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Kingdom Animalia
The distinguishing characteristics of kingdom animalia
1. Animals are multicellular and each cell is bound by a plasma membrane.
3. Animals bodies are differentiated into tissues
4. Animals are heterotrophic.
5. Animals are capable of locomotion.
6. Animals have a nervous system
Possible angles or possible phyla (NECTA CSEE 2023)
1. Phylum Annelida
The word annelid is derived from a Latin word ‘’annelus’’ which means little ring. Thus members of this phylum are known as ringed or segmented worms. Annelida is a large phylum comprising of rag worms, lugworms, earthworms and leeches
The most common species is the earth worms
General features of annelids
1. They have a lip like extension on the first segment above the mouth called prostomium
2. Most annelids have chaetae. Chaetae is chitinous hair-like structures used for locomotion.
3. Some annelids have well developed metameric segments through the body
4. They have bilateral symmetrical bodies
5. Excretion takes place in convoluted tube-like structures called nephridia found in each segment
6. They have moist outer covering called cuticle vii. They reproduce by both asexually and sexually
7. They have closed circulatory system where by the blood flows
8. They have a central nervous system with paired cerebral ganglia in which paired commissures around the gut lead to a double ventral nerve cord
9. They arc eucoelomates meaning that their body cavities are lined by mesodermal tissues in both sides.
10. They have triploblastic bodies
Distinctive features of annelids
Features which distinguish annelids from other animals are as follows:
- Most annelids have hair-like structures called chaeta or setae made up of chitin.
- These are used for locomotion.
- They have perfect metameric segments throughout the body.
Structure of earthworm
1. An earthworm is an elongated, roughly cylindrical and metamerically segmented organism.
2. Each segment contains body systems such as circulatory, nervous, excretory and digestive systems. It has a complete digestive system that runs through the length of its body with both mouth and anus.
3. The circulatory system is simple and closed. The earthworm has a central and peripheral nervous systems.
4. Earthworms are hermaphrodite meaning that each individual has both male and female reproductive organs.
Advantages of annelids
1. Some annelids improve soil aeration through burrowing and mixing up of soil layers.
2. Earthworms play very important role in improving soil aeration.
3. Hence maintaining soil. Fertility.
4. They are used for commercial production of compost manure in the process known as vermicomposting.
5. Some annelids are used as a bait in the fishing industry Examples of annelids used as bait include earthworms and lugworms.
6. They are used as source of nutritious food for some fish and birds. They are rich in proteins and vitamins.
7. Some annelids are ecological decomposers. Hence, they contribute to nutrient circulation because they feed on decaying organic matter.
8. They remove pollutants from the soil and clean the environment by transforming organic wastes during feeding.
9. Faeces and urine of some annelids have considerable value as manure and increase soil fertility.
10. They are used as specimens in biological studies.
11. The excretory waste of some annelids which are in the form of cast increases sticking together of soil particles. This in turn increases water holding capacity of the soil.
Disadvantages or annelids
In some cases, annelids are harmful. The harmful effects of the annelids include the following:
1. Some annelids damage young roots of the growing plants.
2. Leeches are harmful to mammals, reptiles and fishes because they suck blood.
3. Earthworms can increase soil porosity and aeration which may cause water loss by seepage from the forms.
Advantages of earthworm in agriculture
1. Earthworms help in soil formation by barrowing process
2. They add nutrients when they decompose or giving out waste products from their bodies
3. They increase soil aeration. During the process of barrowing they increase soil porosity hence soil aeration
4. Their burrows help rainwater to drain through the soil more easily and prevent water logging.
5. They drag leaves and other plants part into the soil when they feed which adds humus content of the soil.
6. They are used by fishermen to trap fish during fishing
7. They improve water holding capacity of the soil
Habitat of earthworm
They live in moist soil
Mode of nutrition of earthworm They are heterotrophs (omnivorous)
Mode of reproduction of earthworm
They reproduce sexually by producing egg and sperm at the clitellum. Fertilization is external
Common name is Earthworm. Classification of earthworm to class level
| Organism | Kingdom | Phylum | class |
| Earthworm | Animalia | Annelida | Oligochaeta |
Phylum Arthropoda General features of arthropods
1. They have jointed and paired appendages that may be modified in various ways to form structures such as antennae, mouthparts, legs and reproductive organs.
2. They have segmented bodies which are organized into regions called tagmata. These regions are the head, thorax and abdomen
3. They have a coelom that is reduced and confined to cavities of excretory organs and reproductive duct. They also have another cavity called haemocoel which is formed during their development.
4. They have exoskeleton made up of chitin covering their body.
5. They have a ventral nervous system.
6. They have open circulatory system which is dorsally positioned.
7. Their body plan is bilaterally symmetrical.
8. They have compound or simple eyes.
Distinctive features of arthropods
1. They have jointed appendages which serve different purposes such as feeding, locomotion and sensation.
2. They have segmented bodies organized into regions called tagmata.
3. They have an exoskeleton which is made up of a chitin. The exoskeleton is usually stiff rigid or flexible.
Possible classes to appear in NECTA 2023.
- Class Arachnida
- Class Diplopoda
- Class Insecta
Class Arachnida
Arachnids are terrestrial arthropods consisting of animals whose bodies are divided into two regions; prosoma and opisthosoma. In some arachnids the two region are separated by a narrow waist like constriction.
The prosoma is partly or completely covered with a carapace like shield. Members of this class lack antennae and the majority are carnivores which feed on other invertebrates or small vertebrates.
Others arachnids such as ticks and some mites are ectoparasites which feeds on the blood of vertebrates.
Examples of arachnids are spiders, mites, ticks and scorpions.
Distinctive features of arachnids
Arachnids possess various unique features which distinguish them from other Arthropods. These features include:
1. They have no antennae, instead they have a pair of pedipulps which they use for defense and detection of stimuli.
2. They have four pairs of walking legs that arc attached to the cephalothorax.
3. They have only simple eyes used for vision while others are completely blind.
4. Gaseous exchange in arachnids is by means of book lungs or trachea.
5. They lack mandibles
Structure of the spider
Structurally the body of a spider is divided into two main parts called cephalothorax or prosoma and opisthosoma. They have six pairs of appendages which include four pairs of legs, chelicerae (mouthparts) and pedipalps.
On the ventral part of the abdomen, there are two hardened plates covering the book lungs. The spinnerets which extrudes silk arc also found in the abdomen. They possess very small eyes which are often clustered
Economic importance of arachnids
Arachnids are both advantageous and disadvantageous to human being and other organisms as follows;
Advantages of arachnids
1. Some arachnids such as mites play an important role in the formation of humus from decomposed leaf litter and wood.
2. Many arachnids are used as food by other animals. For example, spiders arc used as source of food by frogs, lizards and birds.
3. Spiders and other arachnids teed on wide range of pests thus helping to keep the population of pests under control.
4. Silk from spiders can be harvested for production of useful products such as surgical threads and bullet-proof vests.
5. They are used in biological studies and research.
Disadvantages of arachnids
1. Some arachnids such as scorpions can sting human beings and release their venom that cause severe pains. The bite from some spiders such as the black widow Latrodectus species can cause serious health problems in children and even death.
2. Some arachnids arc parasites to mammals and other vertebrates. Examples of such arachnids are ticks and mites which usually bite humans and other animals causing pain. They can also transmit diseases.
3. Some arachnids destroy crops and other properties. Examples of such arachnids are mites that attack food crops (on farm and in storage) and timber. Observable features of spider, and ticks i. Have four pair of legs ii. Have simple eyes iii. Body divided into two regions iv. Have poisonous sting
Adaptations of spider, and ticks
1. Have simple eyes for sight
2. Have poisonous sting for protection
3. Have legs for locomotion Habitat of spider and ticks
4. They are terrestrial organisms living in rocks, roof of the walls and in the soil
Classification of spider and ticks to class level
| Organism | Kingdom | Phylum | Class |
| Spider | Animalia | Arthropoda | Arachnida |
| Tick | Animalia | Arthropoda | Arachnida |
ii. Class Diplopoda Structure of a millipede
The body of millipede is elongated, cylindrical and segmented. The body consist of a series of segments whose number varies depending on the species.
The segments contain glands that secrete a noxious chemical to repel predators.
Each trunk segment hears two pairs of walking legs with exception of the segment behind the head.
Millipedes also have a head with one pair of antennae that help them to detect stimuli from the surroundings.
The head also has one pair of mouth parts that is found in from of the head.
Most millipedes have simple eyes located above the jaws. Such millipede have ability to see. However, some millipedes have no eyes at all, so that they cannot see.
Economic importance of diplopods
Diplopods are both advantageous and disadvantageous to both plants and animals including human being.
Advantages of diplopods
1. Most diplopods are used as source of food to other animals including birds, reptiles and amphibians.
2. They are also used in biological studies and research. Since diplopods feed on decaying plants and animal matter,
3. They help in the recycling of nutrients in the ecosystem.
Disadvantages of diplopods
1. Some herbivorous millipedes can cause damage to crops in the field.
2. Burrowing diplopods can cause some damage to the roots or germinating seeds.
Adaptation of millipede
1. They possess legs for locomotion
2. Presence of exoskeleton which protect them from external injury
3. They secrete a toxic fluid for protection from predators.
4. They live in soil and they are brown blackish in colour gives them camouflage.
5. Have one pair of antenna for sensation
Observable features of millipede
1. Have two pairs of legs in each segment
2. Have cylindrical body
3. Have one pair of antennae
4. Body divided in many segment
5. Have simple eyes
Habitat of millipede They lives in shady moist soils rich in organic matter
Common name is millipede. Classification of millipede to class level
| Organism | Kingdom | Phylum | Class |
| Millipede | Animalia | Arthropoda | Diplopoda |
iii. Class insecta
Members of class lnsecta are the most diverse and most abundant animals on the earth. They are found in all environments or habitats including freshwater, terrestrial and marine habitats.
Common features shared by members of the class Insecta
1. Their bodies are divided into three distinct parts: the head, thorax and abdomen.
2. They have three pairs of walking legs.
3. Their heads bear one pair of antennae. The antennae are used as sense organs for detection of odour molecules in the air, changes in the concentration of water vapour, sounds and for gauging air speed.
4. Most insects have one or two pairs of wings located on second and third thoracic segment.
5. They usually have three pairs of mouthparts which arc mandibles, maxillae, and fused labium. These parts are modified in different ways in order to suit various functions such as piercing, sucking, chewing and biting. This enables insects to feed on different diets.
Examples of organisms belonging to class lnsecta include grasshoppers, butterflies, houseflies.
Cockroaches, beetles, bees, ants, wasps and termites.
Distinctive features of insects
Insects differ from other arthropods in the following ways:
1. Their bodies are divided into three main regions or tagmata, namely the head, thorax and abdomen.
2. They have three pairs of jointed walking appendages.
3. They have a highly developed mechanism of gaseous exchange through trachea.
4. They have holes called spiracles located on the abdomen and joined lo the tracheal tubes which help to ensure efficient gaseous exchange
5. Majority have one or two pair of wings
6. Few lack wings for example fleas and lice.
Structure of a grasshopper
A typical example of an organism in the class Insect is a grasshopper. The body of a grasshopper is elongated and segmented. It is divided into a head, thorax and abdomen
The head of the grasshopper has a pair of antenna and compound eyes. Each compound eye is made up of thousands of tiny units closely packed together.
The head also consists of three pair of mouthparts namely mandibles, They have three pairs of legs
The body of the grasshopper is covered by a rigid exoskeleton
Economic importance of insects Advantages of insects
Insects are both advantageous and disadvantageous to humans and other organisms.
1. They are used for production of various substances. For example, honey bees produce honey, wax and bee venom silk worms produce silk that can be used for commercial purpose.
2. They are used in biological control of pests. Insects have been used effectively as predators to kill or control pests. For example, lady beetles are used to kill aphids. Aphids arc the insect pests that transmit viruses to plants.
3. Insects such as bees and butterflies arc useful in agriculture as they act as pollinators. Many plants depend on insects for pollination.
4. They are used in scientific research particularly in fields of physiology, genetics and evolution. The fruit flies (Drosophila melanogaster are among the insects used for this purpose.
5. Some insects are used in the production or medicine. Such insects include blister beetles that produce cantharidin which is used for treatment of urine genital diseases.
6. Many insects are used as food, they are a good source of proteins for human beings and other animals. Examples or such insects include winged termites, edible grasshoppers, locusts, and cockroaches, larvae of beetles, butterflies and moths.
7. Some insects are scavengers and feed on rotten or decayed materials hence helping in reducing rubbish and ensuring nutrient recycling in the ecosystem. Examples or such insects arc cockroaches.
8. Some insects improve aeration and soil fertility. For example, termites breakdown plant tissues thus improving soil facility
Disadvantages of insects
1. Some insects such as wasps and bees can cause painful bites and stings. Stinging insects that live in colonies can cause significant injury and even death.
2. Some insects are vectors of animal and plant diseases. For example, mosquitoes carry Plasmodium spp. which cause malaria. Tsetse flies carry Trypanosoma spp. a parasite which cause sleeping sickness to human beings. In addition, white flies carry tomato yellow leaf curl virus which cause chlorosis in plants.
3. Some insects destroy trees and crops. Examples of such insects include locusts and the caterpillars.
4. Some insects are ectoparasites of mammals. For examples jiggers and bedbugs which tend to suck blood from their hosts.
5. Some insects destroy human properties. Example cockroaches which spoil food. termites, beetle and carpenter bee that cat wooden furniture and moth larvae that feed on carpets and clothes.
Observable features of Housefly, Cockroach, Beetle,
Butterfly and Grasshopper
- Have one pair of antennae
- Have jointed legs
- Have pair of wings
- Have compound eyes
- Body divided into three parts
Adaptations of Housefly, Cockroach, Beetle, Butterfly and Grasshopper
- Have antennae for sensation
- Have legs for locomotion
- Have wings for flying
- Have compound eyes for maximum sighting
- Have abdomen for reproduction and respiration
Organism | Kingdom | Phylum | Class |
| Housefly | Animalia | Arthropoda | Insecta |
| Cockroach | Animalia | Arthropoda | Insecta |
| Beetle | Animalia | Arthropoda | Insecta |
| Butterfly | Aniamalia | Arthropoda | Insecta |
3. Phylum Chordata
This phylum comprises of animals with a high degree of body organization.
Animals under this phylum possess a notochord during embryonic development that strengthens and supports the body.
In protochordates. The notochord persists throughout life, but in most vertebrates it is replaced by the vertebral column in adulthood.
General features of chordates
Chordates possess the following features:
1. They are triploblastic animals.
2. They are coelomate animals.
3. Their bodies are metamerically segmented and bilateral symmetry.
4. Some are homotherms while some are piokiotherms
5. Most chordates have a ventral heart. (l) Most chordates have a closed circulatory system.
6. Most have endoskeletons made up of bones and cartilages
7. Some chordates have central nervous system made up of the well-developed brain and a spinal cord.
8. They occupy both terrestrial and aquatic habitats.
9. Some chordates are viviparous in which their young develop inside the body while others are oviparous as their young develop outside the body
10. Most chordates have a complete digestive system with two openings, the mouth and anus.
11. Most chordates have segmented muscle blocks called myotomes, one muscle block on either side of the body.
Distinctive features of chordates
Chordates have unique features that differentiate them from other animals.
They have the following features at some stages of embryological development:
- A notochord.
- Pharyngeal pouches or gill slits.
- Post-anal tail.
- A dorsal hollow tubular nerve cord.
Possible classes (NECTA CSEE 2023)
- Osteichthyes(bony fish)
- Class amphibia
- Class reptilia
- Class mammalia
- Class aves
i. Class Osteichthyes
This class comprises of the bony fish. Their skeleton is made up of hard bones instead of cartilage.
Examples of bony fish include tuna, tilapia, Nile perch, herring, butterfly fish and catfish
Distinctive features of bony fish
The following features differentiate bony fish from other chordates:
1. They have four pairs of visceral clefts as their gill openings. These are covered by an operculum.
2. Most of bony fish have swim or air bladder which provides them buoyancy during swimming.
3. Most have a bony endoskeleton and their skin is covered by glands producing mucus that make them slippery.
4. Most have symmetrical or homocercal caudal fins. This means that their caudal fins can be divided into equal parts.
5. They have terminal mouth.
Structure of a Tilapia
Tilapia fish has a laterally flattened body that tapers at both ends.
lt has a streamlined body shape that enables it to overcome water resistance during swimming.
The surface of its body is covered with overlapping scales.
In addition, tilapia has a lateral line that runs along the side of its body. The lateral line is a series or sensory organs called neuromasts that help the fish to sense vibrations and water pressure.
Economic importance of bony fish
Most bony fish have both advantages and disadvantages to humans and other animals.
Advantages of bony fish
1. Most bony fish are rich in protein, hence, they are used as food to human and other animals.
2. They are also source of income to fishing communities. Industrially processed fish products such as bones can be transformed into usable goods such as chicken feed.
3. Oil produced from the fish are also useful as medicine. Some bony fish are used for ornamental purpose. Additionally some bony fish are used in biological studies and research.
Disadvantages of bony fish
1. Sting from some bony fish such as stonefish can cause pain, swelling, necrosis and even death.
2. Shocks from electric eels and electric catfish can cause injury or death due to drowning.
3. Also, some exotic bony fish when introduced into a new habitat can cause extinction of endemic fauna due to competition and predation.
Adaptations of tilapia
1. It has tail for swimming
5. Possess gills for gaseous exchange
2. It has pair of eyes and nostrils for sensitivity
3. Cycloid scales pointed backward to support movement during swimming
4. Possess swim bladder for buoyancy maintenance
Observable features of tilapia
- Has eyes, and terminal mouth
- Possess tail
- Has gills
- Has cycloid scales
- Has fins
Habitat of tilapia
They are living in water (aquatic organism) Mode of reproduction of tilapia fish Reproduce sexually by external fertilization
Classification of tilapia fish to class level
| Organism | Kingdom | Phylum | Class |
| Tilapia fish | Animalia | Chordata | Osteichthyes |
ii. Class amphibia
The term Amphibia comes from two Greek words "amphi" meaning "both" and "bios" which means "life". Therefore. Amphibia literally mean double life. This is due to the fact that amphibians live both in water and on land.
Most amphibians spend their life partly in aquatic environment and partly in terrestrial environment.
They have two pairs of pentadactyl limbs for locomotion except caecilians which are limbless.
The forelimbs of some amphibian have less musculature while the hind limbs of frogs and toads arc long with powerful muscles for jumping.
Distinctive features of amphibians
Amphibians have the following unique features that differentiate them from other chordates:
1. They have protruding eyes for wide visibility of prey.
2. Amphibian eggs have a jelly structure which is prone to dehydration when exposed to air.
3. During the larval stage amphibians use gills for gaseous exchange. In adult stage, amphibian use their skins when they are in water and lungs when they are on land.
4. They have moist skin and most occupy both water and land environments.
STRUCTURE OF A FROG AND A TOAD
Economic importance of amphibians
Amphibians have both advantages and disadvantages to humans and other organisms as follows:
Advantages of amphibians
1. Some amphibians arc source of food to humans and other organisms such as snakes and birds.
2. They are also used in biological studies and research. For example, frogs and toad are dissected in school laboratories to study various body systems.
3. Since they eat flies, they help in eliminating disease vectors such as houseflies.
4. In addition, some amphibians have unique features that attract researchers and tourists, hence act as the source of income. The Kihansi Spray Toad (Nectophrynoides asperginis) for example has unique biological feature of giving birth to live Youngs.
5. In the amazon basin, secretions from some amphibians are used by natives to produce toxin darts used for hunting purpose.
Disadvantages of amphibians
1. During breeding period, some amphibians such as male frogs and toads make loud noise thus annoying people living in that environment.
2. They also contribute to water pollution by laying their eggs on the surface of water. Some frogs, toads and newts produce toxins which cause skin irritation and severe symptoms if ingested Toxins from cane toads can cause seizures, cardiac effects and even death.
Habitat of the frog
They are found normally in damp situations on grass near water, damp ditches and swimming in ponds or streams.
Common name is frog.
Scientific name of frog is Rana temporaria.
Mode of reproduction of frog
They reproduce sexually by external fertilization
Class reptilia
Reptiles are among a diverse group of egg-laying vertebrates. Their bodies are covered with scales or scutes, Reptiles include animals such as crocodiles, alligators, chameleons, tortoises, snakes and lizards.
They undergo internal fertilization and their fertilized yolky eggs are laid on land. However, some reptiles such as snakes
are oviparous. This means they lay eggs which remains in the mothers’ body until they are ready to hatch.
Reptiles are found in diverse habitats such as deserts, mountains, rocks, tree tops and in water. They are mostly terrestrial with few aquatic members such as crocodiles, turtles and terrapins.
They are ectothermic (poikilotherms) vertebrates, implying that their body temperature fluctuates according to the change in environmental temperature. Most reptiles have two pairs of pentadactyl limbs.
Some members such us snakes and some lizards are limbless.
Distinctive features of reptiles
Reptiles possess the following distinctive features:
1. They have dry skin covered with horny scales or scutes.
2. Their eyes are located at the front part of the head to facilitate binocular vision. Some reptiles can move each eye independently. This helps to increase their visibility hence locating their food and escaping from predators.
3. They lay soil shelled eggs called amniotic eggs which protect the embryo from drying out. The eggs have yolk which nourishes the embryo and enables it to develop outside the water environment.
4. All reptiles have a three-chambered heart except crocodiles which have a four-chambered heart.
5. Most have clawed feet.
Structure of lizards
A lizard is a typical example of a reptile. The body of a lizard is divided into three parts namely head, trunk and tail. Lizards have a dry scaly skin, external ear openings and most of them have clawed feet.
They also possess two pair of legs. In most species the tail is fragile and easily broken but regenerates later. They have shortened legs which help them in walking, but other lizards such as Delma species are legless.
They also possess eyes with movable eyelids. The two eyes can move independently, thus helping lizards to find food and escape from predators.
Economic importance of reptiles
Reptiles are both advantageous and disadvantageous to humans and other organisms as follows:
Advantages of reptiles
1. Reptiles are used by other animals as source of food. For example, birds eat reptiles such as snakes, lizards and chameleons. Some reptiles such as crocodiles, turtles and snakes are a source of human food in some communities.
2. Some reptiles also provide valuable skin used in making different products. For example, the crocodile skin is used in making belts, shoes and handbags.
3. Since reptiles eat small insects they help to reduce harmful insects in the environment or ecosystem. For example, lizards feed on mosquitoes and cockroaches, hence reduce their population in the environment.
4. Furthermore, some reptiles or their products are used for ornamental purposes. For example, tortoises are used for decoration in homes.
5. Tortoise shells are used to make combs, ornaments and traditional
Disadvantages of reptiles
1. Some reptiles such as crocodiles can attack livestock and humans causing serious injuries or death.
2. A bite from venomous snakes can also cause serious health problems or death to humans and other organisms.
Class Mammalia
The study of mammals is called mammalogy
Mammalia contains a small number of species but it is probably more successful than other animals
There are terrestrial, aquatic, and aerial mammals; oviparous, ovoviviparous and viviparous mammals.
General characteristics of mammals
1. Body covered with hair.
2. They have integument with sweat, scent, sebaceous, and mammary glands.
3. They have skull with two occipital condyles and secondary bony palate; middle ear with three ossicles (malleus, incus, stapes).
4. They have seven cervical vertebrae; pelvic bones fused
5. They have mouth with diphyodont teeth (milk, or deciduous, teeth replaced by a permanent set); teeth heterodont in most (varying in structure and function)
6. They have movable eyelids and fleshy external ears (pinnae).
7. They have circulatory system of a four chambered heart
8. They have respiratory system of lungs with alveoli
9. They have muscular diaphragm which separates thoracic and abdominal cavities
10 . The brain highly developed, especially cerebrum
11. They are endothermic
12. They have separate sexes; reproductive organs of a penis, testes (usually in a scrotum),ovaries, oviducts and vagina
13. They undergo Internal fertilization; eggs develop in a uterus with placental attachment
14. The young are nourished by milk from mammary glands
Common name Rat
Classification of the rat to class level
| Organism | Kingdom | Phylum | Class |
| Rat | Animalia | Chordata | Mammalia |
v. Class aves
The study of birds is called ornithology
Birds are traditionally classified as members of the class Aves (from Latin word avis = bird).
The single unique feature of birds is possession of feathers. No other living vertebrate group has feathers
Characteristics of bird
1. Body spindle shaped, with four divisions: head, neck, trunk, and tail
2. Neck is long for balancing and food gathering.
3. They have four limbs but the forelimbs modified for flying
4. They have circulatory system of 4-chambered heart.
5. They are endothermic (Homoeothermic).
6. Gaseous exchange is by lungs, with thin air sacs
7. Excretory system of metanephric kidney; ureters open into cloaca; no bladder; semisolid urine;
8. Uric acid is the main nitrogenous waste.
9. Sexes are separate; testes paired, with the vas deferens opening into the cloaca; females with functional left ovary and oviduct only, copulatory organ (penis) is present only in few birds e.g. ducks, geese, and paleognathids.
10. Fertilization is internal
The similarities between birds and reptiles
1. Both have scales creates a waterproof barrier that helps prevent dehydration in dry air
2. Both lay eggs – shelled eggs on land (amniotes)
The differences between birds and reptiles
1. Birds have feathers, reptiles do not have feathers.
2. Birds have wings allowing them to fly while reptiles have lack wings
3. Reptiles are cold blooded or ectothermic; while birds are warm blooded or endothermic.
4. Birds have hollow bones making them lighter & able to fly while reptiles have solid, dense bones.
Adaptations of birds for flight
1. They have feathers which are used for flight
3. They have no teeth, urinary bladder, no penis in most birds and have only one ovary of which all of them help to reduce body weight
4. They have pneumatic (air filled) bones which help to reduce body weight
5. They have enlarged sternum where the flight muscles are attached
6. The have long neck for balance
7. They have stream lined body to reduce air resistance
Possible angle NECTA 2023 QUILL FEATHER
Possible questions on the quill feather
1. Describe the basic anatomy and structure of a quill feather
Answer: Quill feathers, also known as flight feathers, have a rigid central shaft or quill made of keratin. They feature a tapered shape with a vane on either side of the quill.
The vane is composed of barbs, which further branch into smaller structures called barbules. Interlocking barbules give the feather its shape and function.
1. What is the primary function of quill feathers in birds?
Answer: The primary function of quill feathers, also known as flight feathers, in birds is to enable flight.
Explain how quill feathers contribute to a bird's ability to fly.
Answer: These feathers are essential for a bird's ability to achieve and maintain flight.
They play a fundamental role in providing lift and thrust during wing movement, allowing birds to navigate through the air.
1. How do quill feathers aid in thermoregulation (temperature control) in birds?
Answer: Here is how quill feathers help in thermoregulation:
1. Insulation: Quill feathers, especially contour feathers, have a fluffy and insulating structure. They trap a layer of air close to the bird's body. This trapped air serves as an effective insulator, reducing heat loss from the bird's warm body to the colder external environment.
2. Regulating Body Temperature: Birds are warm-blooded animals, meaning they can maintain a relatively constant body temperature even in varying environmental conditions.
Quill feathers assist in this process by minimizing heat exchange between the bird's body and the surrounding air. In cold weather, they help retain body heat, while in hot weather, they can prevent excessive heat absorption.
3. Regional Adaptations: Birds living in extreme environments have specific adaptations related to their feathers. For example, in cold climates, some species have specialized down feathers close to their bodies for maximum insulation. In desert environments, birds may have fewer or thinner contour feathers to reduce insulation and avoid overheating.
4. Discuss any adaptations or variations in quill feathers among different bird species.
5. How do waterfowl, such as ducks and swans, utilize specialized quill feathers for buoyancy and waterproofing?