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Biodiversity, classification and conservation (Revision 1), Domain
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Biodiversity, classification and conservation (Revision 1)
Biodiverisity
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
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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
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Conservation
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
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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
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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
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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
- 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
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