Summary Biology 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 14.1, 14.2, 14.3, 14.4, 14. 5
13.0 Ecology
Ecology = the study of ecosystems
Ecosystem = an area of all the biotic and abiotic factors.
13.1 What is ecology?
Abiotic factors = factors that are non-living (stone, water)
Biotic factors = factors that are alive or dead (animals, dead plants)
Environmental factors = factors in nature where organisms depend on; abiotic and biotic
Environmental problems = problems in nature such as deforestation, climate change and
overfishing
Sustainable use = use of nature where future-generations also benefit from a well-managed
environment.
The environment influences organisms in a certain area by abiotic and biotic factors. When
there are for example a lot of mice in an area, owls will have a nice time, and the other way
around. Also when there is a lot of water for example, there will be more animals and plants
than when there is no water available.
Ecologists are people who study ecosystems, and develop solutions for environmental
problems.
An ecosystem is made out of the biotic and abiotic factors.
13.2 The distribution of organisms
Brackish water areas = a coastal area where freshwater from rivers is mixed with slaty
seawater. Brackish water is less salty.
Coastal zone = the area near land, where the water is not deeper than 20 meters
Margin of tolerance = between the min and max of abiotic factors of animals. (temperature,
other animals, water, etc)
Microclimate = the local values (temperature, light, wind, humidity) of the environmental
factors.
Optimum temperature = the temperature between the min and max temperature of an
organism; here the organism can function best.
Tolerance range = the minimum and maximum of abiotic factors for animals. The min and max
animals can handle.
, Vegetation zones = indicate which plant species can grow in the carious climate zones on earth.
(tropical forest, grasslands, desert, deciduous forest, evergreen forest, tundra, polar region)
Wetlands = when there is a lot of rain, the rivers go beyond their banks, these areas remain
marshy.
Tropical forest – very warm and humid with a lot of tropical plants.
Grasslands – an area with semi-high plants, often pretty vegetated and with lots of plants.
Desert – very warm and dry, with little animals and plants.
Deciduous forest – a forest where that shed their leaves in one season.
Evergreen forest – dense forest with a lot of trees, plants, creepers, etc. Always green colour;
the normal forest.
Tundra – very dry and often cold area, with low plants and little animals.
Polar region – very dry, cold area with a lot of ice and snow and little plants and animals
These vegetation zones have come about like this because of abiotic factors. Like wind, ice,
temperature, humidity, etc.
, An organism distributes in areas because of their traits. So a polar bear won’t go to warmer
places by itself. Environmental factors also play an huge role, they decide if an animal stays or
goes away.
The minimum tolerance of an animal is the things that they absolute need. The maximum
tolerance of an animal is the maximum of what the can handle. The tolerance range is in
between. And the optimum is the middle of these.
You can explain the similarities between the vegetation zones from north to south and from
high to low.
Seas are salt and rivers sweet. So you won’t find sweet water fish in the sea and vice versa. This
thus also determines the distribution of species.
Humans also play a major role in the distribution of species because they make cities and roads,
etc. If humans destroy a rainforest, the animals will flee.
13.3 Changes in numbers within population.
Limiting factor – the factor that restricts growth, lack of food.
Population pyramid – a graph of the age structure of a specie
Ecological balance – the same number of animals come and go.
Density independent factors – when the population of a specie is dependent on the amount of
the pray and predator.
Carrying capacity – the maximum that an ecosystem can handle.
Emigration – animals that leave a certain area.
Exponential growth – the rapid growth of a number.
Birth rate – the number of young born per year.
Immigration – Animals that arrive in a certain area.
Population structure – the structure between age and male and female.
Negative feedback – The decreasing and increasing of both the prey and predator.
Survival rate – The amount of babies that survive, more for mammals.
Survivorship curve – see picture
Population – the amount of organisms in a certain area.
Population density – Number of individuals per area or per volume.
Sampling – Estimating the population by taking the individuals per area and multiplying/dividing
this.
Mortality rate – Number of death per year.
Distribution patterns – 1. Clumped dispersion, a school of fish. 2. Uniform dispersion, penguin
nests are spaces at a certain distance. 3. Random desperation, the flowers in a field.
