unit b ecosystems and population change
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Unit B Ecosystems and Population Change. Ecosystems and their Diversity. Studying Ecosystems. Ecosystem Community of populations together with its abiotic and biotic factors that surround and affect it Small (lichen covered boulder on a hill side) or large (hill side)

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unit b ecosystems and population change

Unit B Ecosystems and Population Change

Ecosystems and their Diversity

studying ecosystems
Studying Ecosystems
  • Ecosystem
    • Community of populations together with its abiotic and biotic factors that surround and affect it
    • Small (lichen covered boulder on a hill side) or large (hill side)
    • Aquatic and terrestrial
transition between ecosystems
Transition between Ecosystems
  • Ecotone
    • grey area between ecosystems
    • Transition area where organisms from both ecosystems interact
    • Lots of species diversity in this region




types of ecosystems
Types of Ecosystems
  • Artificial Ecosystems
    • Living community is planned or maintained by humans
    • School yard, local parks, farms, managed forests
  • Natural Ecosystems
    • Living community is free to interact with physical and chemical environment
    • not untouched just not planned or maintained by humans
    • Lakes, rivers, forests, deserts, meadows
terrestrial and aquatic ecosystems in canada
Terrestrial and Aquatic Ecosystems in Canada
  • Canada has:
    • 2 major Aquatic biomes
      • Freshwater
      • Salt water/marine
    • 4 major Terrestrial biomes
      • Taiga (most)
      • Tundra (north)
      • Temperate Deciduous Forest (great lakes)
      • Grasslands (prairies)
terrestrial and aquatic ecosystems in alberta
Terrestrial and Aquatic Ecosystems in Alberta
  • Alberta’s aquatic ecosystems fit into the freshwater
    • Lakes, rivers, streams, ponds etc
  • Alberta’s terrestrial ecosystems fit into the Taiga and grassland biomes
    • Taiga (boreal forest)
    • Muskeg (bogs in boreal forest)
    • Grassland
    • Parkland, Foothills (ecotones)
    • Deciduous
who s who and what s what
Who’s Who and What’s What
  • Use the table of some of abiotic and biotic factors found in the four major ecosystems of Alberta
  • Take a piece of chart paper and divide the paper into four quarters and label appropriately
  • Place each factor in the quarter where you think it belongs be sure to justify
  • When finished give a brief description of each ecosystem
  • A group of organisms of one species that interbreed and live in the same place at the same time (e.g. deer population).
studying populations in ecosystems
Studying Populations in Ecosystems
  • Ecologists sample random populations within ecosystems to collect data that helps them better understand the species
    • Sampling Populations
      • Count species of a few samples of entire population then average them
      • Transects
      • Quadrants
features of populations
Features of Populations

Populations have a number of attributes that may be of interest to ecologists and we that we can measure during sampling:

  • Migration
  • Distribution and Abundance
  • Composition
  • Dynamics
  • Movement of individuals into (immigration) and out (emigration) of population
  • Affects density, distribution, dynamics and composition of a population
population distribution and abundance
Population Distribution and Abundance

Tells us more about the numbers of the pop

  • Density-# of organism per unit area (avg number of individuals per quadrant and dividing by size of quadrant) Total abundance can be determined from this
  • Distribution-Location of individuals within an area (random, clumped or uniform)
  • Carrying Capacity-max # of individuals that can be supported
population composition
Population Composition

Data that enables up to determine whether the pop is declining or increasing

  • Sex ratios-# of organisms of each sex
  • Population fertility-reproductive capacity of the females
  • Age structure-# of organisms of different ages
  • Capacity for survival-# of offspring that reach reproductive age
  • Length of reproductive life-age of sexual maturity & # of years the individual can reproduce
biotic potential
Biotic Potential
  • What is it?
population dynamics
Population Dynamics

Information that helps us understand what is happening within the pop

  • Growth Rate-change in the total population per unit time
  • Birth Rate- # of organisms born per unit time
  • Mortality Rate- # of organisms dying per unit time
  • Breeding Frequency-# of times that a organism reproduces each year
  • Birth Potential- # of offspring per birth
studying individual organisms in ecosystems
Studying Individual Organisms in Ecosystems

Ecologists study the following to find out more about specific species within a population:

  • Habitat and Range
  • Ecological Niche
  • Factors that limit growth
    • Abiotic and biotic factors
  • A place or area with a particular set of characteristics, both biotic & abiotic
  • Each species is found in a specific habitat that its physical, physiological and behavioural adaptations equip it to survive and reproduce
  • One large area or a bunch of small areas that are similar
  • Geographical area where the species is found
  • Species will only be found where its habitat is present
ecological niche
Ecological niche
  • Functional position of an organism in its environment, comprising of its habitat and resources obtained there, and the periods of time which its active
habitats and niches in ab ecosystems
Habitats and Niches in AB ecosystems
  • terrestrial and aquatic ecosystems can support a diversity of organisms because they have a variety of habitats and niches
  • Terrestrial Niches/habitats
  • Aquatic Niches/habitats



Forest floor

terrestrial niches habitats
Terrestrial Niches/Habitats
  • Canopy
    • Upper area of vegetation, lots of sunlight, diverse number of birds
  • Sub canopy
    • Usually shrubs and smaller trees, many browsers such as deer and moose
  • Forest floor
    • Lowest area, continuous shade, shelter nesting sites, supports many types of insects, shade loving plant
  • Soil
    • Temperature levels determine decomposition & organic matter
aquatic niches habitats lake
Aquatic Niches/Habitats (lake)
  • Littoral zone
    • Shallow, most productive part of the lake, plants and algae take full advantage of sunlight for photosynthesis
  • Limnetic zone
    • Enough light for photosynthesis to occur, plankton is the food for the higher level consumers
  • Profundal zone
    • Not enough light for photosynthesis, not alot of oxygen, carp and other invertebrates that can handle low o levels
  • Benthic zone
    • The :ground”, rooted and bottom dwelling organisms, amount of sunlight and temperature depend on depth of water
limiting factors
Limiting Factors
  • Abiotic and biotic conditions that limit the number of individuals
  • Species cannot grow in an unlimited fashion for a sustained period of time
  • Control the growth, distribution, survival of a species
  • Anything in short supply (e.g. nutrients or sunlight)
abiotic limiting factors
Abiotic Limiting Factors
  • Soil
    • Provides nutrients for all plants that grow on land
    • Determined by nature of rock in which it was formed, nature of plants & H2O acidity
  • Water (availability, depth of water table, pressure)
    • Organisms need water to survive
    • Determined by amount & type of ppt, how much collects then stays in soil, depth of water
    • Affects other abioitc and biotic factors
    • Vary throughout year
  • Sunlight
    • Provides energy to system
    • Depends on closeness to equator, seasons and location in ecosystem
  • Chemical Nutrients
    • Important to survival of organisms
    • Determined by seasons, soil, temperature, , amount dissolved
biotic limiting factors
Biotic Limiting Factors
  • Competition
    • Intraspecific= members of same population compete with each other for limited resource (food, water, sunlight, mates, shelter, breeding sites etc)
    • Interspecific= members of two different populations compete (exotic species) resulting in extinction of one or both of the populations
  • Predators
  • Parasitism=one organism (parasite) derives its nourishment from another organism (host) which is harmed in some way
classifying organisms
Classifying Organisms
  • Scientists use classification system to understand similarities and differences between species
  • Science of classifying =Taxonomy (Taxonomists)
levels of taxa
Levels of Taxa
  • 7 levels of classification
    • Kingdom
    • Phylum
    • Class
    • Order
    • Family
    • Genus
    • Species
6 kingdoms
6 Kingdoms
  • Eubacteria
  • Archaebacteria
  • Protista
  • Fungi
  • Plantae
  • Animalia
binomial nomenclature
Binomial Nomenclature
  • Developed by Carl Linneaus as a way to scientifically name and classify organisms
  • Based on physical and structural features (anatomy, embryology, and ancestry)
  • More features in common the closer the relation
  • 2 part name (usually Latin)
    • Genus species
using a dichotomous key
Using a Dichotomous Key
  • Classification manuals that are constructed to help conduct their identification work
  • A series of choices about the structure of the organisms must be made and each choice leads to a new branch
  • If each choice is made correctly then the end result will be the organisms name