Comprehensive Biology Study Guide:
From Living Things to the Five Kingdoms
1. Characteristics of Life (The "MRS GREN" Functions)
To be considered "alive," an organism must exhibit seven key functions:
●​ Movement: Action causing a change of position of the whole organism or parts (e.g.,
plants turning toward light).
●​ Respiration: Chemical reactions in cells that break down nutrients to release energy for
metabolism.
●​ Sensitivity: Ability to detect internal/external stimuli and respond appropriately.
●​ Growth: Permanent increase in size and dry mass (from within).
●​ Reproduction: Creation of the next generation (sexual or asexual) to ensure survival.
●​ Excretion: Removal of toxic materials and metabolic waste (e.g.,
respiration).
●​ Nutrition: Taking in materials for energy, growth, and development.
produced during
2. Classification of Organisms (Taxonomy)
●​ Artificial Classification: Based on a few easily observed characteristics for practical
convenience (often arbitrary).
●​ Natural (Biological) Classification: Based on evolutionary relationships, common
ancestry, and internal/external features.
●​ Binomial Nomenclature (Carl Linnaeus):
○​ Format: Genus (capitalized) followed by Species (lowercase).
○​ Rule: Must be italicized or underlined.
●​ Taxonomic Hierarchy (Broad to Specific): Kingdom
Phylum (or Division)
Class
Order
Family
Genus
Species.
●​ Species Definition: Organisms with similar features capable of breeding to produce
fertile offspring (e.g., the mule is infertile, so donkeys and horses are distinct species).
3. The Five Kingdoms
Kingdom Animalia
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Structure: Eukaryotic, multicellular, specialized for active living.
Cell Biology: Lack cell walls and photosynthetic pigments.
Nutrition: Heterotrophic (ingest organic material).
Energy Storage: Store carbon as glycogen and fat.
Subdivisions:
○​ Vertebrates: Possess a backbone (Fish, Amphibians, Reptiles, Birds, Mammals).
○​ Invertebrates: Lack a backbone (Insects, Mollusks).
●​ Insects: Body divided into Head, Thorax, and Abdomen. Possess an exoskeleton and 3
pairs of legs. Undergo metamorphosis (Complete: Egg-Larva-Pupa-Adult; or Incomplete).
Kingdom Plantae
●​ Cell Biology: Eukaryotic, multicellular. Cellulose cell wall, contain chloroplasts
(chlorophyll).
●​ Nutrition: Autotrophic (photosynthesis).
●​ Energy Storage: Store carbohydrates as starch.
●​ Divisions:
○​ Bryophyta: Non-vascular (lack roots/stems/leaves). Need moisture for reproduction
via spores (e.g., Mosses, Liverworts, Hornworts).
○​ Pteridophyta: Vascular, seedless. Reproduce via spores. Stems often grow as
underground rhizomes (e.g., Ferns).
○​ Gymnosperms: Vascular, "naked" seeds in cones (e.g., Conifers).
○​ Angiosperms: Vascular, flowering plants. Seeds enclosed in fruit (e.g., Maize, Beans).
Kingdom Protista
●​ Characteristics: Eukaryotic, unicellular. Diverse nutrition.
●​ Protozoans (Animal-like): Lack cell walls. Ingest solid food (e.g., Amoeba, Paramecium).
●​ Protophyta (Plant-like): Possess cell walls and chloroplasts. Perform photosynthesis (e.g.,
Euglena, Chlamydomonas).
●​ Examples: Plasmodium (malaria), Trypanosomes.
Kingdom Monera
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Characteristics: Prokaryotic, unicellular.
Cell Wall: Composed of protein and polysaccharide (not cellulose).
Reproduction: Asexual (binary fission).
Blue-green algae (Cyanobacteria): Photosynthetic. Contain chlorophyll + carotenoids +
blue pigment (phycobilin). First organisms to produce
as a byproduct.
●​ Bacteria: Extremely small. Shapes: spherical, rod, spiral. Some use flagella for movement.
DNA contained in a nucleoid region.
Kingdom Fungi
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Characteristics: Eukaryotic, unicellular (yeast) or multicellular (mushrooms, molds).
Structure: Thread-like filaments called hyphae.
Cell Wall: Composed of chitin.
Nutrition: Heterotrophic (saprophytic decomposers or parasitic).
Energy Storage: Store carbon as glycogen.
Examples:
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○​ Yeast: Unicellular; converts carbohydrates into alcohol and
○​ Mould: Grows on decayed food (e.g., Penicillium).
○​ Mushrooms: Spore-bearing fruiting body produced above ground.
4. Key Biological Terms
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Prokaryotic: Cells lacking a defined nucleus/organelles.
Eukaryotic: Cells with a membrane-bound nucleus.
Vascular: Tissue (xylem/phloem) for transport.
Non-vascular: Lacks transport tissue; depends on moist environments.
Autotrophic: Self-feeding organisms.
Heterotrophic: Consumes other organisms.
Motile: Ability to move independently.
Hyphae: Thread-like fungal structures.
Poikilothermic: Cold-blooded; body temperature fluctuates.
Homoeothermic: Warm-blooded; maintains constant body temperature.