ESS EOYT

Topics: - 1 (all) - 2 (all) - 3 (all) - 4.1-4.2 - 5.1

Simpson’s Diversity Index

Simpson’s Diversity Index

a measure of diversity which takes into account the number of species present and the relative abundance of each species

Simpson’s Diversity Index formula

n = total number of organisms of a particular species
N = total number of organisms of all species

High values of D indicate a stable and ancient site
Low values of D indicate pollution, recent colonization or agricultural management

Standard deviation

T-test

tells you if you can trust your data

Biodiversity

The amount of biological or living diversity per unit area

Species diversity

The variety of species per unit area. Includes the number of species present and their relative abundance

Habitat diversity

The range of different habitats or number of ecological niches per unit area

Genetic diversity

The range of genetic material present

Threats towards biodiversity

• Natural hazards

• Loss of habitat

• Fragmentation of habitat

• Pollution

• Agricultural practices

• Overexploitation

• Non-native species

• Spread of disease

Factors used to determine conservation status

• Population size

• Reduction in population size

• Number of matured individuals

• Geographical range/degree of fragmentation

• Quality of habitat

Factors making species prone to extinction

• Limited distribution

• Small population size

• Habitat specialists

• Low reproductive capacity

• Poor competitors

• Large mammals

• Valuable products

• Altruistic species

• Position in the food chain

Umbrella species

large species that require a large habitat. if you protect their habitat, you also protect habitats for other species (e.g. the giant panda)

Flagship species

species selected to act as an ambassador or symbol for a campaign/environmental cause (e.g. panda for WWF)

Keystone species

species that interact in the food web and if lost, leads to the demise of other species. they protect the entire community (e.g. sea otters help the health of kelp forests but are vulnerable to predators, therefore risking kelp forests)

Speciation

occurs when a group within a species separates from other members of its species and develops its own unique characteristics

Natural selection

a natural process resulting in the evolution of organisms best adapted to their environment. Organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success.

Geographical isolation

essential in the formation of a new species. Populations of the same species separate, cannot interbreed and start to diverge if the environments they inhabit change

Reproductive isolation

evolutionary changes to the appearance or behaviour of populations may result in males and females of those populations no longer being attracted to each other and therefore not breeding. the exchange of genes may slow and eventually stop, different species may arise

Constructive margins (plate activity)

the plates move apart from one another. When this happens the magma from the mantle rises up to make new land in the form of a shield volcano.

Destructive margins (plate activity)

The plates move towards one another and this movement can cause earthquakes. As the plates collide, the oceanic plate is forced beneath the continental plate.

Collision margins (plate activity)

when two continental plates move towards each other and collide. The land between the plates is forced upwards to form fold mountains

Conservative margins (plate activity)

the plates are moving past each other or move side by side at different speeds. As they move, friction occurs become stuck. They are trying to move so pressures and stresses build up in the crust. When the pressure is released suddenly, waves of energy move through the crust, causing an earthquake.

Soil ecology

Horizons

layers of soil

Horizon O

organic - ecosystem litter, hummus, organisms

Horizon A

topsoil - decomposing organic layers

Horizon E

subsurface - depleted organic

Horizon B

subsoil - clay

Horizon C

parent material - loose rock

Horizon R

bedrock

Earth’s water budget

all water on earth (70% of earth’s surface)
97% contained in oceans as salt water
3% freshwater

Hydrological cycle

the process where water is constantly recycled between the sea, air and land

Water borne

infection usually occurs from drinking contaminated water

Water washed

indirect infection, through skin, eyes or ears from exposure to contaminated water

Water based

pathogen spends part of life cycle in water. Route of entry into human water

Water related insect vector

spread by insects that breed in or near water

Ground water contamination

run-off/earth causes contaminated of groundwater

Water stress

when demand exceeds the available supply over a certain time period or when the quality of water restricts its use

Water scarcity

insufficient availability of quality water to meet the demands of a region’s population and ecosystems

Water as a resource

• Filtration of un-clean water

• Economic status - infrastructure to support

• Population - is there enough to go around?

• Climate - dry vs humid

• Location - proximity & neighbouring

• There but not usable

• Agriculture grows

Water withdrawl

freshwater taken from ground or surface water sources either permanently or temporarily, and conveyed to a place of use

Water consumption

water use that is not returned to the original water source after being withdrawn

Water waste

water generated after the use of water in a variety of processes

Large scale scarcity (not enough)

• building dams

• rainwater harvesting

• artificially recharged aquifers

Small scale scarcity

• grey water recycling/nighttime watering

• rainwater harvesting

• drip irrigation

• drought resistant crops

Degradation (not usable)

• contamination groundwater (metals)

• salinisation of top soil

• pesticides/fertilisers

• industrial pollutants

Soil systems

a dynamic ecosystem that has inputs outputs, storages and flows

Soil system storages

• organic matter

• nutrients

• minerals

• air

• water

Soil

a mixture of eroded rock, mineral nutrients, decaying organic matter, water, air and billions of living organisms. it is continually changing and developing through physical, chemical and biological processes such as weathering, erosion and translocation

Why soil is important

• grow crops/agriculture

• habitat for organisms

• trees (provide nutrients/root support)

• filters water

Soil pyramid

Factors affecting soil characteristics

• Climate: precipitation/evaporation balance determines the dominant direction of water movement. 

• Organisms: Soil organisms break down the dead organic matter and mix it into the upper layers of the soil.

• Relief: The elevation of the land, the aspect of the slope (the direction it faces) and the angle of the slope

• Parent material: The original material that the soil develops from. It will either be the bedrock (solid rock) or a drift deposit (lake or glacial) that has been laid down on top of the bedrock.

• Time: Therefore the amount of time the soil has had to develop, will affect its characteristics natural capital’s ability to renew

Micro-organisms

bacteria, algae and fungi.

Macro-organisms

earthworms, insects, mites, millipedes and mammals, such as moles.

Soil ecosystem food web

Inputs of soil

• minerals

• organic matter

• gases

• water

Stores of soil

• Organic matter

• Organisms

• Minerals

• Air

• Water

• Nutrients

Outputs of soil

• minerals

• organic matter

• water

• gases

Sand

feel gritty, as the particles are quite big. The large particles create large pores spaces between them. This means that they are:
- Well drained so rarely get water logged.
- Subject to drought in times of low rainfall.
- Warm up quickly in summer due to high air content.

Clay

the smallest and give soil a sticky feel. Small particles give small pore spaces and are:
- Poorly drained and prone to water logging.
- Take a long time to dry out after rainfall.
- Warm up slowly in summer due to high water content.

Silt

too small for the human eye to see and soils high in silt have a smooth feel. The smaller particles give smaller pore spaces