CHARACTERISTICS OF LIVING THINGS

Classification is defined as the arrangement of living things into groups based on structural genetic and cellular organization.  This is called TAXANOMY.The system of classification of living things  used today is based on that introduced by Swedish naturalist named Carl Von Linne(1707-1778).His name was better known in Latin as Carolus Linnaeus.He published the classification of plant 1753 and that of animal in 1758.

Living things are first separated into large group called KINGDOM. The division of kingdom smaller group called PHYLA (PHYLUM). The term division rather than phylum is usually used for plant. Phyla are divided into smaller groups called CLASSES. Each class is further divided into ORDER. Orders are further divided into smaller unit called FAMILIES. Families are again divided into GENERA (genius). A genius is broken into SPECIES. A species is a population of related organism that can interbreed within themselves to produce a fertile offspring. Genius is a group of closely related species. A family is a group of genera. An Order is a group of related families. A class is a group of related order. A phylum is a group of related classes. A kingdom is a group of related phyla.

Kingdom

 

 

Phylum or Division

 

 

Class

 

 

Order

 

 

Family

 

 

Genius

 

 

Species

Living things according to modern classification system which is based on physiology, biochemistry and embryology are classified into five kingdoms; MONERA, PROTOCTISTA, FUNGI, PLANTAE AND ANIMALIA.

MONERA (Characteristics)

They lack organized DNA i.e. the Deoxyribonucleic acid (DNA) is scattered in the cytoplasm an not in nucleus hence they are called prokaryotes.

  1. They have no mitochondrion in their cytoplasm

iii.        Their cell wall lack cellulose, their cell wall is made up of protein and fatty materials

  1. They are microscopic single called organism
  2. Some are motile while some are non-motile
  3. They feed both auto tropically and heterotrophic ally. Blue green bacterium & blue green algae

vii.       The reproduce only by asexual mean.

KINGDOM PROTOCYISTA (Characteristics)

  1. They have well organized DNA in the nucleus bounded by nuclear membrane hence they are called eukaryotes
  2. They are single called organism or unicellular organism

iii.        Some are motile while some are non-motile

  1. They live in water, damp soil, leaf litter and other terrestrial habitats that have sufficient moist.
  2. All protists use mitochondrion for cellular respiration
  3. They form cyst to survive adverse condition

vii.       They all reproduce both sexually and asexually Examples are Amoeba, Euglena, Chlamydomonas, Plasmodium.

Example of Monera are:  bacteria and photosynthetic blue green bacterium also known as blue green algae.

KINGDOM FUNGI (Characteristics)

  1. They all feed heterotrophic ally because they lack chlorophyll therefore cannot photosynthesize.
  2. They are simple multicellular organism that grow like plant but are not plant because they are not green in colour.

iii.        Their bodies are not divided into true root, stem and leaves

  1. They are mostly non-motile organisms composed of thread-like multinucleate hyphae collectively known as mycelium
  2. They reproduce by means of spores. Spores are unicellular microscopic structure that is capable of germinating to a new organism.
  3. The fungi stores carbohydrate as glycogen just like animal not as starch as done by plant

vii.       Their cell wall is made up of chitin and not cellulose like plant

Examples are Mucor, Rhizopus, Mushroom and Slime mould.

KINGDOM PLANTAE (Characteristic)

  1. They are multicellular and non-motile organisms
  2. Their cells are bounded by rigid cellulose cell walls external to cell membrane

iii.        They contain chlorophyll that enables them to manufacture their own food by photosynthesis

  1. Most plants store carbohydrates as starch or sucrose.

 

CLASSIFICATION OF KINGDOM PLANTAE BASED ON BOTANICAL CLASSIFICATION

The kingdom plantae is divided into four main phyla or Division

(i)         Thallophyta (algae)

–  They are simple microscopic plant

– They have no true root, stem and leaves

– They are found in aquatic habitat

-They are autotrophic plant i.e. They can synthesize their own food

– They reproduce both by asexual means and sexual means

– They have cellulose cell wall

– Many of them are pigmented such as red, blue, brown in addition to chlorophyll.

– Some are filamentous (algae) and the cells are not differentiated into tissue

(ii)        Bryophyte (Moss and liverwort)

– They are non-vascular multicellular plant

– They have chlorophyll as the only photosynthetic pigment

– They are terrestrial but grow in moist environment

– Their body is differentiated into stem-like and leaf-like structure but no true root, stem and leaves

– They have no vascular tissue therefore they are unable to transport food and material round the body

– They reproduce asexually by means of spores while sexual reproduction by gametes and it takes place in water

– They exhibit what is called alternation of generation.

Division Pteridophyta (ferns)

– Their body is divided into true root, stem and leaves

– They have well developed vascular bundles comprising of xylem and phloem

– The underground stem is rhizome

– They reproduce by means of spores

– They need water of sexual reproduction which is by gametes formation

– The plants are mostly terrestrial while few are aquatic

– They exhibit alternation of generation

– They  have asexual reproductive organ called sori while the sexual reproductive organ is heart- shaped called prothalus

SPERMATOPHYTA

– They are seed bearing plant

– They have well-developed vascular bundles

– They are well-adapted to terrestrial habitat and they are the most successful land plants

The Spermatophyta are divided into two:

(i)         Division Gymnospermatophyta or Coniferophyta

– They are large plant with well-developed vascular bundle with true root, stem and        leaves

– Their leaves are green in colour, small and needle-like

–  Their naked seeds are born in cone because there is no ovary and no fruit

(ii)        Division Angiospermatophyta

– They possess true flowers for sexual reproduction

– They have well-developed true root, stem and leaves

– They have well-developed vascular bundles

– Seeds and fruits are produced after fertilization and the seed are enclosed within the ovary

– They are terrestrial but some are aquatic

– They are terrestrial but some are aquatic

The Angiospermatophyta is divided into two classes

  1. Monocotylenoneae (Monocot)
  2. Dicotyledoneae (Dicot)

Monocotyledoneae                                                       Dicotyledonea
i.  Leaves have parallel veins                      Leaves have network veins

  1. Flowers are generally dull in colour Flowers are bright in colour

iii. Embryo has one cotyledon (one seed    Embryo has two cotyledons (two seed- leaves)

Leaf

  1. The size of cortex is narrow The size of the cortex is wide
  2. It has fibrous root system It has tap root system
  3. Cambium is absent in the stem    Cambium is present in the stem

vii. Vascular bundles are scattered all        Vascular bundle are arranged in a ring of cambium

over the ground tissue

Example Maize, palm tree, grasses      Examples are Mango, Orange.

 

CLASSIFICATION OF PLANTS BASED ON AGRICULTURE

Agricultural classification is the grouping of plants according to the product for which they are cultivated or grown

  1. CEREALS OR GRAIN CROPS: These are crops which are cultivated for their grain. They have high starch content. Examples are maize, guinea corn, millet, wheat, ryes, barley and oats.
  2. LEGIUMOUS PLANT OR POD: These are important plants which contain high protein content. They are source of nitrate in the soil. Examples are groundnut, beans, melon, flamboyant, crotalaria e.t.c.

iii.        ROOT CROPS: These are plant which are tuberous and are specialized for food storage. They are good source of carbohydrate. Examples are sweet potatoes, irish potatoes, yam, cassava and carrot  iv.    VEGETABLE CROPS: These are herbaceous plant which are important constituents of a diet. They serve as source of vitamins and mineral salts. Examples are tomatoes, pepper, onions, cabbage, lettuce, okra and vegetables.

 

  1. FRUITS: These are plants that are grown for production of fruits\. Fruits are rich sources of vitamin A, C and minerals. They are usually eaten in their natural form (raw). They include mangoes, pawpaw, guava, bananas, and pineapple e.t.c.
  2. CASH CROP (ECONOMIC CROP): These are crops grown mainly for the purpose of money making. They include oil producing plant e.g. oil palm, latex crop e.g. rubber, fibre crop e.g. cotton, beverage and drug plants e.g. cocoa and spices.

vii.       OIL PLANTS: These are plants that produce oil as food reserve and store it in their fruit or seeds. Example are palm oil fruit and kernel, seed of melon, cotton seed, groundnut, coconut and shea butter.

viii.      FIBRE CROPS: These are crops that \are grown for their fibres that are used for making clotting, ropes, sacks e.t.c.

  1. BEVERAGES AND DRUG PLANT: These are crops that produce non-alcoholic beverages e.g. cocoa, coffee.
  2. QUININE: is a drug that is obtained from the bark of cinchona spp. It is an anti-malaria drug extracted from plant.
  3. SPICES: These are vegetables plants that are used to add flavour and taste to modern dishes. Examples are ginger, cloves, pepper, vanilla, nutmeg.

            Classification of Plant based on life cycle

  1. ANNUAL: These are plants that have one growing season. They produce seeds during the first year of growing and then die off. Examples are maize, Guinea corn, wheat, groundnut, bean e.t.c
  2. BIENNIALS: These are plants that grow for two seasons. The first year constitutes the vegetable stage during which the store of food material is built up and seeds are produced in the second year e.g. cabbage, carrot, cocoyam, cassava e.t.c.
  3. PERENNIALS: These are plants that grow for three or more seasons or years e.g. shrub and three.

Relevance of Biology to Agriculture

Agriculture is defined as an act of growing crops and rearing farm animals to provide man’s basic need for

(i)         Food       (ii) Shelter       (iii) Clothing        (iv) Materials for industrial purposes

KINGDOM ANIMMALIA (Characteristic feature)

  1. All are multicellular organisms
  2. DNA is located in nucleus enclosed with nuclear membrane

iii.        Cells have no cell walls

  1. All possess nervous systems except the sponges
  2. All possess true tissue except sponges
  3. Feeding is heterotrophic

The Kingdom is divided into two major groups

(i)         INVERBRATA: These are groups of animal without backbone

(ii)        VERTEBRATA: These are groups of animal that have backbone

The classification of animals into smaller categories is based on features such as:

(i)         Body Symmetry

(ii)        Body design

(iii)       Body cavity

Body symmetry is based on the fact that the body of the animal has similar or corresponding parts in size, shape and position on opposite sides of a dividing line or a median plane

Types

  1. Radial symmetry means the body of the animal can be cut along its axis in any place to give two identical halves
  2. Bilateral symmetry means the body of the animal can be cut along its axis in only one place to give two identical halves.

Body design is the way the body of the animal is shaped or framed whether it has one or two exits

  1. Sac-like body design: Those animals that have single opening (mouth) that lead to the gut cavity
  2. Tubular body design: Those animals have double opening like tube with gut opening at the anterior (mouth) and posterior (anus)

Body Cavity: A developing embryo of animal has primary layer of cell called germ layer differentiated to form various body parts. The tissue of primitive animals are derived from two layers of cells, the ectoderm and endoderm such animal is called Diploblastic animal e.g. Hydra.

See also  LIVING THINGS AND NON-LIVING THINGS

Most animals are derived from three germs layers ectoderm, mesoderm and endoderm, such animal are called triploblastic animal.

Animal that have three germ layers can be further derived into:

  1. Acoelomate: animal without body cavity
  2. Pseudo coelomate: animal with false body cavity

iii.        Coelomate: animal with true body cavity

             The member of phylum invertebrate

  1. PORIFERA (Characteristic features)

– These are unicellular aquatic animals that usually attached to rocks or shell of other animals in colonies

– They are primitive animals that lack specialized tissue such as organs or system

– They have radial symmetry

– They have a single opening leading to internal cavity

Examples are the sponges which are vase-shaped with a symmetrical body.

  1. Phylum CNIDARIA OR COELENTERATA

The coelenterates are aquatic organisms which includes the sea anemone, jelly fish and corals which are marine organism, but hydra is found in fresh water

Characteristics

– They are multicellular organism

– They have radial symmetry

– They have only one body cavity called enteron

– They have two distinct body layers (diploblastic) ectoderm and endoderm.

– They have soft – jelly like bodies

– They reproduce asexually by budding

– They have one opening called mouth, no anus

– They have tentacles and stinging cells used for capturing their  preys (Nematocyst)

– They have specialized cells such as nerve sensory and absorptive cells.

  1. Phylum Platyhelminthes (Flatworm)

This group consists of the flatworms such as the planaria, flukes and tapeworms.

Characteristics

– They possess soft, flat and unsegimented body

– They have bilateral body symmetry

– They have no body cavity or lumen

– Their bodies is made up of three layers (triploblastic) ectoderm, mesoderm and endoderm

– Most flatworms are hermaphrodites and reproduce sexually

– Some of them are parasites in man and other animals

  1. Phylum Nematoda (Round worms)

The nematodes are the hookworms, Ascaris lumbricoides and guinea worms

Characteristics

– They have round and cylindrical bodies

– They lack body cavity i.e. they have pseudo- coelom body cavity

– They have bilateral body symmetry

– Some are hermaphrodites while some reproduce sexually.

  1. Phylum Annelida

The annelids are the earthworm, leeches ad tubeworms

Characteristics

– They have a true body cavity or coelom

– They have a metameric segmentation which means their body is both internally and externally            segmented, a feature which distinguish them from flat worms. Metameric segmentation means that body is divided into segments by position but have identical organ.

– some are aquatic while others are terrestrial

– Annelids reproduce sexually and many are hermaphrodites

– They are triploblastic animals

 

  1. Phylum Mollusca

The member of this phylum includes squid, mussel, periwinkles, snails, oyster, octopus and slug.

Characteristics

– They have soft-unregimented body

– They have tentacles on their heads

– They possess muscular foot adapted for crawling or borrowing

– Their body is covered by soft-tissue called mantle

– Some of them have calcerous shells e.g snail while some are without e.g. octopus

– Some are aquatic while some are terrestrial

– They have oculiferous tentacles which are used for sensitivity

  1. Phylum Arthropoda

This is the largest group in animal kingdom they have a distinct head with complex muscular system. The phylum is divided into four classes

  1. Crustacea e.g. crab, crayfish, prawn, lobster.
  2. Insecta e.g. all insects grasshopper, ant, termite e.t.c.
  3. Arachnida e.g. spider, scorpion, miles and tick
  4. Myriapoda e.g. centipede and millipede

Characteristics

– They have segmented bodies

– They have hard, rigid exoskeleton made of chitin bodies

– They have jointed appendages or jointed legs used for feeding, movement, reproduction or as sensory organs.

– They exhibit moulting or ecdysis i.e. shedding their exoskeleton at interval to permit growth

– Their bodies are divided into two or three segments such as head, thorax and abdomen which may be fused together in some member.

– They have bilateral body symmetry

– They are triploblastic animal

– They have various means of respiration e.g. gills, trachea, lung book or body surface.

  1. Phylum Echinodermata

These are the starfish, sea urchins, sea cucumbers and bristle star

Characteristics

– They have a radial body symmetry

– They are mostly marine

– They are triploblastic animals

– They have neither            nor brain

– Their body is not segmented

– They have true feet which are used for movement

             

VERTEBRATA

This is a sub phylum of the phylum chordate. It comprises of five classes. They are:

PISCES (fishes)

AMPHIBIA (Amphibians)

REPTILIA (Reptiles

AVES  (all birds)

MAMMALIA (mammals)

 

General Characteristics of Vertebrate

– They possess an internal jointed skeleton made up of cartilage or bone

– They all have bilateral symmetry

– The body is divided into head, trunk and tail

– They have two pairs of limbs (pectoral and pelvic) limbs.

– They have well- developed central nervous system with brain

– They have a closed blood system

– They possess skin which may be naked or have a covering of scales, feathers or hairs.

  1. CLASS PISCES (OSTERITHY)

The Pisces include all group of fishes, they show good adaptation to aquatic life. Fishes are of two types

  1. Bony fish: These are fishes with bony skeleton e.g. Tilapia, Salmon, Mackerel e.t.c.
  2. Cartilagenous fish: These are fishes whose bones are soft e.g. dry fish, shark, rays e.t.c.

Characteristics

– The body is covered by scales but few are without scales

– They possess fins which are used for movement in water

– They use gills for gaseous exchange

– They are poikilothermic or cold blooded animal meaning that their body temperature varies with that of their environment

– They have swim bladder for buoyancy

– They have lateral line for detection of vibration

– They have streamlined body shape for easy movement in water

– They are oviparous animal meaning that they lay egg which develop to adult stage outside the body of the female

             

CLASS AMPHIBIA

They are the first vertebrates to adapt to life on land and water. The member includes toad, frogs, salamander and newts

Characteristics

– They are poikilothermic animal

– They have two pairs of limbs-fore limbs and hind-limbs.

– They have naked or moist glandular skin with no external scales

– They exhibit dual life i.e. they can live both on land and water

– They carry out gaseous exchange with gills at tadpole stage of life and with lungs, skin and mouth at adult stage

– They are oviparous using external fertilization

             

CLASS REPTILIA

The reptile includes all reptiles with dry skin with scales or bony plate which resist loss of water from the         body. They are the first animal to have a copulatory organ (penis) for the purpose of internal fertilization. Examples are crocodile, lizard, wall gecko, snake e.t.c.

Characteristics

– They are poikilothermic animals

– They have dry skin covered with scales

– They all breathe with lungs

– They are oviparous animal

– They have homodont dentition meaning having set of teeth that are the same in shape and function.

– They use sexual reproduction with internal fertilization

– Some are aquatic animal e.g. crocodile and turtle while others are terrestrial

 

CLASS AVES (Birds)

The avers include all types of birds. They are mostly adapted to aerial life by means of wing which is a modification of the fore-limb. Examples of birds are pigeon, domestic fowls, ostrich, duck e.t.c.

Characteristics

– They are homoeothermic or warm blooded animal meaning they have a constant body temperature, it doesn’t change even when the temperature of its environment rises.

– The entire body of a bird is covered with feathers except the bird legs which are covered with scales

– The mouth is extended to form the beak which is used for feeding

– They have rigid hollow bones with air sac which make them light during flight

– They use internal fertilization

– They use lungs for respiration

– The fore-limbs modified to wings which are used for flight

– They are toothless but use beak for feeding

 

CLASS MAMMALIA (all mammals)

The mammals are the most advanced in the animal kingdom. They have two body cavities which is divided into two by a muscular sheet called diaphragm

Characteristics

– They are homoeothermic animal

– Their bodies are covered with hairs or furs

– They have heterodont dentition meaning having a set of teeth that are different in shape and function

– Their thoracic cavity is separated from the abdominal cavity by diaphragm

– They use lungs for respiration

– They have well developed brain

– They have external ear called pinnae

– They are viviparous made of reproduction meaning they give birth to their young ones alive

– They have a fully developed four chamber heart

– They all have a mammary gland which produces milk to feed their young ones

– They use sexual reproduction with internal fertilization

 

EFFECTS OF AGRICULTURAL ACTIVITIES ON ECOLOGICAL SYSTEM

An ecosystem is defined as a community of plants, animals and decomposers that interact with one another and with the non-living components of the environment, the balance in ecosystem may be interrupted by man through various activities such as

  1. BUSH CLEARING: is the act of clearing the bush by cutting down trees, clearing the shrubs and grasses for agricultural activities

EFFECT

– It exposes the soil to direct sunshine which may increase the temperature of the soil which may not favour the microorganism living within

– Removal of plants and trees exposes the soil to the threat of erosion

– Unprotected land or soil is subjected to leaching of nutrient by natural factor

– Extensive bush clearing may lead to desertification

– It may lead to migration or displacement of bush animals

– Bush clearing affects the existing ecosystem and set back succession of plants

– Bush clearing destroys conservation of plants species useful in other way.

2.BUSH BURNING: is defined as a deliberate or in deliberate act of setting the bush on      fire either        with a purpose or not at all

EFFECTS

– It kills both animals and microorganism within the engulfed area

– It may lead to gradual loss of soil fertility

– The burnt ashes may give the soil a slight alkaline content

– It will exposes the soil to both wind and rain erosion

– It takes longer time for micro-organism to return to the burnt soil

– It may reduce the water-retaining capacity of the soil

– Some plant species destroyed by the fire may not regenerate again on the soil

– The balanced ecosystem is totally destroyed.

– During burning some of the nutrients vapourise from the soil

            Few Advantages

– It renews the growth of dried up grasses easily (succession_

– It promotes speedy emergency of long dormant seeds of some plants

– the charcoal and wood are used for cooking

 

  1. TILLAGE

This is the activity of preparing the soil for use and growing of crops for consumption, storage and processing or Tillage is the practice of loosening the soil after clearing in preparation for growing. Hoes, spades and plough are used to break the soil

EFFECTS

– Ploughing loosens the soil and exposes it to erosion

– It brings about greater ecological changes of the soil

– Tillage encourages leaching of soil nutrients

– It damages structure and kill some of the micro-organisms

– Tillage increases the risk of fire and direct heat on the soil

              Advantages of Tillage

– It helps in loosening the soil and aid high crop yield

– it prevents appearance of different set of plants

– Tillage enhances proper aeration of the soil

  1. FERTILIZER

This is a natural or chemical substance which if spread on the land make plant grow well.

TYPES

– Organic fertilizer is a natural component which may include manure; fish meal and compost which are biologically origin and contain organic material are biologically origin and contain organic material

– Chemical fertilizer are chemical substance that are artificial in nature, they are described by their content e.g. Nitrogen, Phosphorus and potassium (NPK)

See also  Characteristics of living things

  

PESTICIDES AND HERBICIDES

A pesticide is a chemical compound used in agriculture to destroy organisms that can damage crops or stored food especially insect and rodent. Examples are insecticide and fungicide

A Herbicide is a chemical substance that kill plant or hamper their growth. It is known as weed-killer. It includes defoliants (contact herbicide) which kill only the parts they touch and selective herbicide which kill only certain plants and spare other.

Insecticides are chemical substance used to kill insects

EFFECTS

– It lead to loss of organic humus

– Chemical fertilizer when permeates can destroy the soil crumb structures

– Chemical such as herbicide and pesticide when washed down to the river can cause water pollution

– Extensive use of chemical fertilizer make soil dry and powdery and make it susceptible to wind erosion

– Chemical fertilizer can kill useful soil organisms when come in direct contact with them

 

EFFECTS OF DIFFERENT KIND OF FARMING ON ECOLOGICAL SYSTEM

CROP ROTATION

This is a method of farming system which accommodates the division of land into sections and on a different land, a different crop is planted on each section. The method reduces the risk of serious diseases infestations and soil depletion. Legumes are very important in crop rotation as it is believed to restores the nitrogen content of the soil or it adds nitrates to the soil. In crop rotation a surface feeder e.g. maize is planted along with deep feeder e.g. cassava. A surface feeder is a plant which grows near the surface and a deep feeder is a plant with firm root in the soil.

Benefit of crop rotation

– It allows the land to fallow

– It prevents erosion

– It increases the yield or crops

– It prevent disease infestation

– It adds nitrate to the soil

– Nutrients of the soil are not depleted

 

CROP ROTATION TABLE

1st plot 2nd plot 3rd plot 4th plot 5th plot
1st Year Maize Cassava Fallow Groundnut Yam
2nd Year Cassava Fallow Groundnut Yam Maize
3rd Year Fallow Groundnut Yam Maize Cassava
4th Year Groundnut Yam Maize Cassava Fallow
5th Year Yam Maize Cassava Fallow Groundnut

 

MIXED FARMING

            This is the system of farming that integrate both animal production and crop production on same farm.

Benefits

– It allows the animals to convert plant products to high quality protein needed by man

– It allays the fear of single crop failure

– The system is economically viable as the farmer makes money from both crop and animals.

MIXED CROPPING

This is a system of farming whereby the former grows more than one type of crop on a piece of land at the same time.

ADVERSE FARMING METHOD

CONTINUOUS CROPPING

This is a system of farming where a piece of land is permanently put under cultivation of crops

EFFECT

– The system leads of exhaution of essential minerals in the soil

– Cost of clearing is reduced as only an area is prepared for production

– Low productivity may be recorded after some years of using the land.

– There may be possibility of crop failure

 

MONOCULTURE OR MONOCROPPING

This is the system of farming that involves practice of growing the same crop on the same piece of land every year.

EFFECT

– It makes the environment unsuitable for many crops after few year

– The system encourages increased spread of both parasite and plant diseases

– The system can lead to crop failure which will affect the farmer financially

– The practices quickens the exhaustion and destruction of soil structure

 

SHIFT CULTIVATION

This is a system of farming where a piece of land is cultivated for either two or more years until the farmer notices low crop yield and abandons the farm land for another new piece of land.

EFFECT

– It leads to deforestation

– It leads to wastage of land

– it exposes the land to erosion

– It leads to migration of animals

 

THE PEST

A Pest is an insect or a small animal which can damage crops, spread diseases to man and other animals.

Types of Plant Pest

  1. Insect Pest: These are insects that are harmful to plant and cause damages to crop on field and at storage
  2. Crop eating insects can damage crops in various ways, their larvae chew their way into the roots while above surface insects feed on leaves, flowers and seeds./
  3. Sap-sucking insect: This group of insects constitute major problem, they weaken plant by stealing the energy rich sugar in sap and they also spread viruses that can cause disease. Example is aphid .
  4. Biting and chewing insects: They have the ability to destroy crops by eating up the leaves of young crops like maize, guinea corn, yam and vegetables.
  5. Piercing and sucking insects: These are insect pests having mouth parts adapted for piercing and sucking of crops. They pierce into young developing fruits, seeds and young stems and suck up the sap. Some of them inject poisonous chemicals into their saliva and cause distortion in growth of attached crop. Examples are cotton stainer, mealy bud, weevils and aphids

 

WORM PEST AND BORER

Some worms are subterranean, they feed on juicy roots of plants and destroy them making such plants to fall e.g. corn, while other worms chew their way up and feed on leaves, stems, flowers and feed  of plant.

(a)        Pod borer: They bore into fresh pod, eat up the seeds, introduce diseases and leave the pod to decay e.g. beans and soya beans

(b)        Stem borer: They bore holes into stem of crops, eat up the tissue and weakens the plant support e.g. maize, sorghum and millet

(c)        Army worm: The larvae of the worm engulf leaves and stem which retard growth and plant nutrient and reduce farm yield of crops e.g. maize, millet and sorghum

  1. ANIMAL PEST: These are animals either mammals or birds which destroy crops on the field

(a)        Mammal pest: They can invade maize farm and consume it to reduce the level of harvest. They can also destroy ripped palm fruit, yam and cassava crops example are monkeys, grass-cutter, ground squirrel, bush rat or rodent

(b)        Bird pest: They destroy grain farm within few days. They feed on young and dry corn, punch cassava and yam tubes and destroy groundnut. They can also feed on grains and banana e.g. bushes fowl, guinea fowl, village weaver birds.

EFFECT OF PEST

  1. insect pests such as grasshoppers can destroy the vegetation of several kilometres within few days

ii          Pests compete in feeding with humans and their effect can lead to scarcity or famine

iii.        Crop pests reduce the quality and quantity of infested crops, seeds and fruit

  1. They can cause financial disaster for farmers when they attacked and destroy stored produce
  2. They make the farmer to spend much money on pesticides and other method of control
  3. Some of the pests are agent of disease carrier deadly to both man and plant

            

Control Of Pests

  1. Chemical control is by the use of chemical substance that will bring about the killing of the pest e.g. Aldrin and vertox 85, Gammalin 20 and Didimac 25
  2. Cultural method of control involves the use of season, crop rotation, regular weeding, correct spacing and early harvest to confront the menace cause by pest

iii.        Physical method of control includes the use of scaring, killing and collecting pest for mass destruction. It also involves setting of traps, shooting, catapulting, scare-crows and the use of farm drum.

  1. Biological control: it involves introduction of natural enemies of the pest to consume the pest or to keep their population under control

  Life cycle of yam Beetle

The pest destroys large quantities of yam tubers annually by making hole or boring into the tubers. They bore into the tubers. The beetles live in the soil and in breeding seasons, they lay their eggs in damp places between November and December. The eggs hatch into larvae feeding on decaying matter at first, then on the root of grasses. They change into pupa and by March the adult beetle emerges and set off for feeding migration normally between April and June. They burrow themselves into the soil and it is here that they attack the yam tubers. They continue feeding up to October before setting off on breeding migration in November-December to seek damp places to lay their eggs and the cycle begins again.

 

 adults
Nymphs
Larvae

 

Life Cycle of Rhinoceros beetle

Rhinoceros beetles are pests that are found on the leaf bases of oil palm trees. They have potential or killing the tree. The life cycle begins when after mating the female beetles lay eggs at the bases of leaf stalks on live palm or on trunks of dead trees. Two weeks later, the eggs hatch into larvae having powerful mandibles which they use to eat dead wood.

   Egg
 Adults
Pupa
Larvae

After ninety days therefore, the larvae changes into a pupa in a cacoon, then 2-3 weeks later the adult emerge. The adult also feeds with the mandibles by burrowing into the dead wood like the larva. The effective means of control is by burning dead and discarded trees from the oil palm plantation

 

DISEASES OF AGRICULTURAL IMPORTANCE

A disease is defined as a deviation from the normal state of health presenting marked symptoms or outward visible signs. Diseases are group into:

i.Viral diseases: These are diseases of plant or animal caused by viruses. Examples of viral diseases in animals are foot and mouth diseases, Rinder pest and Newcastle. In plant, tobacco mosaic disease.

Ii .Bacterial disease: These are disease of plant or animal caused by bacteria. Examples of bacterial diseases of animal are Anthrax, Brucellosis and Tuberculosis. Example of bacterial disease of plant blight

iii. Fungi diseases: These are diseases of plant animals caused by different species of fungi. Examples are aspergilosis, ringworm, smut, rice blast, black pod disease of cocoa.

iv.Protozoa diseases of animal: These are the disease of farm animals caused by single- celled organisms such as Trypanosoma, Babesia Spp. The diseases include trypanosomiasis, Red water disease (piroplasmosis)

  General effect of Diseases

  1. Disease reduces the yield and productivity both in plant and animal
  2. Disease reduces the quality of crop and animal

iii.        They cause malformation in plant and animal

  1. They can kill or cause the death of the organism
  2. They cause reduction in the income of the farmer
  3. They increase the cause of production in the course of controlling them

vii.       They render both crops and animal unattractive and unmarketable

viii.      The activities of disease cause retarded growth both in crop and animals

            

General Control of Diseases

  1. Clearing breeding grounds of the animas
  2. Application of chemicals which ae available in different forms

iii.        Application of vaccines to induce immunity

  1. Good sanitation which helps to keep some of the parasite away
  2. Good feeding will ensures resistance to some parasite, hence animals should be adequately fed.
  3. Isolation of new stocks to ensure that they are free form infection

vii.       In case of cattle, practice rotational gracing

viii.      Changing animal beddings regularly

ix.        Employing the service of vetenary staff to check animal regularly

 

ASSIGNMENT

  1. Which of these is the odd one out? (a) bat     (b) shark      (c) rat      (d) whale
  2. Angiosperm and Gymnosperms belong to the class (a) schizophyta      (b)           pteridophyta

(c) spermatophyte     (d) bryophyte

  1. A distinguishing feature of mammals is the possession of (a) scale    (b) skin    (c) hair    (d) nail
  2. Insects and millipede have many features in common except (a) exoskeleton   (b) jointed

(c) compound eyes    (d) segmented body

  1. Make a labelled drawing of the lateral views of a fish
  2. State five structural differences between class pisces and class mammalian
  3. In a tabular form, state 5 differences between monocotyledons and cotyledons plant

 

See also

LIVING THINGS AND NON-LIVING THINGS

BIOLOGY AND INQUIRY

ADAPTATION

ECOLOGICAL MANAGEMENT

CONSERVATION OF NATURAL RESOURCES

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