Topic 2 – The Ecosystem 2.1 - Structure IB Topics 2.1.1-2.1.7

Key Words (define and provide a local example of each) Biotic Species Abiotic Population Trophic Level Community Producer Habitat Consumer Ecosystem Autotroph Niche Heterotroph Competition Carnivore Mutualism Herbivore Parasitism Omnivore Predation

Biotic and Abiotic Components All living components of the ecosystem Ex: All non-living components of the ecosystem Ex:

Food Chains The position an organism occupies in a food chain is called the trophic level.

Local Food Chain Example: Make your own food chain with Wisconsin species.

Food Webs Ecosystems contain many interconnected food chains

Pyramid of Numbers A graphical model of the number of organisms in a food chain

Pyramid of Biomass A graphical model of the amount of biomass present in a food chain at a certain point in time ***Discuss how biomass is calculated and if its ethical***

Pyramid of Productivity A graphical model of the rate of energy production over time

Top Carnivores Bioaccumulation Biomagnification Toxins (pesticides, etc.) can be retained in fat tissue Each successive trophic level gains more toxin

2.2 – Measuring Abiotic Components Topic 2 – The Ecosystem 2.2 – Measuring Abiotic Components IB Topics 2.2.1-2.2.2

Significant Abiotic Factors Terrestrial Ecosystem Includes: land Temperature Light intensity Wind speed SOIL particle size moisture drainage mineral content Marine Ecosystem Includes: Oceans, estuaries, salt marshes and mangroves salinity temperature wave action dissolved oxygen pH Freshwater Ecosystem Includes: lakes, rivers, streams, wetlands turbidity temperature flow velocity pH dissolved oxygen

2.3 – Measuring Biotic Components Topic 2 – The Ecosystem 2.3 – Measuring Biotic Components IB Topics 2.3.1-2.3.5

Estimating abundance of organisms Counting the number of organisms is almost always done using an estimate

Lincoln Index A mathematical model to estimate population size Capture-mark-release-recapture

Example 1 Example 2 13 deer were caught and marked 14 deer were caught the second time and 5 were marked 75 Ladybugs were caught and marked 80 Ladybugs were caught the second time and 3 were marked

Quadrats A square of area used to measure the population of non-mobile organisms Can help to calculate population density and percentage cover

Diversity The number of different species The number of individuals of each species

Simpson’s Diversity Index Used to compare diversity between areas High value of D implies stable ecosystem Low value of D implies unstable ecosystem

Topic 2 – The Ecosystem 2.4 – Biomes IB Topics 2.4.1-2.4.2

Biomes A collection of ecosystems that share similar climactic conditions

Rainforest Desert Tundra Temperate Forest Grassland Prevailing Climate Location Sun Exposure Precipitation Limiting Factors

Varied, where some precip Rainforest Desert Tundra Temperate Forest Grassland Prevailing Climate Hot, Humid, Rainy Hot, Dry Cold Seasonal Varied by location Location Near Equator Varied, where no precip Poles 40-60o N Latitude Varied, where some precip Sun Exposure High Varied, usually high Low Medium, Seasonal Varied Precipitation None Snow Limiting Factors Too much precip. Not enough water Too cold, permafrost Seasons Low precip

Topic 2 – The Ecosystem 2.5 – Function IB Topics 2.5.1-2.5.7

Photosynthesis

Respiration

Energy Flow Through the Ecosystem

Gross Primary Productivity (GPP) The amount of energy produced by producers

Net Primary Productivity (NPP) The amount of energy stored by producers and available to consumers

Gross Secondary Productivity (GSP) The amount of energy consumed by consumers

Net Secondary Productivity (NSP) The amount of energy stored by consumers and available to the next trophic level

Simplified Example:

Topic 2 – The Ecosystem 2.6 – Changes IB Topics 2.6.1-2.6.7

Carrying Capacity The maximum number of organisms an ecosystem can support sustainably over a long period of time

Limiting Factors Factors that limit the amount of individuals in an ecosystem

Tolerance Species will be most abundant within a certain range of a limiting factor

Population Curves S Curve J Curve Reaches carrying capacity and stabilizes J Curve Unchecked population growth

Limiting Factors Density-dependent factors Limit population size more as population increases

Limiting Factors Density-independent factors Limit population size regardless of population size

K-strategists r-strategists C-strategists Opportunistic species Inhabit unstable/changing environments Reproduce early/often, mature quickly Slow growing/maturing species Few offspring Long lifespans C-strategists In between r & K

Survivorship Curve

Succession A natural increase in the complexity of the structure and species composition over time

Succession Primary Secondary Occurs where a previous community has been destroyed Occurs on uncolonized substrate (rock)

Zonation Different types of ecosystems in a gradient due to elevation or resources Ex: Altitude zonation on a mountain

Climax Community A stable, complex ecosystem in a late stage of succession Characteristics:

Topic 2 – The Ecosystem 2.7 – Measuring Changes IB Topics 2.7.1-2.7.3

Environmental Impact Assessment Before any development gets permission to begin, an EIA must be done Predicts the potential impacts on habitats, species, and ecosystems

Baseline Study Habitat type Species list Species diversity Endangered species Land use Hydrology Human population Soil quality