Biology

• Science is defined as a systematic process of making enquiry about the living things and non-living things in our environment
• Biology


  The study of life, ranging from the unicellular organisms to the study of global interaction among millions of organisms that forms life
• Specific aspects of Biology

  • Morphology
  • Anatomy
  • Physiology
  • Genetics
  • Ecology
  • Virology
  • Bacteriology
  • Microbiology
  • Taxonomy
  • Histology
  • Mycology
  • Embryology
  • Evolution
• Scientific process or approach

  • Observation
  • Hypothesis
  • Experiment
  • Aim
  • Apparatus/Materials
  • Method or Procedure
  • Result
  • Conclusion
• Hypothesis


  A sensible proposal or reasonable assumption or a scientific guess that can be subjected to verification or being tested
• Experiment


  The process used for testing of hypothesis through experimentation during which data are collected
• Theory


  A tested hypothesis that has been confirmed to be true
• Law or Principle


  A theory that has been extensively tested and proven to be true
• Characteristics of living things

  • Movement
  • Nutrition
  • Respiration
  • Excretion
  • Growth
  • Irritability/Sensitivity
  • Reproduction
  • Adaptation
  • Competition
  • Death
• Plants and animals have different characteristics
• Microscope


  An instrument used to view or magnify organisms smaller that 0.001mm which cannot be seen by human naked eyes
• Parts of a microscope

  • Eyepiece lens or ocular
  • Body tube
  • Revolving nose piece
  • Coarse focus knob
  • Fine adjustment knob
  • Arm
  • Stage
  • Clips
  • Hole
  • Condenser
  • Mirror
  • Base of the microscope
• Living things are classified into five kingdoms: Monera, Protoctista, Fungi, Plantae and Animalia
• Monera


  • Lack organized DNA, no mitochondrion, cell wall lacks cellulose, microscopic single called organism, some motile some non-motile, feed both autotrophically and heterotrophically, reproduce only by asexual means
• Protoctista


  • Have well organized DNA in the nucleus, single called or unicellular organism, some motile some non-motile, live in water, damp soil, leaf litter and other terrestrial habitats, use mitochondrion for cellular respiration, form cyst to survive adverse condition, reproduce both sexually and asexually
• Fungi


  • Feed heterotrophically, simple multicellular organism, not divided into true root, stem and leaves, mostly non-motile composed of thread-like multinucleate hyphae, reproduce by means of spores, store carbohydrate as glycogen, cell wall made of chitin
• Plantae


  • Multicellular and non-motile, cells bounded by rigid cellulose cell walls, contain chlorophyll for photosynthesis, store carbohydrates as starch or sucrose
• Organism that grow like plant but are not plant

  • Not green in colour
  • Body not divided into true root, stem and leaves
  • Mostly non-motile organisms composed of thread-like multinucleate hyphae collectively known as mycelium
  • Reproduce by means of spores (unicellular microscopic structure that is capable of germinating to a new organism)
  • Store carbohydrate as glycogen like animal, not starch like plant
  • Cell wall made up of chitin, not cellulose like plant
• Organisms that grow like plant but are not plant

  • Mucor
  • Rhizopus
  • Mushroom
  • Slime mould
• Kingdom Plantae


  • Multicellular and non-motile organisms
  • Cells bounded by rigid cellulose cell walls external to cell membrane
  • Contain chlorophyll that enables them to manufacture their own food by photosynthesis
  • Most plants store carbohydrates as starch or sucrose
• Divisions of Kingdom Plantae

  • Thallophyta (algae)
  • Bryophyte (Moss and liverwort)
  • Pteridophyta (ferns)
  • Spermatophyta
• Thallophyta (algae)


  • Simple microscopic plant
  • No true root, stem and leaves
  • Found in aquatic habitat
  • Autotrophic (can synthesize their own food)
  • Reproduce both by asexual and sexual means
  • Have cellulose cell wall
  • Many are pigmented such as red, blue, brown in addition to chlorophyll
  • Some are filamentous and the cells are not differentiated into tissue
• Bryophyte (Moss and liverwort)


  • Non-vascular multicellular plant
  • Have chlorophyll as the only photosynthetic pigment
  • Terrestrial but grow in moist environment
  • Body differentiated into stem-like and leaf-like structure but no true root, stem and leaves
  • No vascular tissue, unable to transport food and material round the body
  • Reproduce asexually by means of spores, sexually by gametes in water
  • Exhibit alternation of generation
• Pteridophyta (ferns)


  • Body divided into true root, stem and leaves
  • Well developed vascular bundles comprising of xylem and phloem
  • Underground stem is rhizome
  • Reproduce by means of spores, sexual reproduction by gametes formation in water
  • Mostly terrestrial, few aquatic
  • Exhibit alternation of generation
  • Asexual reproductive organ is sori, sexual reproductive organ is heart-shaped prothalus
• Divisions of Spermatophyta


  • Gymnospermatophyta or Coniferophyta
  • Angiospermatophyta
• Gymnospermatophyta or Coniferophyta


  • Large plant with well-developed vascular bundle with true root, stem and leaves
  • Leaves are green in colour, small and needle-like
  • Naked seeds born in cone because there is no ovary and no fruit
• Angiospermatophyta


  • Possess true flowers for sexual reproduction
  • Have well-developed true root, stem and leaves
  • Have well-developed vascular bundles
  • Seeds and fruits are produced after fertilization and the seed are enclosed within the ovary
  • Terrestrial but some are aquatic
• Classes of Angiospermatophyta


  • Monocotylenoneae (Monocot)
  • Dicotyledoneae (Dicot)
• Differences between Monocot and Dicot

  • Leaves have parallel veins (Monocot) vs Leaves have network veins (Dicot)
  • Flowers are generally dull in colour (Monocot) vs Flowers are bright in colour (Dicot)
  • Embryo has one cotyledon (Monocot) vs Embryo has two cotyledons (Dicot)
  • Size of cortex is narrow (Monocot) vs Size of the cortex is wide (Dicot)
  • Has fibrous root system (Monocot) vs Has tap root system (Dicot)
  • Cambium is absent in the stem (Monocot) vs Cambium is present in the stem (Dicot)
  • Vascular bundles are scattered all over the ground tissue (Monocot) vs Vascular bundle are arranged in a ring of cambium (Dicot)
• Agricultural classification of plants

  • Cereals or grain crops
  • Legiumous plant or pod
  • Root crops
  • Vegetable crops
  • Fruits
  • Cash crop (economic crop)
  • Oil plants
  • Fibre crops
  • Beverages and drug plant
  • Spices
• Cereals or grain crops


  Crops cultivated for their grain, have high starch content
• Legiumous plant or pod


  Important plants which contain high protein content, source of nitrate in the soil
• Root crops


  Tuberous plants specialized for food storage, good source of carbohydrate
• Vegetable crops


  Herbaceous plants which are important constituents of a diet, serve as source of vitamins and mineral salts
• Fruits


  Plants grown for production of fruits, rich sources of vitamin A, C and minerals, usually eaten raw
• Cash crop (economic crop)


  Crops grown mainly for the purpose of money making, include oil producing, latex, fibre, beverage, drug and spice plants
• Oil plants


  Plants that produce oil as food reserve and store it in their fruit or seeds
• Fibre crops


  Crops grown for their fibres that are used for making clothing, ropes, sacks
• Beverages and drug plant


  Crops that produce non-alcoholic beverages and drugs
• Quinine


  Anti-malaria drug extracted from the bark of cinchona spp.