biodiversity

• Biological species concept


  A group of organisms with similar MORPHOLOGICAL (structure features), physiological (Way how body works), which can breed to produce a fertile offspring allowing gene flow from parent to the offsprings, and reproductively isolated from other species, they occupy same niche
• Morphological species concept


  A group of living organisms that share many physical features that distinguish them from other species, grouped together according to physical characteristics
• Ecological species concept


  Based on ecological niche (role of the organism in the environment) occupied by organism
• Limitations of biological species concept: organisms in a species can't attempt to interbreed to produce fertile offspring as they are not all living in same area, perhaps the organisms are dead, they may even be museum specimens or fossils, perhaps they are both of the same sex (reproduce asexually), morphological differences are easier to determine, perhaps the biologist making the decision does not have the time or the facilities to attempt to interbreed them, so not possible to observe reproductive behavior, perhaps the organisms will not breed in captivity
• Binomial naming system


  Genus (generic name), species (specific epithet / trivial name), capital letter, Genus is one word, Species name is both words
• Domains of living organisms


  • Eukarya (Animals, Plants, Fungi, Protoctista)
  • Archaea
  • Bacteria
• Archaea


  • No nucleus, nuclear envelope, DNA exist as circular chromosome with histone proteins associated with DNA, have plasmids, cell membrane composition different from bacteria & eukarya, no membrane bound organelles, 70 S ribosomes but with features similar to that in eukaryotic ribosomes, not to bacterial ribosomes, cell wall present but doesn't contain peptidoglycan, cell divide by binary fission, unicellular, are extremophiles
• Eukarya


  • Cells have nucleus, cells contain membrane bound organelles, have large ribosomes 80S in cytoplasm, have 70S in mitochondria and chloroplast, chloroplast and mitochondrial DNA is circular as prokaryotes, DNA is arranged as linear chromosomes, with histone proteins, have cytoskeleton / cilia, cell division by mitosis, reproduce in different ways sexually or asexually, a great diversity of forms: unicellular, colonial and multicellular organisms
• Protoctista


  • Eukaryotic (having nucleus, linear DNA, chromosomes associated with DNA, membrane bound organelles, 80S ribosomes), mostly single-celled, or exist as groups of similar cells (multicellular), motile / unable to move, some have animal-like cells (no cell wall) and are sometimes known as protozoa, others have plant-like cells (with cellulose cell walls and chloroplasts) and are sometimes known as algae, have vacuole or no vacuole
• Fungi


  • Eukaryotic, do not have chlorophyll and do not photosynthesise, heterotrophic nutrition – they use organic compounds made by other organisms as their source of energy and source of molecules for metabolism, reproduce by means of spores, simple body form, which may be unicellular or made up of long threads called hyphae (with or without cross walls), large fungi such as mushrooms produce large compacted masses of hyphae known as 'fruiting bodies' to release spores, cells have cell walls made of chitin or other substances, not cellulose, never have cilia or flagella
• Plantae


  • Multicellular eukaryotes with cells that are differentiated to form tissues and organs, few types of specialised cells, some cells have chloroplasts and photosynthesise, cells have large, often permanent vacuoles for support, autotrophic nutrition, cell walls are always present and are made of cellulose, cells may occasionally have flagella – for example, male gametes in ferns, have starch stored compounds, have plasmodesmata
• Comparison of key features across kingdoms


  • Type of body
  • Cell wall
  • Cell vacuole
  • Cilia and flagellum
  • Motility
  • Nervous coordination
  • Nutrition
• Endemism


  A species that is native and restricted to a particular geographic location
• Ecosystem


  A self-sustained unit made up of biotic (living) and abiotic (non-living) components interacting and functioning together, includes the community of living organisms (biotic) in an area with abiotic factors (physical and chemical) factors linked by energy flow and cycling of nutrients
• Habitat


  A place where species lives with an ecosystem to provide them with food, shelter and breeding site
• Niche


  Role of living organism in an ecosystem and how this organism interacts with its environment (include type of food it eats (way of obtaining energy), where it lives, where it reproduces, and relationship with other species)
• Biodiversity


  Species diversity + genetic diversity + habitat diversity
• Measures of biodiversity


  • Variation in habitat (aquatic and terrestrial)
  • The number of different species in the ecosystem (species richness)
  • The relative abundance of species (evenness in distribution of species)
  • The genetic variation / diversity within each species
• Higher relative species abundance leads to greater species evenness, which indicates greater biodiversity
• Factors that determine the way of life of an organism


  • Way of obtaining energy
  • Where it lives
  • Where it reproduces
  • Relationship with other species
• Ways to measure biodiversity of an area


  • Variation in habitat (aquatic and terrestrial)
  • The number of different species in the ecosystem (species richness)
  • The relative abundance of species (evenness in distribution of species)
• Species richness


  The number of different species in the ecosystem
• Uneven species abundance


  When some species have much higher relative abundance than others
• Genetic diversity


  The genetic variation/diversity within each species, especially in case of high species abundance/large population
• Species richness


  Species abundance
• Species abundance


  Genetic diversity
• Gene pool


  The total genetic information in a population
• Evenness of distribution


  The relative abundance of different species
• Endemism


  Species that evolve in geographical isolation and are found only in one place
• Characteristics of areas with high endemism


  • Rich in biodiversity in terms of species richness (number of species)
  • Low biodiversity in terms of species abundance and low genetic diversity
• Effects of low genetic diversity in endemic species


  • Inbreeding depression
  • Less able to adapt to new environmental conditions
  • Higher chance of faulty alleles coding for diseases being expressed
  • Loss of hybrid vigour
  • Increased homozygosity
• How variation in different factors contributes to biodiversity


  • Variation in ecosystem/habitat
  • Variation in species diversity
  • Variation in genetic diversity
• How variation in ecosystem/habitat contributes to biodiversity


  • Different habitats
  • Different niches
  • Many different species
  • Genetic diversity within a species
  • Different selection pressures allowing adaptation to new environmental conditions
• How variation in species diversity contributes to biodiversity


  • Species richness (number of species in a habitat)
  • Relative species abundance (with greater species evenness)
• How variation in genetic diversity contributes to biodiversity


  • Increases heterozygosity
  • Decreases chance of harmful recessive alleles coming together
  • Decreases inbreeding depression
  • Increases hybrid vigour
  • Allows organisms to better adapt to new/changing environmental conditions
  • Increases survival chance
• Techniques for assessing species diversity


  • Random sampling
  • Simpson index
  • Mark-release-recapture
  • Belt transect
• Random sampling using quadrats


  1. Lay out two long tape measures at right angles

  2. Use random numbers to determine quadrat locations

  3. Place quadrats at intersections

  4. Measure species frequency, density, and percentage cover
• Abundance


  The number of organisms of a certain species in a certain area
• Distribution


  Where a species is located within a certain area
• Density


  Number of organisms per unit area