptiles (Reptilia)
iv) Birds (Aves)
v) Mammals (Mammalian)
CHARACTERISTICS OF VERTEBRATE ANIMALS
(1) They are bilaterally symmetrical.
(2) They have single hollow nerve chord
(3) There is a closed blood systems.
(1) They are bilaterally symmetrical.
(2) They have single hollow nerve chord
(3) There is a closed blood systems.
(4) Body divided into head, trunk and tail.
(5) Two pairs of limb-pectoral and pelvic.
(6) At one stage or the other, possess gill slits.
(7) Their skins IS covered with scales, hairs or feathers.
(7) Their skins IS covered with scales, hairs or feathers.
(8) Presence of jointed endoskeleton that are made up of bones or cartilage.
(9) developed and controlled nervous systems with brain and spinal cord
(10) Triploblastic.
(1) FISHES
- They dwell in water PISCES (FISHES)
- their bodies are streamlined
- They respire with the aid of gills
- Movement is made possible by fins
- The presence of lateral line helps to detect vibrations
- They possess homodont dentition
- They are poikilothermic; meaning cold blooded
- They reproduce by laying eggs (oviparous)
- They have 2 chambered heart
- Reproduce sexually with external fertilization
- Possess swim bladder for buoyancy in water
Main examples of class Fishes are Cartilaginous Fish ( Dog fish, Sharks, and Rays) and Bony Fish (Tilapia, eel, and cat fish).
Check the following table drop down is a differences between Cartilaginous Fishes and Bony Fishes
Cartilaginous Fish
Bony Fishes
Differences Between Cartilaginous Fishes And Bony Fishes
Cartilaginous Fish
1) Males possess claspers
2) Scales are placoid
3) Mouth is ventral
4) Gills are of separate cleft
5) Skeleton is cartilaginous
6) Tail is heterocereal
7) Swim bladder is absent
8) Have 5-7 pairs of gills
9) Operculum is not present
Bony Fishes
1) Claspers absent in males
2) Scales are cycloid
3) Mouth is apical
4) Gills are in common left
5) Skeleton are bony
6) Tail is homocereal
7) Swim bladder is often present
8) Have pairs of gills
9) Operculum is absent
We will meet at the next lecture note from unit2 for the continuation of the lectures on the remaining clases which include; Amphibians, Reptiles, Mammals And Birds.
BY LEARN BIOLOGY
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