Members of a species are similar (phenotype) to each other but
different from other species
Similarity of organisms in same species can be
physical (branching pattern of trees)
biochemical (haemoglobin structure)
immunological (antibody against an antigen equally effective)
development (similar growth of embryos)
ecological (occupy identical ecological niche)
(Group of) organisms able to interbreed/reproduce giving
fertile offspring
Each species is reproductively isolated from every other
species
The five-kingdom classification of organisms
Nomenclature: Naming of organisms
Binomial: Biological name of an organism → Genus
species
Taxon: Set of organisms within a category / Taxonomy / Study of
biological classification
Different levels of taxons: SPECIES, GENUS, FAMILY, ORDER,
CLASS, PHYLUM, KINGDOM
Most number of species on right
Most similar organisms on left
Unicellular: Single cell; Colonial: Groups of cells;
Multicellular: Many cells
Autotrophs produce energy from inorganic sources
Phototrophs from photosynthesis/sunlight
Chemotrophs from simple inorganic (oxidative) processes
Heterotrophs digest and absorb organic molecules
Prokaryotae (prokaryotes)
Cell structure:
Prokaryotes, unicellular
Prokaryotes lack cytoplasmic organelles found in eukaryotes
Cell wall: murein
Nutrition: autotrophic (photosynthesis, chemosynthesis),
aerobic heterotrophs
Divide by binary fission, not by mitosis
≈10μm in size (bacterial cell, filaments of
blue-green bacteria)
Mutualistic nitrogen-fixing bacteria live in nodules on the
root of legumes / symbiotic
Protoctista (protoctists)
Cell structure: eukaryotes, unicellular and multicellular
Cell wall: (sometimes) polysaccharide
Nutrition: autotrophic, heterotrophic
Placed in this category by exclusion / cannot be placed in any
other kingdom
Slime moulds / fungi characteristics
Protozoa / heterotrophic and ingest food
Algae / photosynthesis
≈10μm (amoeba) - 1m (Laminaria / large brown
alga)
Fungi
Cell structure: eukaryotes, multicellular and unicellular
(yeast)
Cell wall: chitin
Nutrition: heterotrophic / saprotrophic decomposers or
parasitic
Genus Penicillium
Body of a fungus is composed of thin filaments called hyphae /
form a mycelium
Secret enzymes / external digestion / absorbs resulting
nutrients
Erect hyphae that grow upwards from the mycelium carry their
reproductive spores
Chains of spores on the erect hyphae / coloured mould visible on
stored food
Break down organic matter
Plantae (plants)
Cell structure: only multicellular, eukaryotic; large vacuoles
Cell wall: cellulose
Nutrition: autotrophic (photosynthetic)
Growth is restricted to meristems (layers/patches of dividing
cells)
Non-motile; adapted to land / strong tissues, leave gas
exchange system, waterproofed
Eg mosses, ferns, conifers, angiosperms (flowering plants)
Plant kingdom has two different types of adults in their life
cycle
Gametophytes, hidden in plant / sexual reproduction forms
multicellular zygotes
Sporophytes, what we call plant / asexual reproduction to form
spores that germinate into gametophytes
Gametophyte (n) → gamete (n) → fertilisation →
zygote (2n) → mitosis → sporophyte (2n) → meiosis → spore (n) → mitosis →
gametophyte (n)
Animalia (humans, animals)
Cell structure: eukaryotic, multicellular, no cell wall
Develop form a blastocyst / embryo
Have nervous and hormonal control systems
No cell wall!
Nutrition: heterotrophic, involving a digestive system
Are motile and grow throughout tissues (no mersitems)
Viruses → acellular → not included in
classification system → pathogenic
Ecosystem
Ecosystem
Five Kingdoms
Human Activity
Inheritance
Nutrient Cycle
Photosynthesis
Selection
Variation
Content
Definition of species (basic unit of classification):
The five-kingdom classification of organisms
Prokaryotae (prokaryotes)
Protoctista (protoctists)
Fungi
Plantae (plants)
Plant kingdom has two different types of adults in their life
cycle
Animalia (humans, animals)
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