Ecosystems Flashcards
What do living organisms do in order to survive and reproduce!
Interact with other organisms and the environment in which they live
What is an environment?
The sum total of the biological, physical and chemical conditions surrounding an organism
What is an ecosystem?
A particular area in which living components interact with one another and with non-living components
What is another name for the living components in an ecosystem?
Biotic
What is another name for the non-living components in an ecosystem?
Abiotic
What is the size of an ecosystem?
It can be a giant rainforest, or a tiny drop of water
What is ecology?
The study of relationships and interactions between living organisms and between the organism and the natural environment in which they occur
How many abiotic factors are there?
Seven
What are the seven abiotic factors?
Physiographic Edaphic Light Temperature Water Atmospheric gases Wind
What are the climatic factors?
The collective term for wind, temperature, light, water and atmospheric gases
What are three physiographic factors?
Aspect
Slope
Height above sea level
What is aspect?
Slope direction
It refers to the position of an area in relation to the sun
How does aspect influence vegetation?
One side of a slope gets more sunlight than another
Sun-loving vegetation therefore prefers this slope
Shade plants prefer the other side
Which side of a mountain (in SA) gets more sunlight?
North
What is slope?
How steep or flat a landscape is
What does slope affect?
The rate of water run-off
How does the rate of water run-off affect vegetation?
More run-off means more nutrients are washed away
There are fewer nutrients available
Few plants and animals are present
What kind of slope increases the rate of water run-off?
Steep
What kind of slope decreases water run-off?
Gentle
What kind of weather can be found high above sea level?
Extreme
Strong winds
Snow
What are edaphic factors?
Soil factors
What are five edaphic factors?
Type of soil Soil air Water-holding capacity Humus content pH
What are the three types of soil?
Clay
Loam
Sand
What kinds of particles are found in clay?
Tiny
What kinds of particles are found in loam?
Slightly larger particles
What kinds of particles are found in sandy soil?
Coarse, large particles
What is soil texture?
It refers to how coarse or fine the soil is
What is soil air?
Spaces between soil particles that are filled with air
Why is soil air important?
It is vital for the survival of soil organisms
Which type of soil has the most soil air?
Sandy soil
When soil has soil air, what is it referred to as?
Well-aerated soil
Why is soil air important for plants?
The pockets of soil air allow space for plant roots to push through
What is water-holding capacity?
How much water is retained in the soil
Which type of soil has the greatest water-holding capacity?
Clay
Why does clay have the best water holding capacity?
The tiny particles are close together, trapping the water
What happens when soil (such as sand) has a low water-holding capacity?
The water drains through the soil
What is leaching?
Leaching occurs when water drains through soil and takes nutrients with it
Why isn’t clay soil suitable for pant growth, even though it has a great water-holding capacity?
The plant roots rot because the water does not drain away
What type of soil is the most suitable for plant growth?
Loam
Why is loam suitable for plant growth?
Sufficiently aerated
Has a good water-holding capacity, but it can still drain
It contains sufficient nutrients
What is humus?
Decayed plant and animal matter
Why is humus good in soil?
It increases the available nutrients in soil
Increases the soil’s water-holding capacity
What is soil with sufficient nutrients in it called?
Fertile soil
What colour is soil with a high humus content?
Dark brown
How does pH affect plant growth?
Different plants prefer different pH
Which plants prefer acidic soil?
Azaleas
Proteas
Which plants prefer alkaline soil?
Succulents
What kind of pH do most plants prefer?
Neutral (7)
How does leaching affect pH?
Leaching causes the soil to become acidic
Where does leaching often occur?
In high rainfall regions with sandy soil
Why do plants need light?
For photosynthesis
Why can excessive light be detrimental to plants?
It can damage tissues
What is day length?
The duration of time that plants are exposed to light
What is photoperiodism?
The effect of day length on the growth of the plant