pyramid of numbers grass rabbit fox number decreases size increases
TRANSCRIPT
Pyramid Of Numbers
GRASS
RABBIT
FOX
Number decreases
Size increases
The Pyramid of BiomassA pyramid of biomass shows the total biomass at each stage of a food chain.
Biomass is the mass of all the organisms in that population.
Biomass goes down as you move along a food chain, so this gives a pyramid shape.
HOMEWORKSet Tues 28 August Due Fri 31 Aug
Biosphere Booklet
Questions 1 - 17
Population
The number of organisms of the same species present in an
ecosystem
What does the growth rate of a population depend on ?
• Birth rate is measured by counting the number of live births in a population during an interval of time
• Death rate is measured by the counting the number of deaths in a population during an interval of time
• The growth rate of a population depends on the birth and death rates.
Population Growth
Left unchecked a population will grow Exponentially!
This is called a ……
Population Explosion
Human Population Growth
The Human Race is undergoing a Population Explosion.
The growth curve of a population in ideal conditions continues to rise indefinitely because the birth rate is high and the death rate is low.
Factors Limiting Population Growth
Limiting Factors
Disease/Parasites
Predators
Starvation Abundance of Food
Predation Lack of Space
Natural Disasters
Competition
Plants compete for …•Light •Water •Nutrients
Animals compete for …•Food •Water •Shelter •Nesting Sites•Mates
Transparent Lid
Damp Cotton Wool
Radish Seeds Only
Cress Seeds Only
Radish and Cress Seeds
After 5 Days at 240C
Healthy Radish
Healthy Cress
Healthy Radish Sickly
Cress
If the competing individuals are of the same species their needs will be almost identical so the competition will be even more intense !
This results in the stronger more successful competitors surviving and the weaker competitors dying off.
The Nitrogen Cycle !
Nitrogen Gas
Nitrogen in Soil Nitrates
Nitrogen in Plants
Nitrogen in Animals
Death and Decay
Nitrogen in Ammonium Compounds
Nitrogen in Nitrites in Soil
Denitrification by Bacteria
Lightening!
NItRATES
Lightening
Fertiliser
Nitrogen Fixing Bacteria
Leaching
Cropping
Denitrifying Bacteria
Keeping It Balanced!
• Nitrogen Cycle QuestionsNitrogen Cycle Questions1.How much nitrogen gas is there in the air? (1)
2.How can nitrogen be removed from the air? (3)
3.How can nitrogen be added to the air? (1)
4.How can nitrogen be added to the soil? (4)
5.What happens to the nitrogen in the soil? (2)
6.What happens to the nitrogen in plant proteins? (2)
7.How does decay of organisms and their wastes add nitrogen to the soil? (3)
• ANSWER IN FULL SENTENCES