Biodiversity

• Biodiversity


  Variety of life in all forms, levels and combinations
• Levels of biodiversity


  • Ecosystem Diversity
  • Species Diversity
  • Genetic Diversity
• Ecosystem Diversity


  • Variety and frequency of different ecosystems (e.g. marine coasts, grasslands, forests)
• Species Diversity


  • Frequency and diversity of different species, including domesticated and cultivated ones
• Genetic Diversity


  • Genetic differences between individuals within same population and between different populations of the same species, fundamental to allow species to adapt over time to environmental stresses it faces
• Classification


  Grouping organisms together based on common features to study, understand, identify and compare living things
• Reasons for classification


  • To reflect/show evolutionary relationships among organisms
  • For a more systematic procedure for naming, improving ability to predict morphology and behaviour of organisms and remember traits
  • Avoids ambiguity of common names
• Taxon


  A group of similar organisms
• Taxonomy


  The science of classification
• Types of classification


  • Artificial Classification
  • Natural Classification
  • Phylogenetic Classification
• Artificial Classification


  • Uses form and shape (morphology) to group organisms, relatively easy to follow but very superficial, focuses on morphological features with no importance to evolutionary relationships
• Natural Classification


  • Takes into account multiple features like anatomy, physiology, pathology, biochemistry, embryology, cytology to compare organisms and establish relationships, more accurate as it is not classified based on superficial features and considers evolutionary relationships
• Phylogenetic Classification


  • A type of natural classification based on evolutionary relationships between organisms, organisms in same group believed to have same ancestors
• Branches of Taxonomy


  • Nomenclature
  • Systematics
• Nomenclature


  Naming of organisms
• Systematics


  Grouping organisms based on similarities/differences
• Binomial Nomenclature


  System forged by Carl Linnaeus, using Genus and species to name unknown species
• Binomial Nomenclature examples


  • Genus species (unknown species)
  • Genus ssp. (sub-species)
  • Genus spp. (group multiple species)
• Systematics Hierarchy


  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
• Species


  A group of closely related organisms capable of interbreeding to produce fertile offspring, sharing a common genetic complement/genome and unique morphological/behavioural/ecological (niche) characteristics
• Mule is a product of mating two different species (male donkey and female horse), it is infertile with 63 chromosomes (odd number, gametes not viable)
• Five Kingdoms


  • Prokaryota
  • Protoctista
  • Fungi
  • Animalia
  • Plantae
• Prokaryota


  • No nuclear membrane or membrane bound organelles, free living or parasitic, autotrophic or heterotrophic (e.g. Escherichia coli, Salmonella sp.)
• Protoctista


  • Eukaryotic, unicellular or multicellular, resembling ancestors of modern plants, animals and early fungi (e.g. Amoeba sp., Paramecium sp., Chlorella sp., Euglena sp.)
• Fungi


  • Eukaryotic, unicellular or multicellular, heterotrophic (e.g. Mucor sp., yeast)
• Animalia


  • Eukaryotic, multicellular, heterotrophic (e.g. Homo sapiens, Felis leo, Canis familiaris)
• Plantae


  • Eukaryotic, multicellular, autotrophic (e.g. Tortula sp., Zea mays, Helianthus sp.)
• Protoctista


  A collection of eukaryotic organisms which do not fit neatly/exactly into other groups, resembling ancestors of modern plants, animals and early fungi, can be unicellular or multicellular, many are aquatic
• Protoctista subgroups


  • PROTOPHYTA (algae)
  • PROTOZOA
  • OOMYCOTA
• Protophyta


  • Photosynthetic organisms that evolved in and remained in the water, different from plants since parent gives no protection to zygote (i.e. no seeds), lack true stems, roots and leaves, no vascular tissue, have many growth forms
• Protophyta subgroups


  • Chlorophyta (green algae)
  • Rhodophyta (red algae)
  • Phaeophyta (brown algae)
• Chlorophyta


  • Both unicellular and multicellular, aquatic habitats like ponds, ditches, sea, photosynthetic pigments include chlorophyll a, chlorophyll b, carotenoids, store starch, have cellulose cell walls, some have flagella
• Chlorophyta examples


  • Chlamydomonas (unicellular, motile alga with large cup-shaped chloroplast)
  • Ulva sp. (thalloid, marine alga)
  • Chlorella sp.
  • Spirogyra (filamentous alga, unicellular but colonial, with helical chloroplast)
• Phaeophyta


  • Brown algae, some very large and complex multicellular, mostly marine, body is branched filaments or leaf-like growths, main food reserve is laminarin, have cellulose cell wall and outer gelatinous layer of algin
• Phaeophyta examples


  • Cystoseira spp.
  • Padina pavonica
  • Fucus sp. (marine alga found in intertidal areas, has adaptations like holdfast, dichotomous branching, air bladders)
• Phaeophyta adaptations


  • Holdfast for anchorage, dichotomous branching for streamlined structure, air bladders for buoyancy, chloroplasts in surface layers for maximum light exposure, pigment fucoxanthin to absorb blue wavelengths, secrete mucus/mucilage to retain moisture
• Protozoa


  Unicellular, animal-like cells, heterotrophic nutrition, mostly free-living, sometimes parasitic, found in aquatic environments
• Protozoa subgroups


  • Rhizopoda
  • Ciliaphora
  • Apicomplexa
• Rhizopoda - Amoeba sp.


  • Use pseudopodia for movement, asexual reproduction by binary fission, holozoic nutrition by ingesting food through endocytosis, aerobic respiration, have contractile vacuole for osmoregulation
• Ciliaphora - Paramecium sp.

  • More protoplasmic differentiation than Amoeba, lives in stagnant/slow-flowing freshwater, has cilia for locomotion, avoidance reaction, asexual and sexual reproduction, contractile vacuole for osmoregulation, oral groove for feeding