Part 1 (new)

• What is biodiversity?

  Variety of life and habitats
• What contributes to genetic biodiversity?

  Mutations within species
• What is a habitat?

  Place where an organism lives
• What defines a population?

  Group of the same species in one habitat
• What is a community in ecological terms?

  All populations of different species in a habitat
• How are species defined?

  Similar organisms that can interbreed
• What is an ecosystem?

  Area including biotic and abiotic components
• What are the components of an ecosystem?

  Biotic and abiotic components
• How do populations and communities differ in ecology?

  Populations are same species, communities are different species
• If a new species is introduced to a habitat, what ecological concept does this affect?

  Community dynamics
• NICHE


  role of an organism/species in its environment/ecosystem

  • position in food web
  • each species interacts/responds differently to resources, environment and other species, thus has a unique niche
  • MORE DIVERSITY=MORE NICHES
• levels of biodiversity


  HABITAT

  SPECIES

  GENETIC
• HABITAT BIODIVERSITY


  number of different habitats in an area - meadow/sand dune/tree canopy

  each habitat can support a number of different species

  MORE SPECIES=MORE AVAILABLE NICHES=GREATER HABITAT BIODIVERSITY

  EXAMPLE

  • trees have different niches at different heights so provide different habitats with slightly different conditions
• SPECIES BIODIVERSITY


  species richness - the number of different species living in a particular area

  species evenness - the relative abundance of each species living in an area

  AN AREA CAN HAVE THE SAME NUMBER OF SPECIES BUT STILL DIFFER IN SPECIES BIODIVERSITY

  • more biodiverse as greater SR and greater SE as individual organisms are more spread out
  • less biodiverse as area is dominated by ___
• genetic biodiversity


  genetic variation within a species due to different alleles

  ALLELES - different versions of the same gene leading to physical and behavioural variation

  GENETIC BIODIVERSITY covers genetic variation within distinct populations of the same species and within a single population
• GREATER GENETIC BIODIVERSITY LEADS TO INCREASED CHANCE OF A SPECIES SURVIVING LONG TERM


  • greater range of alleles
  • greater chance organism will be able to survive a change in habitat

  EXAMPLES

  • individual may be resistant to a new disease so less likely to be killed by disease
  • individuals may be better adapted to catch new prey or avoid new predators, so respectively less likely to die from hunting or starvation
• WHY CAN NUMBER OF SPECIES ONLY BE ESTIMATED

  • new species constantly being found
  • endangered species and extinctions
  • speciation and evolution continuing - new species being created~
• stability of high and low BD


  HIGH

  • change in environment (human impact, new disease/pred) affects only one species, which is a small proportion of total number of organisms
  • small impact on entire habitat
  • habitat can withstand change

  LOW

  • habitat dominated by FEW species
  • change in environment affects this one species, which is a larger proportion of total number of organisms
  • large impact on entire habitat, which may not be able to recover from change
• low biodiversity/high biodiversity

  LOW

  • few successful species
  • harsh environment
  • few species live in habitat and many have specific adaptations
  • simple food web
  • large impact on environment if change

  HIGH

  • many successful species
  • less harsh environment
  • many species live in habitat, few have specific adaptations
  • complex food web
  • change in environment has small impact
• WHY DO HUMANS HAVE MANY SAME GENES AS PLANTS


  • plants have same basic structure and organelles
  • plants use same enzymes for protein synthesis and ribosomes
• WHY SAMPLING

  • habitats too large and too many organisms
  • sampling quicker and representative
  • impractical to count all organisms in an area
  • instead sample a small area and multiply the numbers found in the small area by the entire habitat
• KEY IDEAS

  • taking measurements of a limited number of individuals in an area, allowing the measurement of the number of organisms in an area without having to count them all
  • ABUNDANCE - number of individuals in a species in an area
  • allows estimate of number of organisms, distribution of species or measured characteristics
• why random sampling


  allows sample to not be biased and representative of entire area

  prevents over/underestimate of diversity

  • random number generator/number table
• HOW MANY SPECIES SAMPLED?


  the bigger number used, the more representative

  HOWEVER

  • time can be an issue
  • diversity of a habitat may be limited
  • no new species found
• QUADRAT

  used to measure plants and immobile species

  frame than forms a known area, and used to measure DENSITY, FREQUENCY, PERCENTAGE COVER

  • assumed that contents within the quadrats are representative of entire sampling area
  • smaller quadrats used to measure distribution of lichens and trunk moss
• DENSITY


  count the number of individual organisms in a 1x1 m quadrat which gives density per square meter

  this is an ABSOLUTE MEASURE, not an estimate
• PERCENTAGE FREQUENCY


  the proportion of quadrats that contain a particular species

  used when individual members of a particular species are hard to count (grass)

  NUMBER OF Q CONTAINING SPECIES/TOTAL QUADRATS
• PERCENTAGE COVER


  visual estimate of the area within a quadrat that a particular species covers

  if more than half square covered, count - if not, don't count

  USED

  • speed
  • when a particular species is abundant/hard to count
• POINT QUADRAT


  • apparatus consists of a free-standing frame with a row of ten sliding pins
  • frame lowered into vegetation
  • record is kept of pin number and number of different species touching that pin
• ACFOR SCALE


  measure of species abundance

  A - abundant 30%+

  C - common 20-29%

  F - frequent 10-19%

  O - occasional 5-9%

  R - rare 1-4%
• METHOD OF RANDOM SAMPLING


  • place 2 tape measures at right angles along the side of study area
  • obtain 2 coordinates using random number generator (if site large, use map and GP)
  • place top left of quadrat against the coordinates - hard to judge position of coordinates and ensures positioning is unbiased + accurate
  • key to identify species, estimate %cover/ACFOR scale
  • repeat at least 5 times + calculate mean
  • repeat during different times of year
• SIMPSON'S INDEX OF DIVERSITY


  measure of biodiversity

  NEED

  • number of individuals in a species in an area
  • number of species in an area

  BETTER MEASURE THAN JUST COUNTING

  • takes into account the number of species in an area
  • takes into account the number of individuals of a species in an area

  GREATER VALUE=MORE STABLE=MORE DIVERSE HABITAT
• what do values represent


  N - number of organisms (species richness)

  n - number of each species (used to determine species evenness)
• OPPORTUNISTIC SAMPLING


  • using organisms that are readily available
  • weakest form of sampling as not representative of entire population
• STRATIFIED SAMPLE


  a population is divided into sub groups (strata) based on a particular characteristic

  random sample then done on each subgroup-proportional to size

  reduced bias in results
• SYSTEMATIC SAMPLING


  used to measure changes across an area - DISTRIBUTION OF PLANT SPECIES

  usually use a line or belt transect

  RANDOM SAMPLING NOT USED but as long as method isn't changed to suit area, biased results should not be generated

  LINE TRANSECT

  • line along an area and samples taken at specified points - DESCRIBING ORGANISMS TOUCHING THE LINE OR DISTANCE SAMPLE IS FROM LINE

  BELT TRANSECT

  • mark two parallel lines and samples taken from area between the lines
• INTERRUPTED LINE TRANSECT


  • SYSTEMATIC - quadrats not placed at random but at regular intervals
  • used to show how communities are distributed along a gradient, which could be a slope or abiotic feature change - QUALITIATIVE

  LINE TRANSECT

  • place tape measure along study site
  • at regular intervals, record species touching the line
  • use a key to identify species
  • repeat many times and repeat in one area
• BELT TRANSECT


  • belt transect
  • place two tape measures along study site
  • at every part of transect line (CONTINUOUS)/at regular intervals (INTERRUPTED) place quadrat between lines and estimate %cover/ACFOR scale
  • use key to identify species
  • repeat sampling over time and in one area
• sampling mobile species


  pitfall trap

  sweepnetting

  pooter
• PITFALL TRAP


  used to measure small, crawling invertebrates (spiders)

  trap deep enough so they can't fall out, but roof structure propped up so that it doesn't fill with water