Download Carrying Capacity PPT

Ecosystem Populations
Continued
http://www.whale-images.com/endangered-mammals-80-pictures.htm
Exponential Growth
Earths Human Population
Carrying Capacity
• It’s the largest
population of a species
that an environment
can support.
• Food supply, competition,
and predators can affect
population size.
http://www.rareconservation.org/blog/index.php?paged=2
• Seychelles Paradise Flycatcher
requiring about one hectare of
mixed woodland per breeding
pair. Lives on small island
north-east of Madagascar.
4 Limiting Factors that determine the
carrying capacity
1) MATERIALS AND ENERGY
• Limited by amount of energy from the Sun
• Supply of water, carbon and other materials
http://www.condorjourneysadventures.com/costarica_nature.asp
http://weathersavvy.com/Q-Climate_DesertsHot.html
4 factors that determine the carrying
capacity of an ecosystem
2) FOOD CHAINS
• Biomass in all levels affects the length of the chain.
• Limited by amount food supply (so trophic level
below)
• Limited by predators (so trophic level above)
4 factors that determine the
carrying capacity of an ecosystem
3. COMPETITION
• Competition for food, water,
mate and space.
• Intraspecific competition:
among members of the
same species
• Interspecific competition:
between species.
4 factors that determine the
carrying capacity of an
ecosystem
4) Population density :
How many individuals
that can live in an
area at one time.
Density-dependent factors
• When density increases
beyond suitable level:
• Overcrowding may :
– increase stress and
spread of diseases or
parasites
– Increase aggression and
neglect of offspring
• Therefore decreases
population
Density-independent factors
Limit a population regardless
of its size.
-Forest fire
-Earthquake
-Volcanic eruption
-Tornado
Feeding People
Productivity
• The average amounts of new plant
biomass produced each year per unit
area.
Productivity of ecosystems
• Productivity is influenced by many factors
Factors that can increase productivity
• Add water and fertilizer to deserts
• Very expensive
Factors that can increase productivity.
• Clear cutting rain
forest
• Introduce good farm
plants and animals
into rainforest
conditions.
• Not a good idea.
• Disease, pests,
weather fluctuations.
Food and Population Size
• Canadians consume more calories and
more animal products per day than
others in the world.
• 80% of the Earth’s population consumes
grains as primary source of nutrition.
Food and Compeitiors
• Natural ecosystem – hundreds of
species are interconnected.
• Agricultural – produces short, simple
food chains, that link plants to people.
Factors that increase productivity.
• Monoculture
• A single crop (wheat,
corn or rice) is often
grown on huge areas
of land.
• How does
monocultural affect
populations of primary
consumers?
Costs of monoculture – pests
This peel represents the surface, the
skin of the earth's crust, the topsoil
on which humanity depends. It's
less than 5 feet deep and can
produce only a fixed amount of
food. Due to erosion and overfarming, we lose 24 billion tons per
year. It takes 100 years for one
inch of topsoil to form