FORM III TOPICS •
•
heterotrophic
fast response to stimuli (tactic)
• have specialized excretory structures
1. a) i) What is meant by the term
binomial nomenclature? c) Describe the economic importance of:
• scientific system of naming organisms using the
i. Fungi
generic(genus) and specific (species) names
• some cause decay to our food
• some cause diseases to humans and animals e.g.
ii) State briefly the general principles of classification ringworms
of living organisms • may be used as food e.g. mushrooms, yeast
• some are used in production of antibiotics e.g.
• scientific names must be in Latin or should be penicillin, chloromycin, streptomycin
latinised • yeast is used in brewing industry, baking and
• family names are formed by adding the suffix source of vitamin B
“idea” to the stem of the genus e.g. the genus • many cause diseases to our crops e.g. late blight
Rana become Ranaidea • important in recycling nutrients in soil since they
• generic names should be a single unique name cause decay of organic matter
• mycorrhizal association in forest development
may help in water intake/absorption
b) State the main characteristics of the five kingdoms
• help in nitrogen fixation
of organisms
i. Monera
Bacteria
• e.g. bacteria
• unicellular (single celled) • are useful in the manufacture of antibiotics
• prokaryotic (genetic material not surrounded by • silage formation,
membrane) • fermentation of cheese, butter, milk yoghurt
• cell wall without cellulose • curing of tea, tobacco and retting flax
• lack most organelles • formation of vitamin B12 and K
• small in size (microscopic) • enzymes such as amylase and invertase
ii. Protista(protoctista) • hormones such as insulin
• single celled(unicellular) • vinegar, acetic acid, lactic acid, citric acid
• eukaryotic (most cell organelles present) • in septic tanks and modern sewage works make
• when cell walls are present have no cellulose use of bacteria
• e.g. protozoa and algae • biogas production
• usually microscopic • saprophytic bacteria are used in compost
iii. Fungi decomposition or cause decay
• have hyphae (which form mycelia) • symbiotic bacteria are used in compost
• absence of chlorophyll decomposition or cause decay
• have rhizoids (lack roots, leaves, stem) • symbiotic bacteria in herbivores/ruminants help
• have spore forming structures (sporangia) in digestion
• e.g. mucor, rhizopus • some diseases in animals/humans and plants are
iv. Plantae caused by bacteria
• most are green/contain chlorophyll • many bacteria cause food spoilage/decay
• autotrophic/feed by photosynthesis • nitrifying and nitrogen fixing bacteria increase
• cells have cellulose cell walls soil fertility/make nitrates available
• respond slowly to stimuli (tropism) • denitrifying bacteria reduce soil fertility/convert
• lack locomotion (are stationary) nitrates into nitrogen/reduce nitrates
• indefinite growth (at meristems)
• lack specialized excretory structures
v. Animalia d) State the main characteristics of the following
• cells do not have cell walls division of kingdom plantae
• most carry out locomotion
www.arena.co.ke 0713779527
, i. Bryophyte • ovules contained in ovary
• e.g. mosses and liverworts iii. Name the classes and state characteristics
• presence of rhizoids of angiospermae
• lack of vascular tissues (lack phloem and xylem) Dicotyledonae
• body parts not differentiated into root, stem,
leaves
• capsule or seta • two seed leaves
• gametophyte generation dominant. • network venation of leaves
• regularly arranged vascular bundles
ii. Pteridophyta • tap root system
• e.g. ferns • broad leaves
• has true roots, stems and leaves • secondary growth occurs
• fond with sori on under-surface Monocotyledonae
• vascular tissues present • one seed leaf
• sporophyte generation is dominant • parallel venation of leaves
• irregularly arranged vascular bundles
• fibrous root system
• narrow leaves
• sheath like leaf stalk (petiole)
• no secondary growth
iii. Spermatophyte
• photosynthetic
• well differentiated into roots, stems and leaves
• well developed vascular system
• seed bearing plants
iv) State the importance of plants
e) Name sub-divisions of spermatophyte and state the • balancing carbon IV oxide and oxygen in the
characteristics of each class atmosphere during photosynthesis and
i. Gymnospermae (cornifers) respiration
• naked seeds (exposed • influence water cycle
• are all woody trees • reduce soil erosion by bind soil particles
• reproduce by means of cones together
• show xerophytic characteristics • useful products e.g. food, medicine, timber,
paper and clothing
• xylem have tracheids but lack vessels
• habitat ( e.g. forests and grassland) for animals
• phloem lacks companion cells
which may also be tourist attraction
• single fertilization
• earn money from sales of products
• pollen lands directly on ovules
• aesthetic value/beauty e.g. flowers,
shade/shelter, live fences, windbreaks
ii. Angiospermae (flowering plants) • Some are harmful e.g. poisons, weeds, injurious
(stinging nettles, thorns), water hyacinth.
• reproduce by flowers
• seeds enclosed (in fruits) f) i) Give the general characteristics of phylum
• flowers bisexual hence double fertilization arthropoda
• herbaceous
• jointed appendages
• pollen grains land on stigma of pistil
• presence of exoskeleton
• xylem contains vessels
• triploblastic and coelomate
• phloem contains companion cells
• segmented body
www.arena.co.ke 0713779527
, • bilateral symmetry (similar halves) Arachnida
ii. State the characteristics of the following
classes of arthropoda • body divided into two parts( abdomen and
cephalothorax)
• simple eyes
Diplopoda • eight legs (four pairs of legs)
• the millipedes
• two pairs of legs per segment iii) State the economic importance of insects
• many segments
• terrestrial habitat
• body cylindrical and long Beneficial effects
• herbivorous
• one pair of antennae • food supply
• important in food chains
• pollinators
Chilopoda • biological control of pests and other organisms
• the centipedes • aesthetic value
• one pair of legs per segment • contribute to decomposition e.g. litter feeders
• many segments like beetles
• terrestrial habitat
• body long and ventro-dorsally flattened Harmful effects
• carnivorous
• last pair of legs pointing backwards with poison • pests
claws called maxillipedes • vectors
• one pair of antennae • dirt and disease carriers
• injurious e.g. stings and bites
Insecta
g) i) State the general characteristics of chordate
• three body parts i.e. head thorax, abdomen
• six legs/three pairs of legs • notochord
• a pair of compound eyes • dorsal slits (pharyngeal cleft during
• presence of wings development)
• a pair of antennae • bilateral symmetry
• triploblastic (three layer body-ectoderm,
mesoderm and endoderm)
• clear cut head formation
• multilayered epidermis
• post anal tail
• closed circulatory system
• segmented muscle blocks(myotomes)
• single pair of gonads
Crustacean
• two body parts
• segmented body
• have pincers (modified legs) to catch prey
• have hard exoskeleton
• a pair of compound eyes
www.arena.co.ke 0713779527
, • hollow bones
• oviparous (lay eggs)
• mouths modified into beaks
Give the characteristics of the following classes of
chordate
Pisces
• presence of fins for locomotion
• two chambered heart
• presence of overlapping scales
• presence of gills or operculum for gaseous
exchange
• presence of lateral line for protection
• streamlined body
• poikilothermic (body temperature varies with Mammalian
that of environment)
• hair on the body
• homoeothermic
Amphibian • viviparous (give birth to live young) except a
few
• partially live in fresh water and partially on land • have mammary glands
• poikilothermic • glandular skin e.g. sweat glands, sebaceous
• pentadactylous with two pairs of limbs glands
• webbed feet for locomotion in water • four chambered heart
• body streamlined • pinna (external ear)
• heart is three chambered • two pairs of pentadactyl limbs
• moist skin for gaseous exchange • presence of diaphragm
• have salivary glands
Reptilia
• scales on body a) i) What is a dichotomous key?
• poikilothermic
• homodont teeth except tortoise and turtle • A biological device (tool) which enables one to
• all have limbs except snakes identify an organism by progressively opting
between two alternative observable
• skin is dry
characteristics
• oviparous (lay eggs)
• no pinna (external ear)
• three chambered heart 9crocodile has four i. State the necessity of using a
chambers) dichotomous key
• skin not glandular
• no mammary glands
• used to identify organisms quickly and
accurately
Aves • by following the statements in the key we are
able to identify each organism on the basis of a
• the birds characteristic which is not to be found in other
• homoeothermic (constant body temperature) specimens
• four chambered heart
• streamlined body for locomotion in air
• skin dry and covered by feathers ii. List the rules followed in
• scales on legs constructing a dichotomous key
www.arena.co.ke 0713779527
•
heterotrophic
fast response to stimuli (tactic)
• have specialized excretory structures
1. a) i) What is meant by the term
binomial nomenclature? c) Describe the economic importance of:
• scientific system of naming organisms using the
i. Fungi
generic(genus) and specific (species) names
• some cause decay to our food
• some cause diseases to humans and animals e.g.
ii) State briefly the general principles of classification ringworms
of living organisms • may be used as food e.g. mushrooms, yeast
• some are used in production of antibiotics e.g.
• scientific names must be in Latin or should be penicillin, chloromycin, streptomycin
latinised • yeast is used in brewing industry, baking and
• family names are formed by adding the suffix source of vitamin B
“idea” to the stem of the genus e.g. the genus • many cause diseases to our crops e.g. late blight
Rana become Ranaidea • important in recycling nutrients in soil since they
• generic names should be a single unique name cause decay of organic matter
• mycorrhizal association in forest development
may help in water intake/absorption
b) State the main characteristics of the five kingdoms
• help in nitrogen fixation
of organisms
i. Monera
Bacteria
• e.g. bacteria
• unicellular (single celled) • are useful in the manufacture of antibiotics
• prokaryotic (genetic material not surrounded by • silage formation,
membrane) • fermentation of cheese, butter, milk yoghurt
• cell wall without cellulose • curing of tea, tobacco and retting flax
• lack most organelles • formation of vitamin B12 and K
• small in size (microscopic) • enzymes such as amylase and invertase
ii. Protista(protoctista) • hormones such as insulin
• single celled(unicellular) • vinegar, acetic acid, lactic acid, citric acid
• eukaryotic (most cell organelles present) • in septic tanks and modern sewage works make
• when cell walls are present have no cellulose use of bacteria
• e.g. protozoa and algae • biogas production
• usually microscopic • saprophytic bacteria are used in compost
iii. Fungi decomposition or cause decay
• have hyphae (which form mycelia) • symbiotic bacteria are used in compost
• absence of chlorophyll decomposition or cause decay
• have rhizoids (lack roots, leaves, stem) • symbiotic bacteria in herbivores/ruminants help
• have spore forming structures (sporangia) in digestion
• e.g. mucor, rhizopus • some diseases in animals/humans and plants are
iv. Plantae caused by bacteria
• most are green/contain chlorophyll • many bacteria cause food spoilage/decay
• autotrophic/feed by photosynthesis • nitrifying and nitrogen fixing bacteria increase
• cells have cellulose cell walls soil fertility/make nitrates available
• respond slowly to stimuli (tropism) • denitrifying bacteria reduce soil fertility/convert
• lack locomotion (are stationary) nitrates into nitrogen/reduce nitrates
• indefinite growth (at meristems)
• lack specialized excretory structures
v. Animalia d) State the main characteristics of the following
• cells do not have cell walls division of kingdom plantae
• most carry out locomotion
www.arena.co.ke 0713779527
, i. Bryophyte • ovules contained in ovary
• e.g. mosses and liverworts iii. Name the classes and state characteristics
• presence of rhizoids of angiospermae
• lack of vascular tissues (lack phloem and xylem) Dicotyledonae
• body parts not differentiated into root, stem,
leaves
• capsule or seta • two seed leaves
• gametophyte generation dominant. • network venation of leaves
• regularly arranged vascular bundles
ii. Pteridophyta • tap root system
• e.g. ferns • broad leaves
• has true roots, stems and leaves • secondary growth occurs
• fond with sori on under-surface Monocotyledonae
• vascular tissues present • one seed leaf
• sporophyte generation is dominant • parallel venation of leaves
• irregularly arranged vascular bundles
• fibrous root system
• narrow leaves
• sheath like leaf stalk (petiole)
• no secondary growth
iii. Spermatophyte
• photosynthetic
• well differentiated into roots, stems and leaves
• well developed vascular system
• seed bearing plants
iv) State the importance of plants
e) Name sub-divisions of spermatophyte and state the • balancing carbon IV oxide and oxygen in the
characteristics of each class atmosphere during photosynthesis and
i. Gymnospermae (cornifers) respiration
• naked seeds (exposed • influence water cycle
• are all woody trees • reduce soil erosion by bind soil particles
• reproduce by means of cones together
• show xerophytic characteristics • useful products e.g. food, medicine, timber,
paper and clothing
• xylem have tracheids but lack vessels
• habitat ( e.g. forests and grassland) for animals
• phloem lacks companion cells
which may also be tourist attraction
• single fertilization
• earn money from sales of products
• pollen lands directly on ovules
• aesthetic value/beauty e.g. flowers,
shade/shelter, live fences, windbreaks
ii. Angiospermae (flowering plants) • Some are harmful e.g. poisons, weeds, injurious
(stinging nettles, thorns), water hyacinth.
• reproduce by flowers
• seeds enclosed (in fruits) f) i) Give the general characteristics of phylum
• flowers bisexual hence double fertilization arthropoda
• herbaceous
• jointed appendages
• pollen grains land on stigma of pistil
• presence of exoskeleton
• xylem contains vessels
• triploblastic and coelomate
• phloem contains companion cells
• segmented body
www.arena.co.ke 0713779527
, • bilateral symmetry (similar halves) Arachnida
ii. State the characteristics of the following
classes of arthropoda • body divided into two parts( abdomen and
cephalothorax)
• simple eyes
Diplopoda • eight legs (four pairs of legs)
• the millipedes
• two pairs of legs per segment iii) State the economic importance of insects
• many segments
• terrestrial habitat
• body cylindrical and long Beneficial effects
• herbivorous
• one pair of antennae • food supply
• important in food chains
• pollinators
Chilopoda • biological control of pests and other organisms
• the centipedes • aesthetic value
• one pair of legs per segment • contribute to decomposition e.g. litter feeders
• many segments like beetles
• terrestrial habitat
• body long and ventro-dorsally flattened Harmful effects
• carnivorous
• last pair of legs pointing backwards with poison • pests
claws called maxillipedes • vectors
• one pair of antennae • dirt and disease carriers
• injurious e.g. stings and bites
Insecta
g) i) State the general characteristics of chordate
• three body parts i.e. head thorax, abdomen
• six legs/three pairs of legs • notochord
• a pair of compound eyes • dorsal slits (pharyngeal cleft during
• presence of wings development)
• a pair of antennae • bilateral symmetry
• triploblastic (three layer body-ectoderm,
mesoderm and endoderm)
• clear cut head formation
• multilayered epidermis
• post anal tail
• closed circulatory system
• segmented muscle blocks(myotomes)
• single pair of gonads
Crustacean
• two body parts
• segmented body
• have pincers (modified legs) to catch prey
• have hard exoskeleton
• a pair of compound eyes
www.arena.co.ke 0713779527
, • hollow bones
• oviparous (lay eggs)
• mouths modified into beaks
Give the characteristics of the following classes of
chordate
Pisces
• presence of fins for locomotion
• two chambered heart
• presence of overlapping scales
• presence of gills or operculum for gaseous
exchange
• presence of lateral line for protection
• streamlined body
• poikilothermic (body temperature varies with Mammalian
that of environment)
• hair on the body
• homoeothermic
Amphibian • viviparous (give birth to live young) except a
few
• partially live in fresh water and partially on land • have mammary glands
• poikilothermic • glandular skin e.g. sweat glands, sebaceous
• pentadactylous with two pairs of limbs glands
• webbed feet for locomotion in water • four chambered heart
• body streamlined • pinna (external ear)
• heart is three chambered • two pairs of pentadactyl limbs
• moist skin for gaseous exchange • presence of diaphragm
• have salivary glands
Reptilia
• scales on body a) i) What is a dichotomous key?
• poikilothermic
• homodont teeth except tortoise and turtle • A biological device (tool) which enables one to
• all have limbs except snakes identify an organism by progressively opting
between two alternative observable
• skin is dry
characteristics
• oviparous (lay eggs)
• no pinna (external ear)
• three chambered heart 9crocodile has four i. State the necessity of using a
chambers) dichotomous key
• skin not glandular
• no mammary glands
• used to identify organisms quickly and
accurately
Aves • by following the statements in the key we are
able to identify each organism on the basis of a
• the birds characteristic which is not to be found in other
• homoeothermic (constant body temperature) specimens
• four chambered heart
• streamlined body for locomotion in air
• skin dry and covered by feathers ii. List the rules followed in
• scales on legs constructing a dichotomous key
www.arena.co.ke 0713779527
