Biodiversity, classification and conservation (Revision 1)

Biodiverisity

Classification

Conservation

Taxonomic hierarchy

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Characteristic features of the 3 domains

Bacteria:


  • cells have no nucleus
  • DNA exists as a small 'circular chromosome' & doesn't have histone proteins associated with it
  • plasmid DNA
  • no membrane bound organelles (mitochondria, endoplasmic reticulum, Golgi body, chloroplasts)
  • 70S ribosomes (smaller than in eukaryotic cells)
  • peptidoglycan cell wall
  • cells divide by binary fission
  • usually exist as single cells or small groups of cells

Archaea:


  • cells have no nucleus
  • DNA exists as a small 'circular chromosome' & doesn't have histone proteins associated with it
  • plasmid DNA
  • no membrane bound organelles
  • 70S ribosomes smaller than in eukaryotic cells but they have features similar to eukaryotic ribosomes not bacterial ribosomes
  • cell wall
  • cells divide by binary fission
  • usually exist as single cells or small groups of cells

Eukarya:


  • have nucleus + membrane bound organelles
  • DNA in the nucleus arranged as linear chromosomes w/ histone proteins
  • 80S ribosomes (larger than prokaryotes)
  • chloroplast and mitochondrial DNA is circular
  • diversity or forms: unicellular, colonial & multicellular
  • cell division by mitosis
  • can reproduce asexually and sexually

Archaea and Bacteria are prokaryotes

Characteristic features of the kingdoms

Protoctista


  • eukaryotic
  • mostly single-celled
  • some have animal-like cells (no cell wall) + are sometimes known as protozoa
  • others have plant-like cells (w/ cellulose cell walls + chloroplasts) + are sometimes known as algae

Fungi


  • eukaryotic
  • no chloroplasts + don't photosynthesise
  • heterotrophic - they use organic compounds made by other dead organisms
  • reproduce by spores
  • unicellular or made up of long threads (hyphae)
  • chitin cell walls
  • never have cilia/flagella

Plantae


  • multicellular eukaryotes w/ cells that are differentiated to form tissues and organs
  • few types of specialised cells
  • chloroplasts & photosynthesise
  • autotrophic
  • cellulose cell walls
  • cells may have flagella

Animalia


  • multicellular eukaryotes w/ cells that are differentiated to form tissues and organs
  • many types of specialised cells
  • no cell walls
  • some cells have cilia/flagella
  • communication is by the nervous system
  • small and temporary cell vacuoles
  • heterotrophic

Viruses

Why are viruses not included in the 3 domain classification and how are they classified?


Their taxonomic system is based on the type of nucleic acid they contain (DNA or RNA), and whether the nucleic acid is single-stranded or double-stranded

5 major threats to biodiversity


  • habitat loss and degradation of the environment
  • climate change
  • excessive use of fertilisers & industrial and domestic forms of pollution
  • overexploitation and unsustainable use of resources
  • the effects of alien (invasive) species

Reasons for the need to maintain biodiversity


  • Maintains genetic variation
  • Economic value
  • Cultural value
  • Scientific value - species can be used to make medicine
  • Recreational value
  • Prevents extinction
  • Aesthetic reasons

Methods of protecting endangered species

Methods of assisted reproduction

IVF

Artificial Insemination

Seed banks

Frozen zoos

Botanic gardens

Conserved areas (national parks)

Embryo transfer

Zoos - captive breeding programmes

Methods to prevent the overpopulation of species

Culling

Cutting male mammals' sperm ducts

Chemical contraceptives for female mammals

Reasons for controlling alien/invasive species


  • Because they'll compete with native species for food
  • Because they'll outcompete native species by reducing the space in which they can grow
  • Because they introduce diseases and spread them to native organisms that have never been exposed to the pathogens

How may degraded habitats be restored?


  • farmers may decide to plant trees on land that is no longer needed for food production
  • replanting mangrove forests which reduce coastal erosion by reducing the effects of strong waves during storms & act as a barrier against rising sea levels by trapping sediment & are nurseries for young fish
  • tree planting projects by NGOs
  • reclamation projects

Random sampling


Throw the quadrat randomly and record the number of individuals and the number of species


Throw the quadrat a few other times

Systematic sampling

Line transect


  • Randomly select a starting point in a field and flat out a measuring tape in a straight line
  • Note the type of organism found at regular points along the line

Interrupted belt transect


  • Randomly select a starting point in a field and flat out a measuring tape in a straight
    line
  • Record the abundance of organisms regular intervals

Mark-release-recapture

  1. Capture the species
  2. Each individual is marked
  3. The marked individuals are counted and released back into their habitat
  4. When enough time has passed, another large sample is captured
  5. The # of marked and unmarked individuals are counted

A way of estimating the population size

Limitations:

The 3 levels of biodiversity


  • The variation in ecosystems or habitats
  • The # of different species in the ecosystem and their relative abundance
  • The genetic variation within each species