CLASSIFICATION OF LIVING THINGS
The classification of living things refers to the grouping of organisms based on their structural, genetic, and cellular organization. This process is known as taxonomy. The current system of classification used today was established by a Swedish naturalist named Carl Von Linne (1707-1778), more commonly known by his Latin name, Carolus Linnaeus. Linnaeus published the classification of plants in 1753 and animals in 1758.
Table of Contents
Living things are initially categorized into a broad group called a kingdom. Within each kingdom, there are smaller groups known as phyla (or divisions, primarily for plants). Phyla are further divided into classes, and each class is subdivided into orders. Orders are then broken down into families, and families are divided into genera. A genus consists of closely related species, and a species refers to a population of organisms that can interbreed and produce fertile offspring.
In this hierarchical system, a family is a group of genera, an order is a group of related families, a class is a group of related orders, a phylum is a group of related classes, and a kingdom is a group of related phyla.
The modern classification system, based on physiological, biochemical, and embryological characteristics, classifies living things into five kingdoms: Monera, Protoctista, Fungi, Plantae, and Animalia.
MONERA (Characteristics)
Monera, also known as prokaryotes, exhibit the following characteristics:
1. Their DNA is not organized within a nucleus but rather scattered in the cytoplasm, lacking a membrane-bound nucleus.
2. They lack mitochondria in their cytoplasm.
3. Their cell walls are composed of proteins and fatty materials, lacking cellulose.
4. They are microscopic single-celled organisms.
5. Some of them are motile, while others are non-motile.
6. They can obtain nutrition through autotrophic and heterotrophic means. Examples include blue-green bacteria and blue-green algae.
7. Reproduction in Monera occurs solely through asexual means.
KINGDOM PROTOCYISTA (Characteristics)
Kingdom Protoctista, also known as Protista, displays the following characteristics:
1. They possess well-organized DNA contained within a nucleus enclosed by a nuclear membrane. This characteristic classifies them as eukaryotes.
2. Protoctista consists of single-celled organisms or unicellular organisms.
3. Within this kingdom, some protists exhibit motility, while others are non-motile.
4. They inhabit various environments such as water, damp soil, leaf litter, and other terrestrial habitats that provide sufficient moisture.
5. All protists rely on mitochondria for cellular respiration, utilizing these organelles to generate energy.
6. To endure unfavorable conditions, protists have the ability to form protective cysts, aiding in their survival.
7. Protists reproduce through both sexual and asexual means. Examples of protists include Amoeba, Euglena, Chlamydomonas, and Plasmodium.
It is important to note that examples of Monera, a different kingdom, include bacteria and photosynthetic blue-green bacteria, commonly referred to as blue-green algae.
KINGDOM FUNGI (Characteristics)
Kingdom Fungi exhibit the following characteristics:
1. Fungi are heterotrophic organisms as they lack chlorophyll, preventing them from undergoing photosynthesis. Consequently, they obtain nutrients by feeding on organic matter.
2. While fungi may resemble plants in their growth patterns, they are distinct from plants as they do not possess green pigmentation.
3. Fungi do not possess true roots, stems, or leaves that are typically observed in plant anatomy.
4. They are primarily non-motile organisms composed of thread-like, multinucleate structures known as hyphae. These hyphae collectively form a network called mycelium, which is responsible for the growth and nutrient absorption of the fungus.
5. Fungi reproduce through the production of spores. These unicellular, microscopic structures have the ability to germinate and give rise to new fungal organisms.
6. Unlike plants, fungi store carbohydrates in the form of glycogen, similar to animals, rather than as starch.
7. The cell walls of fungi are composed of chitin, a structural polysaccharide, rather than cellulose, which is typically found in plant cell walls.
Examples of fungi include Mucor, Rhizopus, Mushroom, and Slime mold, representing the diverse forms and types within the kingdom.
KINGDOM PLANTAE (Characteristic)
- They are multicellular and non-motile organisms
- Their cells are bounded by rigid cellulose cell walls external to cell membrane
- They contain chlorophyll that enables them to manufacture their own food by photosynthesis
- 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 plants i.e. They can synthesize their own food
– They reproduce both by asexual means and sexual means
– They have a cellulose cell wall
– Many of them are pigmented such as red, blue, and 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 structures 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 a rhizome
– They reproduce by means of spores
– They need water for 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 habitats and they are the most successful land plants
The Spermatophyta are divided into two:
(i) Division Gymnospermatophyta or Coniferophyta
– They are large plant with a well-developed vascular bundle with true root, stem, and leaves
– Their leaves are green in color, 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
- Monocotylenoneae (Monocot)
- Dicotyledoneae (Dicot)
Monocotyledoneae Dicotyledonea
i. Leaves have parallel veins Leaves have network veins
- Flowers are generally dull in color Flowers are bright in color
iii. Embryo has one cotyledon (one seed Embryo has two cotyledons (two seed- leaves) Leaf
- The size of cortex is narrow The size of the cortex is wide
- It has fibrous root system It has tap root system
- 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 trees, grasses Examples are Mango, Orange.
CLASSIFICATION OF PLANTS BASED ON AGRICULTURE
Agricultural classification involves the categorization of plants based on the specific product they are cultivated or grown for.
1. Cereals or Grain Crops: These crops are primarily cultivated for their grains, which have a high starch content. Examples of such crops include maize, guinea corn, millet, wheat, rye, barley, and oats.
2. Leguminous Plants or Pods: These plants are significant sources of protein and serve as a natural nitrate source in the soil. Examples include groundnut, beans, melon, flamboyant, crotalaria, and others.
3. Root Crops: These plants are characterized by tuberous structures specialized for food storage and serve as valuable sources of carbohydrates. Examples of root crops include sweet potatoes, Irish potatoes, yam, cassava, and carrots.
4. Vegetable Crops: Herbaceous plants that form essential components of a balanced diet, providing vitamins and mineral salts. Examples of vegetable crops include tomatoes, peppers, onions, cabbage, lettuce, okra, and various other vegetables.
5. Fruits: These plants are cultivated for the production of edible fruits. Fruits are rich sources of vitamins A, C, and minerals. They are typically consumed raw. Examples of fruit crops include mangoes, papayas, guavas, bananas, pineapples, and more.
6. Cash Crops (Economic Crops): These crops are primarily grown for commercial purposes and profit-making. They include oil-producing plants like oil palm, latex crops such as rubber, fiber crops like cotton, as well as beverage and drug plants like cocoa and spices.
7. Oil Plants: These plants produce oil as a food reserve, storing it in their fruits or seeds. Examples include palm oil fruit and kernel, melon seed, cottonseed, groundnut, coconut, and shea butter.
8. Fiber Crops: These crops are cultivated for their fibers, which are used in the production of clothing, ropes, sacks, and other products.
9. Beverage and Drug Plants: These crops are grown to produce non-alcoholic beverages, such as cocoa and coffee. Additionally, certain plants yield medicinal substances, for example, quinine extracted from the bark of cinchona spp., which is used as an anti-malaria drug.
10. Spices: These are vegetable plants that add flavor and enhance the taste of various dishes. Examples of spices include ginger, cloves, pepper, vanilla, nutmeg, and more.
Classification of Plant based on life cycle
- 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
- 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.
- 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 ANIMALIA (Characteristic feature)
Characteristic features of Kingdom Animalia include:
1. Multicellularity: All organisms belonging to Kingdom Animalia are composed of multiple cells.
2. Nucleus and DNA: The DNA of animal cells is contained within a nucleus, which is enclosed by a nuclear membrane.
3. Absence of Cell Walls: Unlike plant cells, animal cells do not possess cell walls.
4. Nervous Systems: With the exception of sponges, all animals have nervous systems that enable them to respond to stimuli and interact with their environment.
5. Tissues: Except for sponges, animals have true tissues, which are specialized groups of cells that work together to perform specific functions.
6. Heterotrophic Feeding: Animals are heterotrophs, meaning they obtain their nutrition by consuming other organisms or organic matter.
It’s important to note that these characteristics collectively define animals within Kingdom Animalia, distinguishing them from other kingdoms in the biological classification system.
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: This refers to the characteristic of an animal’s body that can be divided along any axis to create two identical halves.
2. Bilateral Symmetry: This describes an animal’s body structure that can only be divided along a single axis to yield two identical halves.
3. Body Design: Body design refers to the overall shape or framework of an animal’s body, including the number of exits it possesses.
– Sac-like Body Design: This refers to animals that have a single opening (mouth) that leads directly into the gut cavity.
– Tubular Body Design: Animals with a tubular body design have two openings, one at the anterior end (mouth) and the other at the posterior end (anus), resembling a tube-like structure.
4. Body Cavity: During the development of an animal embryo, the primary layer of cells called germ layers differentiate to form various body parts. Primitive animals have tissues derived from two layers of cells known as the ectoderm and endoderm, and they are referred to as diploblastic animals (e.g., Hydra).
However, most animals have three germ layers – ectoderm, mesoderm, and endoderm – and are classified as triploblastic animals.
– Acoelomate: These animals lack a true body cavity.
– Pseudocoelomate: This describes animals with a false body cavity, where the body cavity is not entirely lined with mesoderm.
– Coelomate: Animals with a coelom have a true body cavity, which is completely lined with mesoderm.
These categorizations help classify animals based on their symmetry, body design, and the presence or absence of a body cavity.
The member of phylum invertebrate
PORIFERA (Characteristic features)
– These are unicellular aquatic animals that usually attached to rocks or shells 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 the internal cavity
Examples are the sponges which are vase-shaped with a symmetrical body.
Phylum CNIDARIA OR COELENTERATA
The coelenterates are aquatic organisms which include the sea anemone, jellyfish, and corals which are marine organism, but hydra is found in freshwater
Characteristics
– They are multicellular organism
– They have radial symmetry
– They have only one body cavity called the 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 a mouth, no anus
– They have tentacles and stinging cells used for capturing their prey (Nematocyst)
– They have specialized cells such as nerve sensory and absorptive cells.
Phylum Platyhelminthes (Flatworm)
This group consists of the flatworms such as planaria, flukes, and tapeworms.
Characteristics
– They possess soft, flat, and unsegmented body
– They have bilateral body symmetry
– They have no body cavity or lumen
– Their bodies are 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
Phylum Nematoda (Roundworms)
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.
Phylum Annelida
Annelids, including earthworms, leeches, and tubeworms, possess the following characteristics:
– They have a well-developed body cavity known as a coelom.
– Annelids exhibit metameric segmentation, both internally and externally. This distinctive feature sets them apart from flatworms. Metameric segmentation refers to the division of the body into segments that are positioned similarly and contain identical organs.
– Some annelids are adapted to aquatic environments, while others inhabit terrestrial habitats.
– Annelids reproduce sexually, and many species are hermaphrodites, possessing both male and female reproductive organs.
– They are triploblastic animals, meaning their body development involves three germ layers: ectoderm, mesoderm, and endoderm.
In summary, annelids are characterized by their body cavity, segmented structure, adaptability to different environments, sexual reproduction, and triploblastic nature.
Phylum Mollusca
The member of this phylum includes squid, mussel, periwinkles, snails, oyster, octopus and slug.
Characteristics
– They have a 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 snails while some are without e.g. octopus
– Some are aquatic while some are terrestrial
– They have oculiferous tentacles which are used for sensitivity
Phylum Arthropoda
This is the largest group in the animal kingdom they have a distinct head with a complex muscular system. The phylum is divided into four classes
- Crustacea e.g. crab, crayfish, prawn, lobster.
- Insecta e.g. all insects grasshopper, ant, termite e.t.c.
- Arachnida e.g. spider, scorpion, miles, and tick
- 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 intervals to permit growth
– Their bodies are divided into two or three segments such as the head, thorax, and abdomen which may be fused together in some members.
– They have bilateral body symmetry
– They are triploblastic animal
– They have various means of respiration e.g. gills, trachea, lung book or body surface.
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 subphylum of the phylum chordate. It comprises 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 a 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 that may be naked or have a covering of scales, feathers, or hairs.
CLASS PISCES (OSTERITHY)
The Pisces include all groups of fishes, they show good adaptation to aquatic life. Fishes are of two types
- Bony fish: These are fishes with bony skeletons e.g. Tilapia, Salmon, Mackerel e.t.c.
- Cartilaginous fish: These are fishes whose bones are soft e.g. dry fish, sharks, rays e.t.c.
Characteristics
– The body is covered by scales but few are without scales
– They possess fins that are used for movement in the water
– They use gills for gaseous exchange
– They are poikilothermic or cold-blooded animals meaning that their body temperature varies with that of their environment
– They have swim bladders for buoyancy
– They have lateral lines for the detection of vibration
– They have streamlined body shapes for easy movement in the water
– They are oviparous animals meaning that they lay eggs that develop to the 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 on water
– They carry out a gaseous exchange with gills at the tadpole stage of life and with lungs, skin, and mouth at the adult stage
– They are oviparous using external fertilization
CLASS REPTILIA
The reptile includes all reptiles with dry skin with scales or bony plates 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 a set of teeth that are the same in shape and function.
– They use sexual reproduction with internal fertilization
– Some are aquatic animals e.g. crocodiles and turtles 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 pigeons, domestic fowls, ostrich, ducks e.t.c.
Characteristics
– They are homoeothermic or warm-blooded animals meaning they have a constant body temperature, it doesn’t change even when the temperature of their 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 sacs 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 beaks for feeding
CLASS MAMMALIA (all mammals)
Mammals are the most advanced in the animal kingdom. They have two body cavities which is divided into two by a muscular sheet called the 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 the diaphragm
– They use lungs for respiration
– They have a well-developed brain
– They have external ears called pinnae
– They are viviparous and 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 that produces milk to feed their young ones
– They use sexual reproduction with internal fertilization
EFFECTS OF AGRICULTURAL ACTIVITIES ON THE 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 the ecosystem may be interrupted by man through various activities such as
1. BUSH CLEARING:
This 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 favor 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 nutrients by natural factor
– Extensive bush clearing may lead to desertification
– It may lead to the migration or displacement of bush animals
– Bush clearing affects the existing ecosystem and sets back the succession of plants
– Bush clearing destroys the conservation of plant species useful in other ways.
2. BUSH BURNING:
This is defined as a deliberate or deliberate act of setting the bush on fire either with a purpose or not at all
EFFECTS
– It kills both animals and microorganisms within the engulfed area
– It may lead to a gradual loss of soil fertility
– The burnt ashes may give the soil a slightly alkaline content
– It will expose the soil to both wind and rain erosion
– It takes a longer time for micro-organisms 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
Advantages
– It renews the growth of dried-up grasses easily (succession_
– It promotes speedy emergency of long dormant seeds of some plants
– charcoal and wood are used for cooking
3. 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 in the soil
– Tillage encourages leaching of soil nutrients
– It damages the structure and kills 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 aids high crop yield
– it prevents the appearance of different sets of plants
– Tillage enhances proper aeration of the soil
4. FERTILIZER
This is a natural or chemical substance which if spread on the land makes the plant grow well.
TYPES
– Organic fertilizer is a natural component that may include manure; fish meal and compost which are biologically origin and contain organic material are biological origins and contain organic material
– Chemical fertilizers are chemical substances that are artificial in nature, they are described by their content e.g. Nitrogen, Phosphorus, and potassium (NPK)
PESTICIDES AND HERBICIDES
A pesticide refers to a chemical compound employed in agriculture to eliminate organisms that pose a threat to crops or stored food, particularly insects and rodents. Examples of pesticides include insecticides and fungicides.
A herbicide is a type of chemical substance that is utilized to eradicate plants or hinder their growth. It is commonly known as a weed killer. Herbicides encompass two main categories: defoliants (contact herbicides), which kill only the parts of plants they come into direct contact with, and selective herbicides, which target specific plants while sparing others.
Insecticides, on the other hand, are chemical substances specifically designed to kill insects.
EFFECTS
– The utilization of chemical fertilizer results in the depletion of organic humus.
– When chemical fertilizers seep into the soil, they can disrupt the soil’s crumb structure.
– Herbicides and pesticides, if washed into rivers, can contribute to water pollution.
– Excessive application of chemical fertilizers can render the soil dry and powdery, making it more susceptible to wind erosion.
– Direct contact with chemical fertilizers can harm beneficial soil organisms, potentially leading to their demise.
EFFECTS OF DIFFERENT KINDS OF FARMING ON ECOLOGICAL SYSTEM
CROP ROTATION
Crop rotation is a farming system that involves dividing land into sections and planting different crops on each section. This method offers several advantages, including reducing the risk of serious disease infestations and soil depletion. One crucial component of crop rotation is the inclusion of legumes, which play a vital role in restoring nitrogen content in the soil or adding nitrates to it. In this practice, a surface feeder plant, such as maize, is planted alongside a deep feeder plant, such as cassava. Surface feeders grow near the soil surface, while deep feeders have robust roots that penetrate deep into the soil.
The benefits of crop rotation are as follows:
1. Fallow Period: Crop rotation allows the land to fallow, meaning it is left unplanted for a specific period. This resting period helps rejuvenate the soil, replenishing its nutrients and preventing exhaustion.
2. Erosion Prevention: By alternating crops, crop rotation helps prevent soil erosion. Different crops have varying root structures and depths, which contribute to better soil structure and stability.
3. Increased Crop Yield: Crop rotation has been shown to increase overall crop yield. By alternating crops, the soil is not continuously depleted of specific nutrients, leading to improved soil fertility and enhanced productivity.
4. Disease Prevention: Rotating crops disrupt the life cycle of pests and pathogens. Different crops have varying susceptibility to diseases and pests. By changing the crop species in each section, the risk of serious disease infestations is reduced.
5. Nitrate Addition: Incorporating legumes into crop rotation enriches the soil with nitrogen. Legumes have a unique ability to form a symbiotic relationship with nitrogen-fixing bacteria in their root nodules. This process allows legumes to convert atmospheric nitrogen into a usable form for plants, thus adding nitrates to the soil.
6. Nutrient Preservation: Crop rotation helps maintain nutrient balance in the soil. Different crops have varying nutrient requirements, and rotating crops ensures that specific nutrients are not excessively depleted from the soil.
In summary, crop rotation is an effective farming practice that offers numerous benefits, including fallowing the land, erosion prevention, increased crop yield, disease prevention, nitrate addition, and preservation of soil nutrients. By implementing crop rotation, farmers can maintain soil health, productivity, and sustainability over the long term.
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 integrates both animal production and crop production on the 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 crops 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 to the exhaustion 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 the possibility of crop failure
MONOCULTURE OR MONOCROPPING:
This is the system of farming that involves the practice of growing the same crop on the same piece of land every year.
EFFECT
– It makes the environment unsuitable for many crops after a few years
– The system encourages the increased spread of both parasite and plant diseases
– The system can lead to crop failure which will affect the farmer financially
– The practices quicken 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 farmland for another new piece of land.
EFFECT
– It leads to deforestation
– It leads to the wastage of land
– it exposes the land to erosion
– It leads to the migration of animals
THE PEST
A Pest is an insect or a small animal that can damage crops, and spread diseases to man and other animals.
Types of Plant Pest
Insect pests pose a significant threat to plants and can cause extensive damage to crops both in the field and during storage. Here are some further details on different types of insect pests:
1. Crop-Eating Insects: These insects can harm crops in various ways. Their larvae tunnel into plant roots, while above-surface insects feed on leaves, flowers, and seeds. This feeding behavior can lead to severe damage to the plant’s structure and productivity.
2. Sap-Sucking Insects: This group of insects presents a major problem as they extract the sugar-rich sap from plants, weakening them in the process. Additionally, sap-sucking insects can transmit viruses that cause diseases in plants. An example of a sap-sucking insect is the aphid.
3. Biting and Chewing Insects: Insects in this category have the ability to destroy crops by consuming the leaves of young plants such as maize, guinea corn, yam, and vegetables. Their feeding behavior can result in defoliation and a significant reduction in crop yield.
4. Piercing and Sucking Insects: These insect pests possess specialized mouthparts adapted for piercing and sucking plant tissues. They penetrate into young developing fruits, seeds, and stems to extract sap. Some of these insects inject toxic substances through their saliva, leading to distortion in the growth of affected crops. Examples of piercing and sucking insects include cotton stainers, mealybugs, weevils, and aphids.
These various types of insect pests can cause significant harm to plants and crops, leading to economic losses for farmers and potential food security concerns. Effective pest management strategies are crucial to mitigate the negative impacts of insect pests on agricultural systems.
WORM PEST AND BORER
Different types of pests pose threats to crops, including worms, animals, and insects. Here are further details on specific pests and their effects, as well as methods of pest control:
1. Worms:
– Some subterranean worms feed on plant roots, causing destruction that leads to plant collapse. Examples include cornworms.
– Other worms chew their way up and consume leaves, stems, and flowers of plants.
(a) Pod Borer: These worms bore into fresh pods, consuming the seeds, introducing diseases, and causing the pods to decay. Crops like beans and soybeans are commonly affected.
(b) Stem Borer: These worms create holes in crop stems, consuming the plant tissue and weakening the plant’s structural support. Crops such as maize, sorghum, and millet are vulnerable.
(c) Armyworm: The larvae of armyworms devour leaves and stems, inhibiting growth and nutrient absorption in plants. Maize, millet, and sorghum are frequently targeted.
2. Animal Pests:
– Mammal pests and bird pests are animals that destroy crops in the field.
(a) Mammal Pests: Animals like monkeys, grass-cutters, ground squirrels, and rodents can invade maize farms, consume crops, and reduce harvest levels. Ripe palm fruit, yam, and cassava crops are also susceptible to damage.
(b) Bird Pests: Birds such as bush fowl, guinea fowl, and village weaver birds can rapidly destroy grain farms. They feed on young and dry corn, puncture cassava and yam tubers, and damage groundnuts, grains, and bananas.
Effects of Pest Infestation:
– Insect pests like grasshoppers can decimate vegetation over large areas in a short period.
– Pests compete with humans for food resources, potentially leading to scarcity or famine.
– Crop pests reduce the quality and quantity of infested crops, seeds, and fruits.
– Pest attacks can result in financial disasters for farmers when stored produce is destroyed.
– Farmers incur significant expenses on pesticides and other control methods.
– Some pests act as carriers of diseases that can be deadly to both humans and plants.
Pest Control Methods:
– Chemical Control: The use of chemical substances, such as Aldrin, Vertox 85, Gammalin 20, and Didimac 25, aims to eliminate pests.
– Cultural Methods: Practices like seasonality, crop rotation, regular weeding, correct spacing, and early harvest are employed to combat pests.
– Physical Methods: Scaring, killing, and collecting pests for mass destruction, as well as setting traps, shooting, using scarecrows, and employing farm drums, are physical control approaches.
– Biological Control: This method involves introducing natural enemies of pests to consume or control their populations, helping to maintain a balance in ecosystems and reduce pest damage.
By implementing effective pest control strategies, farmers can mitigate the negative impact of pests on crop production, improve yields, and protect their agricultural investments.
The life cycle of Yam Beetle
The life cycle of the Yam Beetle involves several stages, from egg-laying to adult reproduction:
1. Egg-laying: During the breeding season, which typically occurs between November and December, the adult Yam Beetles lay their eggs. These eggs are deposited in damp areas, providing a suitable environment for development.
2. Larval Stage: After hatching from the eggs, the larvae of the Yam Beetle begin their life by feeding on decaying matter. As they progress, they transition to consuming the roots of grasses, which serve as their primary food source during this stage.
3. Pupal Stage: As the larvae mature, they undergo a transformative stage known as pupation. Within pupal cases, the larvae undergo significant physiological changes to prepare for adulthood.
4. Emergence of Adult Beetles: By March, the adult Yam Beetles emerge from their pupal cases. At this point, they embark on a feeding migration that typically takes place between April and June. During this period, the beetles actively search for food sources to sustain themselves.
5. Feeding and Tuber Infestation: After the feeding migration, the adult beetles burrow themselves into the soil. It is during this phase that they specifically target yam tubers. By tunneling into the tubers, they cause damage by making holes or boring into them. This destructive behavior can lead to the loss of significant quantities of yam tubers.
6. Continued Feeding and Breeding: The Yam Beetles continue their feeding activities throughout the months, feeding on yam tubers until around October. By November and December, they commence their breeding migration once again, searching for suitable damp locations to lay their eggs. This marks the beginning of a new cycle for the Yam Beetle life cycle.
The destructive behavior of the Yam Beetle, particularly in attacking yam tubers, poses a significant challenge for yam farmers. Implementing effective pest control measures during the appropriate stages of the beetle’s life cycle can help mitigate the damage caused and protect yam crops.
| egg in the ground |
| adults |
| Nymphs |
| Larvae |
Life Cycle of Rhinoceros beetle
The life cycle of the Rhinoceros beetle, a pest commonly found on the leaf bases of oil palm trees, involves several stages:
1. Mating and Egg-laying: After mating, the female Rhinoceros beetles lay their eggs. These eggs are typically deposited at the bases of leaf stalks on live palm trees or on the trunks of dead trees. This location provides a suitable environment for the development of the larvae.
2. Egg Hatching: Approximately two weeks after being laid, the eggs hatch, giving rise to larvae. These larvae possess powerful mandibles, which they utilize for feeding on dead wood.
3. Larval Stage: During the larval stage, the Rhinoceros beetle larvae continue to feed on the dead wood, utilizing their strong mandibles to break down the material. This stage is crucial for their growth and development.
4. Pupal Stage: After a period of feeding and growth, the Rhinoceros beetle larvae undergo a pupal stage. During pupation, the larvae transform into a dormant pupa enclosed within a protective cocoon. This stage is a critical period of metamorphosis, where the larvae undergo physical changes to develop into adult beetles.
5. Emergence of Adult Beetles: After completing the pupal stage, the Rhinoceros beetles emerge as fully formed adult beetles. They break out of the pupal cocoon and make their way to the surface. The adult beetles have hardened exoskeletons and are equipped with wings for mobility.
6. Feeding and Reproduction: As adult beetles, they engage in feeding activities. Rhinoceros beetles primarily feed on plant material, including the leaf bases of oil palm trees. Their feeding behavior can potentially cause damage to the trees, especially if the infestation is severe. Additionally, the adult beetles reproduce, continuing the life cycle by mating and laying eggs.
The life cycle of the Rhinoceros beetle can have significant implications for oil palm plantations, as severe infestations can lead to the weakening and potential death of palm trees. Effective pest management strategies, such as monitoring and targeted control measures, are essential to mitigate the damage caused by Rhinoceros beetles and protect the health of oil palm crops.
| Egg |
| Adults |
| Pupa |
| Larvae |
After ninety days, therefore, the larvae change into a pupa in a cacoon, then 2-3 weeks later the adult emerges. 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
Diseases can be defined as deviations from the normal state of health, characterized by marked symptoms or visible signs. They are categorized into different groups:
1. Viral Diseases: These diseases affect plants or animals and are caused by viruses. Examples of viral diseases in animals include foot and mouth disease, Rinderpest, and Newcastle disease. In plants, a well-known viral disease is tobacco mosaic disease.
2. Bacterial Diseases: These diseases affect plants or animals and are caused by bacteria. Examples of bacterial diseases in animals include Anthrax, Brucellosis, and Tuberculosis. A common bacterial disease in plants is blight.
3. Fungal Diseases: These diseases affect plants or animals and are caused by various species of fungi. Examples include Aspergillosis, Ringworm, Smut, Rice blast, and Black pod disease of cocoa.
4. Protozoan Diseases: These diseases affect animals and are caused by single-celled organisms such as Trypanosoma and Babesia species. Diseases caused by protozoans include trypanosomiasis and Red water disease (piroplasmosis).
The general effects of diseases include:
– Reduction in yield and productivity in both plants and animals.
– Decrease in the quality of crops and animals.
– Induction of malformations in plants and animals.
– Potential fatality or death of the affected organism.
– Reduction in the income of farmers due to decreased production.
– Increased production costs incurred in disease control measures.
– Rendering crops and animals unattractive and unmarketable.
– Retarded growth in both crops and animals.
General methods for disease control include:
– Clearing breeding grounds for animals to reduce disease transmission.
– Application of various forms of chemical treatments to control diseases.
– Administration of vaccines to induce immunity in animals.
– Implementation of good sanitation practices to minimize parasite presence.
– Providing proper nutrition to animals, which enhances resistance to some parasites.
– Isolating new stocks to ensure they are free from infection.
– Practicing rotational grazing in cattle to minimize disease transmission.
– Regularly changing animal bedding to reduce disease spread.
– Engaging the services of veterinary staff to conduct regular health checks on animals.
By implementing these disease control measures, farmers can mitigate the impact of diseases, maintain the health and productivity of their crops and animals, and ultimately safeguard their agricultural livelihoods.
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