b7: adaptations interdependence and competitiom

define ecosystem

the interaction of a community of biotic organisms with abiotic parts of their environment

what do plants compete for?

light

space

water

mineral ions

what do animals compete for?

food

shelter

mates

define interdependence

if one species in a community is removed, the whole community is affected

define a stable community

a community where all the species and environmental factors are in balance, so that population sizes remain fairly constant

what are abiotic factors that can affect a community?

1. light intensity

2. temperature

3. moisture levels

4. soil pH and mineral content

5. wind intensity and direction

6. carbon dioxide levels for plants

7. oxygen levels for aquatic animals

what are biotic factors that can addect a community?

1. availability of food

2. new predators

3. new pathogens

4. one species out competing another so the numbers are no longer sufficient to breed

what are extremophiles?

organisms that live in environments that are very extreme such as high temperatures, pressure or salt concentration

state the factors affecting the rate of decay.

1. temperature

2. water

3. oxygen

why do gardeners try to provide optimal conditions for rapid decay?

the compost produced is used as natural fertiliser for growing garden plants or crops

what does anaerobic decay produce?

methane gas

define biodiversity

the variety of all the different species of organisms on earth or within an ecosystem

what does a great biodiversity ensure?

that the stability of ecosystems by reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment

how do humans reduce the amount of space available for other animals and plants?

1. building

2. quarrying

3. farming

4. dumping waste

why has large-scale deforestation in tropical areas occurred?

1. to provide land to cattle and rice fields

2. to grow crops for biofuels

state the negative human interactions in an environment.

1. habitat destruction and fragmentation

2. pollution

3. climate change

state the positive human interaction in the environment

1. introducing breeding programmes to help endangered species

2. protection and development of new endangered habitats

3. replanting hedgegrows because there is high biodiversity in them

how can decomposers break down dead material?

by secreting enzymes into their environment. small soluble food molecules then diffuse into the microorganism

what are losses of biomass due to?

1. not all indigested material is absorbed dome is egested as faeces

2. some absorbed material is lost as waste, such as carbon dioxide and urea

define food security

having enough food to feed a population

state the biological factors threatening food security

1. the increasing birth rate

2. changing diets in developed countries means scare food resources are transported around the world

3. new pests and pathogens that affect farming