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
- Capture the species
- Each individual is marked
- The marked individuals are counted and released back into their habitat
- When enough time has passed, another large sample is captured
- 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