Distribution of organisms Flashcards
What is meant by a niche?
Every organism has its own niche i.e. the role an organism plays within a community. This includes the resources it requires in its ecosystem, such as temperature, light and nutrient availability and its interactions with other organism e.g. competition and predation, in the community. Therefore interactions with other organisms and levels of particular resources can influence where organisms live (their distribution) and how many of them there are (biodiversity).
What are the factors which can affect an organisms distribution?
Biotic factors and abiotic factors.
What are biotic factors?
Biotic factors are living things that affect the distribution of organisms e.g. competition for recourses, grazing, predation, food availability and disease.
What are abiotic factors?
Abiotic factors are non-living things which effect the distrubution of organisms e.g. temperature, humidity, pH and light intensity.
What are the five biotic factors affecting an organism’s distribution?
Competition for resources Predation Disease Grazing Food availability
What is competition?
Competition is the struggle between individuals when recourses are in short supply/limited e.g. food, light, water etc.
What are the effects of competition on an organisms distribution?
The effects of competition include more successful species increasing in number and less successful species decreasing in number.
What is meant by predation and how does it affect an organisms distribution?
A predator is an animal that hunts and eats other organisms therefore it can influence where particular prey live and ultimately the biodiversity of an ecosystem.
Which population is greater: Prey or Predator.
The population of predators always lags behind the population of prey.
What is the affect of predation on biodiversity?
Predation can increase biodiversity.
Why is disease a biotic factor?
It is a biotic factor because diseases are caused by living microorganism.
What is the affect of disease on an organisms distribution?
Disease has a similar effect to predation, controlling the number of organisms in a population.
Describe low levels of grazing.
At low levels of grazing, the slower-growing plant species die because they are out competed for recources by a small number of vigorous grass species which will then dominate the habitat. (Interspecific competition).
Describe intermediate levels of grazing.
At intermediate grazing levels some of the vigorous growing plants are eaten allowing the slower growing species to gain more of the resources to survive. Intermediate grazing levels therefore results in a mixture of slower and more vigorous growing plant species so increasing biodiversity.
Describe high levels of grazing.
At the high grazing levels, over grazing could damage all of the plant species present and very few grow.
Describe how food availability can affect the distribution of an organism.
Food availability can involve the availability of edible vegetation, eaten by herbivores, or it can involve the availability of prey, eaten by predators.
Name 5 abiotic factors.
These are the climate/environmental factors which can effect where an organism lives (distribution): Light intensity Temperature Soil moisture pH humidity
What measurement instrument can measure the abiotic factor:soil pH?
pH meter
What measurement instrument is used to measure the abiotic factor: Light intensity?
Light meter
What measurement instrument can be used to measure the abiotic factor: Temperature?
Thermometer
What measurement instrument can be used to measure the abiotic factor: soil moisture?
Soil moisture meter.
What measurement instrument can be used to measure the abiotic factor: Oxygen concentration?
Oxygen meter