METAMORPHOSIS IN INSECTS AND OTHER ANIMALS



COMPLETE AND INCOMPLETE METAMORPHOSIS IN ORGANISMS

METAMORPHOSIS IN INSECTS AND OTHER ANIMALS
Describe reproduction in:
Cockroach is an example of biting and chewing insect
Housefly
Snail
Differentiate between complete and incomplete metamorphosis.


WHAT IS METAMORPHOSIS

Metamorphosis is defined as the series of gradual changes of formed and shape of an insect from the fertilized egg (immature stage) to adult (mature stage of adulthood).






Certain organisms when they are hatched from eggs do not exactly resemble the adult form. They therefore undergo series of changes in shape or form until the adult stage is reached. This process is what is called metamorphosis.


TYPES OF METAMORPHOSIS

There are two types of metamorphosis. These are complete and incomplete metamorphosis.

Complete metamorphosis

Complete metamorphosis is the series of gradual changes which take place in insect from fertilized eggs to lava, then to pupa and finally to the adult stage.
Complete metamorphosis involves four stages. Which are: eggs==larva==pupa==adult
Examples of insects which exhibit complete metamorphosis include housefly, mosquito, butterfly, bees, wasps and beetles
these are also examples of piercing and sucking insects


Incomplete metamorphosis

Incomplete metamorphosis is defined as the series of gradual changes in insects which take place from fertilized eggs to nymph and finally to the adult stage. Incomplete metamorphosis involves only three stages. They are: egg=nymph==adult.
Examples of insects which exhibit incomplete metamorphosis include: grasshopper, cockroach, dragonfly, locust, aphids, termites and praying mantis.


Differences between complete and incomplete metamorphosis

COMPLETE METAMORPHOSIS
1. Four stages of development are involved.
2. There is presence of pupa (resting stage)
3. There is no resemblance between pupa and adult
4. There is absence of nymph
5. Examples of complete metamorphosis are housefly and mosquito-also causes malaria.








STAGES OF INCOMPLETE METAMORPHOSIS

1. Three stages of development are involved
2. There is absence of pupa (no resting stage)
3. There is resemblance between nymph and adult.
4. Nymph is present
5. Examples of incomplete metamorphosis are cockroach and grasshopper.



INCOMPLETE METAMORPHOSIS IN COCKROACH

Life history of cockroach is an example of incomplete metamorphosis.
The cockroach exhibits incomplete metamorphosis. This starts from fertilized egg to nymph and finally to adult or imago stage i.e. Egg==Nymph==Adult
Mating begins when the male introduces spermatozoa into the posterior part of the female’s abdomen through the genital opening. These spermatozoa are then stored in spermatozoa pouch in the body of the female. From here, they meet the eggs as the latter pass towards the exterior. Fertilization is internal.
i. Egg stages in cockroach: the egg of the cockroach are laid in a horny egg case called ootheca (plural oothecae) formed in the body. This is a chitinous structure which looks like a purse. There are usually 10-15 eggs in one egg case and they are arranged in two rows of 5 to 8 eggs per row. The female cockroach carries this egg case for some time in its abdominal pouch. It then deposits it in a dark, warm and humid place.
ii. Nymph stage in cockroach: after some time (about 30-100 days) these eggs hatch out into very small, wingless, colourless nymphs. These nymphs feed and grow large and soon begin to moult. During these series of moulting, the wings appear, the nymptial life last for 10 to 16 months.
iii. Adult stage of cockroach: the appearance of the wings shows adulthood in the nymph. The adult cockroach now has wings, legs, abdomen, antenna etc. fully developed. The cockroach requires about 11 to 20 months to develop from egg to adult.


COMPLETE METAMORPHOSIS IN HOUSEFLY

Life history of the housefly is an example of complete metamorphosis
The housefly exhibits complete metamorphosis, i.e. Egg==Larva==Pupa==Adult.
The housefly breeds on any decomposing organic materials e.g. faeces, rotten meat etc.
Housefly has a short life cycle of about 3-4 weeks.


1.

Egg stage during metamorphosis:

the female housefly lays about 2-7 batches of eggs, each batch consisting of 100-150 eggs. The eggs which are white are laid in moist, rotten animal, and plant remains including human faeces. They hatch out in 8 hours to 3 days into white larvae called maggots.

2.

during metamorphosis Larva stage:

the body of the larva called maggots is made up of twelve segments. It is pointed at the anterior end which bears the head (on the first segment) but very broad at the posterior end. The head bears a pair of hook used for tearing food and to draw the maggot along. It has small mouth which lies between two oral lobes. On the ventral surface of each of the sixth to twelfth segment lies a small spiny pad which takes the place of the legs. The maggot has two pairs of spiracles used for breathing. They are located on the 2nd and on the 12th segments of the body. It moults or sheds its skin several times and last for about 5 to 14 days after which it moves to a dry place to begin the pupa stage


3.

Pupa stage during metamorphosis:

the maggot shortens, its skin becomes hard and brown and functioning as the pupa case or puparium. The pupa is an oval barrel-shaped object with rings running transversely around it. It does not feed or move. It is during this stage that internal reorganization of the body takes place.

Adult or Imago stage:

in about 3 to 10 days later, the young adult or imago hatches out from the puparium. It emerges from the puparium by using a sac-like organ attached to its head to break it open. This organ is called the ptilinum. It inflates this organ with blood and presses it against the front end of the puparium. The pressure forces the top part of the case to crack. The imago then moves to the surface of the rotten filth and flies away when its wings are dry.







4.

DIFFERENCES BETWEEN METAMORPHOSIS IN HOUSEFLY AND TOAD

HOUSEFLY
1. Takes place on land
2. Pupa or resting stage present
3. Takes shorter time

METAMORPHOSIS IN TOAD

1. Takes place in water
2. No pupa or resting stage
3. Takes longer time

REPRODUCTION IN SNAIL

Snails belongs to group called Molluscs. They reproduce sexually. The adult male possesses the male cells called spermatozoa while the female possess eggs. When the male mate with the female body leading to internal fertilization which involves the fusion of the spermatozoa and the eggs. The female later lays the eggs in a cool, dry land. After some days the egg hatches on their own and new baby snails emerge.read snail farming here


REPRODUCTION IN TOAD

In sexual reproduction, the male produces the spermatozoa while the female produces the egg or ovum. The fusion of the spermatozoa and the egg in the fallopian tube of the female during mating is called fertilization. The fusion of these sex cells, i.e. spermatozoa and egg results in the formation of zygote. The zygote undergoes cell division to form a developing organism called embryo.

STAGES IN THE DEVELOPMENT OF TOAD

1. Courtship stage: reproduction in toad usually takes place during the rainy season. The male makes loud croaking noise to attract the females which are usually swollen with eggs. The male toad later climbs on the female’s back and holds her firmly with the thick pads on its thumbs. As the female lays her eggs, the male releases its seminal fluid on them resulting in external fertilization.
2. The egg stage: the eggs laid are surrounded in strings of jelly. The jelly performs the following functions:
i. Protects the eggs from mechanical injury when water is disturbed.
ii. It separates the eggs to enable them receive adequate oxygen.
iii. Prevents bacterial and fungal attacks on the eggs.
iv. It prevents the eggs from drying up. The fertilized eggs (zygote) undergo cell division by mitosis process to form the embryo. The embryo feeds and grow around the egg yolk. Dissolved energy diffuses through the jelly into the embryo.
3. The young tadpole stage: the series of changes which takes place from the development of tadpoles inside the egg to adult stage is called metamorphosis. After 1 to 2 days, the young tadpole emerges from the jelly and grow. At this time, it attaches itself to a water weed by a sticky substance secreted by a V-shaped cement gland on the underside of the head. At this stage, the tadpole has no mouth and still feeds on the egg yolk. It obtains dissolved oxygen through the skin for respiration. Developing eyes, ears and nostrils are seen and a portion marked for the appearance of the mouth is equally noticed.
4. The external gill stage: the young tadpole now has a clear head, body and tail. It develops three external gills on either side of the head for respiration. It also develops horny jaws which are used to feed on water weeds. The intestine is long coiled. The V-shaped cement gland is still present in the tadpole.
5. Internal stage: about 6-10 days after hatching, the external gills disintegrate while the internal gills develop. A gill cover (operculum) grows over the gills leaving an opening called spout on the left side only through which water flows out of the gill chamber. The tadpole now breathes like a fish. During this stage, the tail elongates and muscles
then develop.
6. The limb stage: the hind limbs grow first and develop. The fore limbs then starts to grow out. The left fore limbs appears first through the opercula opening, followed by the right which disintegrates while the lungs start developing. The mouth develops and replaces the horny jaws. The intestine shortens, the tadpole starts eating small small animals in the water. The eyes become big and prominent.
7. Young toad stage: the tadpole changes into a small toad by reabsorbing the tail. It comes out of the water to the land where it grows into a full adult toad. It usually takes about 40-45 days for metamorphosis in toad to take place, i.e. from egg to adult toad.

Effect or Role of Hormone in the Development of Toad

In toad and other amphibians metamorphosis is controlled by the hormone called thyroxin. It is produced by thyroid gland in the region at the junction of the head and the trunk. For thyroxin to be made, there must be iodine in the water. The tadpole cannot change into adult form in the absence of this hormone. However, an increased level of thyroxine hastens metamorphosis.

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Important topics related to the above article

1. Recognizing living things
2. Biology as an enquiry in science
3. Branches of biology








4. Processes of methods of science
5. Usefulness of science
6. Living and non-living things
7. Characteristics of living things
8. Differences between plants and animals
9. Organization of life
10. Complexity of organization in higher organisms
11. Kingdom monera
12. Kingdom Protista
13. Kingdom fungi
14. Kingdom Plantae
15. Kingdom Animalia
16. Cell as a

The life cycle of liver-fluke and its economic importance




The life cycle of liver-fluke

What is liver fluke and The life cycle of liver-fluke
The liver-fluke is a flattened leaf-like endo-parasite. It is brown in colour and about 2cm long. The liver-fluke is an Endo-parasite of farm animals like cattle, sheep and
goat.
The primary host of the liver-fluke are farm animals while the Snail (Limnaea truncatula) is the secondary host.







THE LIFE CYCLE OF LIVER-FLUKE

Fertilized eggs of liver flukes are passed out together with faeces. During favourable conditions, the eggs hatch into ciliated larvae called miracidia. Each miracidium swims in water and is attracted to water snail which is the secondary host. It enters the body of the snail during which it loses its cilia and changes to a SPOROCYST and produces asexually to give rise to new larvae called REDIAE.


The REDIA of liverfluke

comes out of the SPOROCYST and goes to the digestive gland where it develops into a minute worm called CERCARIAE. The cercaria leaves the body of the snail and swim about in water until it finds a suitable host when animals come to drink dirty waters.
At times, the larvae may leave the host snail and encyst on vegetation. From there, they are ingested by grassing animals. The CERCARIAE penetrates the skin and tissues to enter the blood stream, and then to the liver tissue and finally to the bile duct where they firmly and finally settle down and develop into adult LIVER FLUKE
HERE IS A DIAGRAM OF THE LIFE CYCLE OF LIVER FLUKE


What are the economic importance of LIVER FLUKE?

The economic importance of liver fluke are as follows
1. Liver fluke causes a disease called BILHARZIA OR SCHISTOSOMIASIS.
2. Liver fluke affects the digestion of food of animals
3. The excretory products of liver fluke have a poisoning effect on the sheep
4. The liver fluke also results in liver rot, leading to drowsiness and death








How to control liver the spread of liver fluke

Liver fluke can be control in the following ways
1. Drain pasture properly since wet pasture can harbouir snail
2. Introduce ducks and geese to eat up the snails
3. Use lime on pasture because the eggs of liver fluke do not hatch in water containing high level of alkaline.


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Important topics related to the above article
1. Recognizing living things
2. Biology as an enquiry in science
18. Structures of plants and animal cells and functions of their components
19. Similarity and differences between plant and animal cell
20. Diffusion
21. Osmosis
22. Plasmolysis
23. Haemolysis
24. Turgidity
25. Faccidity
26. Nutrition
27. Feeding
28. Cellular respiration
29. Excretion
30. Growth
31. Cell reaction to its environment
types vertebrae and the vertebral column
32. Movement and responses
33. Reproduction







DESERT HABITAT, ITS CHARACTERISTICS AND TYPES OF DESERT



WHAT IS ARID LAND OR DESERT HABITATS?

Arid land or desert refers to the area of very low rainfall and high evaporation rate. Arid lands are the driest habitats, receiving less than 25cm of annual rainfall.


TYPES OF ARID LAND

There are two major types of arid lands or desert. These are hot deserts and cold deserts.

1.

characteristics of Hot deserts:

hot deserts of the world are located on the western coasts of the continents within latitude 15o-30o North and South of the equator. Examples of hot deserts are Sahara desert (North Africa), Arabian desert and Kalahari deserts (South Africa), Great Australia desert (Australia) and Atacama deserts of South America.


2.

characteristics of Cold deserts:

cold deserts are located or found in the interiors of the continents around 45o-60o North and South of the equator. The deserts is found in interior of Eurasia, North America and in Patagonia (South America)






Characteristics of Arid Lands (hot deserts)

The major characteristics of arid lands (hot deserts) include the following:

1.

Scarcity of water:

rainfall in arid land is very low and it may occur in few occasions during a whole year and it is always below 25cm per anum.


2.

Hot temperatures:

the deserts temperature are usually very high especially during the day but very low at night.


3.

Presence of sandy soils:

the nature of soil in arid land is sandy or rocky as there is little or no vegetation to improve the soil.


4.

High sunshine:

the sunshine in arid land is very high since there is little vegetation to shield it rays.


5.

Predominance of strong winds:

strong winds are often associated with deserts since there is no vegetation cover to reduce the speed of winds.


6.

Poor vegetation:

the hot deserts have scanty vegetation. It has short and scanty grasses with little and scattered trees and shrubs.


7.

Low relative humidity:

the relative humidity of hot deserts is usually very low since the area is characterized by low rainfall, high temperature and scanty vegetation.


8.

Presence of drought resistant plants:

the hot desert is characterized by the presence of drought resistant (xerophytic) plant species such as thorny bushes, bulbous cacti, dwarf acacias, and oleander.



Distribution of organisms (plant species) in arid lands or hot deserts

Plant species commonly found in hot deserts include: drought resistant plants like thorny bushes, bulbous cacti, scattered dwarf acacia, wiring grasses, date palm, baobab trees and euphorbia spp.


Adaptive features of plants in arid lands



1.

Adaptive features of Cactus:

cactus is a leafless plant with prickles or thorns to reduce transpiration. It also has thick succulent stem and side branches to store water for long drought.


2.

Adaptive features of Acacia:

this is a drought resistant plant, it has deep roots which absorb underground water deep down in the soil.


3.

Adaptive features of Baobab tree:

the leaves are waxy, hairy or needle-shaped to help reduce the rate of transpiration.


4.

Adaptive features of Wiring grasses:

it has narrow and slender leaves which helps to reduce the rate of transpiration in the plant.


5.

Adaptive features of Oleander:

this plant has extremely deep roots which is able to absorb underground water deep down in the soil.


distribution of organisms (animal species) in arid lands








Animals commonly found in arid lands

include: camel, rodents (e.g. rats), lizards, snakes
, toads, zebras, desert tortoise, pocket mice, locusts, grasshoppers, ants, butterflies, moths and beetles.


Adaptive features of animals in arid lands


1.

Adaptive features of Camel:

a camel can drink a lot of water to sustain itself for several days and hence can withstand a wide range of body temperature up to 40oC during the day. It can also walk for several days without drinking water.


2.

Adaptive features of Kangaroo rat:

this animal remains in burrow during the day to avoid excessive heat thereby cutting evaporation from its body.


3.

Adaptive features of Lizards and snakes

these animals have scales which limit the rate of water loss from their body.


4.

Adaptive features of Locust:

it has water-proof bodies and impervious cuticles. It also produces dry waste products, e.g. uric acid and guanine to enable it conserve water.


Adaptive features of Food chain in arid land habitat

The food chain in arid land can be demonstrated by the following examples:
1. Plants==Desert rats==snakes
2. Plants==Locusts==Wasps==Lizards
3. Plants==Ants==Scorpions==Snakes


Factors affecting arid lands

The major abiotic factors affecting arid land are almost the same with that of grassland. These factors are temperature, rainfall, sunlight, wind, and low relative humidity.







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Important topics related to the above article

1. Recognizing living things

45. Modes of nutrition
46. Feeding mechanisms in holozoic organisms
maintenance of teeth gum
47. Mammalian teeth
48. Dentition
49. Digestive enzymes
50. Meaning of ecology
causes of germs and diseases in humans
51. Local biotic communities or biomes in Nigeria
52. Major biomes of the world
53. Population studies
54. Ecological factors


WHAT IS BLOOD? FUNCTIONS OF Blood AND BLOOD PROPERTIES


THE BLOOD

THE BLOOD AND WHAT IT IS MADE OF

Some of us have played either the football or netball. Occasionally, we have obtained some wounds or have seen someone wounded. Others have had accidents when they cut their hands with blade or knife. This is bad and should be avoided. But, where there is a cut what do you notice?
A red liquid comes out of the body. This red liquid is known as blood.
you can read about blood circulation here






After a few minutes what happens? The blood forms a red solid part and a watery part which looks yellowish in colour.

This watery part is called plasma.

The solid part contains two types of cells which is

BLOOD AND WHAT IT CONTAINS

Solid part (cells)
Contains:
i. Red blood corpuscles (cells)
ii. White blood corpuscles (cells)

Watery part (plasma)
Contains:
i. Salt (from food)
ii. Sugar (from food)
iii. Protein (from meat)
iv. Waste products, e.g. urea (from the body)

WHAT ARE THE BLOOD CORPUSCLES?

a. The red blood corpuscles: These are small rounded cells which appear red. They contain a substance called the haemoglobin. This haemoglobin likes oxygen. In the lungs, it takes up oxygen and is carried by the red blood corpuscles to all part of the body. In the body, oxygen is set free for the body to make use of.

The body has about 30,000,000 million red blood corpuscles

.
b. The white blood corpuscles: these cells, like soldiers, defend the body against some germs which cause diseases. They are bigger than the red blood corpuscles and can move about slowly in the blood. About 42,000 million white blood cells are found in the body.

FUNCTIONS OF THE BLOOD

The blood does a lot of work in the body
i. The blood carries digested food substances such as glucose (sugar) and amino-acid (proteins) from the intestines to all parts of the body where they are needed.
ii. The red blood corpuscles of the blood take oxygen from the lungs to other part of the body. The waste products such as urea and carbon dioxide are carried in the blood. Urea is removed from the body as urine while carbon dioxide is expelled when we breathe out.
iii. The white blood corpuscles fight and destroy germs in the body. They can also prevent them from entering the body especially at wounded areas.

HOW THE BLOOD MOVES ROUND THE BODY

Our body is like a small town. Just as water in the town travels to all houses through pipes, the blood in the body travels to all houses through pipes, the blood in the body travels to all parts through its own small pipes called the blood vessels. The vessels that carries pure blood are called arteries while those that carries impure blood are called veins. The smallest blood vessels are called capillaries.
In towns, water is pumped to houses at the power station. In the body, the power station from where blood is pumped to all parts of the body is called the heart.

THE HEART IS THE ORGAN THAT PUMPS BLOOD

The heart is found inside the chest. Touch the left side of your
chest with your hand. You will notice the beating of the heart. This beating continues throughout life. When it stops death occurs.
The heart is like a `top’ or cone. Its walls are very thick. The thick walls help to pump blood round the body.






the heart is divided into four chambers.

These are the left and right auricles and the left and right ventricles. The walls of the ventricles are thicker than those of auricles.
From the heart arise a number of blood vessels or pipes which bring in or take away blood during its journey round the body. The most important of these blood vessels are the aorta and the pulmonary artery. The aorta takes blood to all parts of the body while the pulmonary artery takes impure blood from the body into the lungs where it is purified. The heart has some valves which prevent blood from moving backwards.

BLOOD ROUND THE BODY

When the left ventricle contracts the pure blood is pumped from the ventricle into the aorta which takes it to all parts of the body such as the head, arms, intestines, kidneys and legs. From all these places blood which is now impure is brought back into right auricle of the heart.
From the right auricle the impure blood is pumped into the right ventricle from where it is pumped again into the lungs to obtain fresh oxygen.
Pure blood from the lungs returns to the left auricle of the heart. From the left auricle it passes into left ventricle for the journey round the body to start again.


Please share if you find our article good,Important topics related to the above article
1. Recognizing living things
2. Biology as an enquiry in science
3. Branches of biology
4. Processes of methods of science
5. Usefulness of science
6. Living and non-living things
7. Characteristics of living things
8. Differences between plants and animals
9. Organization of life
10. Complexity of organization in higher organisms

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You can read some of most interesting topics below
Agricultural biology topics
HERE YOU WILL FIND EVERY AVAILABLE TOPICS ABOUT AGRICULTURAL SCIENCE AND BIOLOGY. AND THE LINKS TO THEIR VARIOUS SOURCES.

1. DEVELOPMENT OF AGRICULTURE
2. IMPORTANCE OF AGRICULTURE
3. SUBSISTENCE AGRICULTURE
4. COMMERCIAL AGRICULTURE
5. PROBLEM OF AGRICULTURAL DEVELOPMENT
6. SOLUTIONS TO POOR AGRICULTURAL DEVELOPMENT
7. AGRICULTURAL LAWS AND REFORMS
8. ROLES OF GOVERNMENT IN AGRICULTURAL DEVELOPMENT

80. SANDY SOIL CLAY SOIL
LOAMY SOIL

83. SOIL TEXTURE
84. IDENTIFICATION OF SOIL TYPES THROUGH EXPERIMENTS
85. RETENTION OF WATER BY VARIOUS SOIL TYPES

FOREST HABITAT, TYPES OF FOREST, IMPORTANCE AND CHARACTERISTICS OF FOREST HABITAT



FOREST HABITAT

A forest (forestry) is an extensive community of plants dominated by tall trees. These trees are of different species and height. The distribution of forest is mainly determined by climate especially rainfall and temperature. The rain forest is the dominant forest in Nigeria.


CHARACTERISTICS OF THE RAIN FOREST

1.

presence of broad leaves :

most trees in rain forest usually possess broad leaves which enable the plants to receive abundant light and enhance transpiration.


2.

presence of buttress roots :

most trees because of their large sizes often have buttress roots to support their heavy weight and height.


3.

presence of tall trees:

the bulk of the trees in rain forest are tall. Some are even 40 metres and above in height.


4.

Existence of canopies:

the trees in the rain forest are shaped in such a way as to form canopies.

5.

Trees exist in layers or storeys:

the trees in rain forest are zoned or stratified in such a way that they are arranged in layers or canopies, i.e. upper layers, middle layers, and lower layers.







6.

presence of fallen leaves on ground :

the forest is characterized by the flooring of the ground with lots of leaves as litres which in turn increases the presence of manure .


7.

trees have thin bark:

most of the trees have thin bark to enhance gaseous exchange and transpiration.


8.

CHARACTERISTICS OF presence of epiphytes:

the rain forest is also characterized by the presence of climbers and epiphytes on the trees which possess aerial roots for moisture absorption and respiration.


CHARACTERISTICS OF STRATA IN THE FOREST

The rain forest vegetation have plants which are naturally arranged in layers, strata or storeys, there are about five storeys in the forest. These are:


characteristics of the upper layer of the forest:

the upper layer or storey is made up of the tallest trees of over 40 metres tall. These trees are called emergents. The crown of the emergents do not normally






1. touch each other. Examples of plants in this category are iroko, obeche, mahogany, African walnut, ebony etc.


2.

characteristics of the middle layer of the forest:

the second layer in the rain forest is made up of tall trees of about 16-40 metres tall. Their crown touches each other, thereby forming a continuous canopy below the emergents.


3.

characteristics of the lower layer of the forest:

this is the third layer which is made up of small trees, less than 16m tall. They also form a continuous canopy below the middle storey.


4.

characteristics of the shrub layer:

this layer is made up of small trees, 1-5 metres in height. These are essentially small trees collectively referred to as shrubs.


5.

characteristics of the ground layer or forest floor:

this contains wet and shade loving plants which grow on the floor of the forest. These plants hardly receive sunlight due to canopies formed by bigger plants. Most plants are bryophytes and they include mosses, liverwort, lichens and thin leaved ferns.


DISTRIBUTION OF PLANTS IN A FOREST HABITAT

Varieties of plants exist in the forest. Popular examples of forest trees are African walnut, mahogany (khaya ivorensis), teak (tectonia grandis), opepe (sarcocephalus), obeche (triplochiton), iroko (chlorophora), oil palm (elaeis guinensis), ferns, orchids, lianas, mosses, lichens, liverwort, fungi, and mistletoe.


Adaptive features of plants in a forest habitat

1. Iroko and mahogany: these plants have strong tap root system and buttress roots which aid anchorage and support for the weight of the plants.
2. African walnut: these plants have broad leaves which aid transpiration and photosynthesis.
3. Obeche: these plants have tap root system and large buttress roots for support as well as broad leaves to aid photosynthetic activities.
4. Orchid: these are epiphytes which have mechanisms for storing water and absorbing moisture from air while growing on tree branches.
5. Mistletoe: these are complete plant parasites capable of developing root system that can penetrate the stem of a plant and feed directly from manufactured food by placing their roots on the phloem vessels of the host plants.



Distribution of animals in a forest habitat

Most animals in the forest live on trees (i.e. they are aboreal animals). The animals include bats, monkeys, snakes, squirrels, birds, lizards
, tree frogs, and chameleons. Some animals like earthworm and beetles live in the soil while some live among the litter on the ground, e.g. millipedes, ants and snails.

adaptive features of animals in a forest habitat

1. Monkeys: monkeys have prehensile tails and long limbs for climbing trees and jumping from one tree branch to another.
2. Bats: bats have a way in which the fore limbs and the hind limbs are joined on each side of the body by a fold of skin to form wings used for flight.
3. Green snakes: these snakes have protective colouration on their skin which makes it difficult to be detected by their enemies. They also have slim elongated body with grasping scales for winding around tree branches.
4. Chameleon: it has prehensile tail and opposable digits for grasping. it also has protective colouration to camouflage or disguise itself from predators.
5. Apes: apes move in groups or herds to protect themselves from predators. They also have high sense of sight to detect enemies.
6. Earthworm and snails: they have water permeable cuticle which reduces water loss and prevent drying up.
7. Birds: birds have powerful wings used for flying.

general adaptive features of animals that climb rain forest trees

a. There is presence of prehensile tails
b. They have opposable digits e.g. monkeys
c. They possess sticky adhesive discs on fingers e.g. geckos
d. They possess grasping scales e.g. snakes
e. They have grasping pads e.g. tree frogs
f. They have long, sharp claws for climbing e.g. squirrels

importance of water to rain forest

1. It is essential for photosynthesis
2. It helps to maintain the body temperature of organisms
3. It is essential for plant turgidity/mechanical support
4. It helps in metabolism of organisms
5. It provides moisture necessary for microbial activity
6. It provides moisture necessary for burrowing animals
7. It is also essential for translocation and transpiration
8. It is also essential for movement and survival of aquatic animals
9. It is important for plant and animal growth or germination of seeds.


food chain in a forest habitat

The forest has numerous plants and animals which can easily form several food chains. Examples of food chains in a forest habitat are:
1. Green plants==grasshoppers==toads==hawks
2. Green plants==caterpillars==lizards==snakes
3. Green plants==monkeys==lions


factors affecting the forest

Climatic factors which affect the rain forest include: rainfall, temperature, wind, relative humidity, sunlight etc. Rainfall and temperature are dominant factors that affect the rain forest, read details here. High rainfall and temperature give rise to a luxuriant rain forest vegetation.

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Important topics related to the above article
1. Recognizing living things
2. Biology as an enquiry in science









HERE YOU WILL FIND EVERY AVAILABLE TOPIC ABOUT AGRICULTURAL SCIENCE AND BIOLOGY AND LINK TO THEIR VARIOUS SOURCES.
1. DEVELOPMENT OF AGRICULTURE
2. IMPORTANCE OF AGRICULTURE
3. SUBSISTENCE AGRICULTURE
4. COMMERCIAL AGRICULTURE

43. TEMPERATURE
44. RAINFALL
45. WIND
46. SUNLIGHT
47. SOLAR






48. BIOTIC FACTOR AND AGRICULTURAL PRODUCTION
49. PESTS
50. BIRDS
51. DISEASES
52. SOIL MICRO-ORGANISMS
53. SOIL PH
54. ROCK FORMATION

75. SOIL WATER
126. CROP ROTATION
133. FARM POWER AND MACHINERY
134. SOURCES OF FARM POWER
135. HUMAN SOURCE/a>
149.
PLOUGHS
142. FIELD MACHINES
157. PLANTERS
164. SIMPLE FARM TOOLS
165. AGRICULTURAL MECHANIZATION
166. THE CONCEPT OF MECHANIZATION

WHAT IS FOOD CHAIN, FOOD WEB, TROPHIC LEVEL AND THEIR USES?


WHAT IS FOOD CHAIN, FOOD WEB AND TROPHIC LEVEL?

WHAT IS FOOD CHAIN, FOOD WEB AND TROPHIC LEVEL

Food chain is defined as a feeding relationship involving the transfer of energy through food from producers to consumers. This is a linear feeding relationship; in which energy is transferred from producer/plants, through a series of organisms/trophic levels; in which each organism feeds on the preceding one, and provides food for succeeding one in the habitat.
During the process which occurs in food chain, food energy is transferred from one organism to another in a linear form. The arrows shows the direction in which the food is being transferred, even though most food chains begin with producers. There are few exemptions that start with dead plants or animals.
For example, humus==earthworm==domestic fowl==man






FOOD WEB

Food web is defined as a complex feeding relationship among organisms in the same environment with two or more inter-related food chains.
Food web contains two or more food chains and therefore more organisms than food chain. In nature, the interaction in feeding are more complicated because a single plant could be fed upon by more than one or two organisms. When a consumer feeds on different types of plants or animals in a food web, it has a better chance of survival in its ecosystem.
In the food web in the picture, there are four food chains in the terrestrial habitat. Example of a food web in an aquatic habitat is illustrated below.


DIFFERENCES BETWEEN FOOD CHAIN AND FOOD WEB

CHARACTERISTICS OF FOOD CHAIN

1. It is a linear feeding relationship.
2. It involves one food chain.
3. It involves fewer organisms.
4. Organisms have lesser chance of survival.

CHARACTERISTICS OF FOOD WEB

1. It is a complex feeding relationship.
2. It involves two or more food chains.
3. It involves many organisms.
4. Organisms have greater chance of survival.

CHARACTERISTICS OF TROPHIC LEVEL

Trophic level, also called feeding level, is defined as the feeding level or each stage in a food chain or food web. In other words, trophic level is the number of links by which food energy is transferred from producers to final consumers. For example, in a food chain like the one below, we can have these levels.






CHARACTERISTICS OF PYRAMID OF NUMBER

Pyramid of number refers to the number of individual organisms at each trophic level which decreases progressively from the first to the last trophic level in a food chain. Pyramid is a diagrammatic representation of food chain in which producers form the base and the carnivores form the apex.
In a food chain or food web, there are relative number of organisms at different trophic levels. Normally, the number of organisms decreases progressively from the first to the last trophic level. For example,
Grasses==Grasshoppers==Lizards==Hawks



The number of grasses eaten by grasshoppers is greater than the number of grasshoppers, while the number of grasshoppers eaten by lizards is greater than the number of lizards and finally the number of lizards eaten by hawks is greater than the number of hawks. From this explanation, one discovers that there is a progressive decrease in the number of organisms from the first to the last trophic level. The diagrammatic representation of this progressive decrease in the number of organisms along the food chain is called pyramid of number. read about biting and chewing insect here.
endo-parasite here
sucking and piercing insect here

CHARACTERISTICS OF PYRAMID OF ENERGY

Pyramid of energy is defined as the amount of energy present in the living organisms at the different trophic levels of a food chain. In other words, the pyramid of energy represents a progressive decrease in energy from the first trophic level in a food chain or web. read more about energy transfer in the ecosystem here
Just like the pyramid of number, the producers at the first trophic level contain most of the energy.

The primary consumers have lesser energy while the secondary or tertiary consumers have the least energy.
Just like the pyramid of numbers, the producers as in the grasses form the base of the pyramid while the tertiary consumers, e.g. hawks from the apex. Energy therefore decreases from the base of the pyramid to the apex.
don't forget to read my post on weeds and their botanical names here

PRINCIPLES GOVERNING TROPHIC LEVELS AND THE PYRAMIDS

1. Food chain starts with photosynthesis (producers) and ends with decay.
2. Shorter food chains are made more efficient than larger food chains in term of waste of energy.
3. Large population are characterized by more steps in food chain. This means that useful energy decreases so that little of it will be made available to the tertiary consumers.


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Important topics related to the above article
1. Recognizing living things
2. Biology as an enquiry in science
3. Branches of biology
4. Processes of methods of science

43. test for Food substances
44. Balanced diet and kwashiokor
food tests





45. Modes of nutrition
46. Feeding mechanisms in holozoic organisms
maintenance of teeth gum
47. Mammalian teeth
48. Dentition
49. Digestive enzymes
50. Meaning of ecology
causes of germs and diseases in humans
51. Local biotic communities or biomes in Nigeria
52. Major biomes of the world
53. Population studies
54. Ecological factors

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