AQA A-level Physical Geography

Define positive feedback

A type of regulation that responds to a change in conditions by initiating responses that will amplify the change.

Define Lithosphere

Store of carbon on land

Define Biosphere

Store of carbon in animals and vegetation

Define Cryosphere

Store in frozen water

Define Open system

a system that can freely exchange matter and energy with its surroundings

Define Isolated system

energy and matter are prohibited from entering and leaving

Define an input

Material or energy moving into the system from outside of the system

Define a provisionary service

Any type of material benefit to people which can be extracted from nature for example water or timber

What is the percentage of vegetation cover on the embryo dune

80%

What are the 5 layers of the TRF (From top to bottom)

- Emergent layer

- Canopy

- Understorey

- Shrub layer

- Forest floor

Define adaptation

The process of becoming better suited to a new environment

What are 2 terms of COP21 (Also known as the Paris Accords)

- Limit average global temperature to increase to 1.5 degrees celsius

- Provide adaptation support for developing countries

Define Mitigation

the action of reducing the severity or seriousness of something

Define Intermitent

Water that flows during wet seasons

Define a Sere

Succession within a certain area

Define an output

Material or energy moving from within the system to outside the system

Define flows

The movement of matter or energy from one store to another

Define Atmosphere

Store in air

Define discharge

the quantity of water in a stream that passes a given point in a period of time

Why is sand closer to the sea more alkaline

Due to seas shells being within the sand as sea shells are made of calcium carbonate which is alkaline

7 characteristics of deciduous woodlands

- Found between 40 and 60 north and south of the equator

- Rainfall: 500-1500mm annually

- Seasonal

- Trees with broad leaves

- Rich in moisture

- Mineral rich soil

- Structure: Canopy; understory; shrub layer and ground layer

Define Arresting factor

A natural or human factor which alters the process of succession

What type of system is an ecosystem

open system

Define closed system

A system in which matter is not allowed to enter or leave, but energy is

Define epheneral

Water flows following a precipitation event

Define perenial

Water that flows all year round

Define Stores

The individual elements or parts of a system

Define supporting services

Services needed to maintain the function of ecosystems

What percentage of plants' biomass does carbon make up

50%

What are the 6 ways to measure biodiversity

- Species richness

- Population number

- Genetic diversity

- Species evenness

- Indicator species

- Living Planet Index

What are 3 impacts of humans on ecosystem services

- Altering land habitat

- Modifying ecosystem structure

- Changing biogeochemical cycle

Define Ecosystem

A biological community of interacting organisms and their physical environment.

Define abiotic

non-living

Define regulating services

An ecosystem service which helps maintain the environment such as via regulating climate, food quality, or water quality.

Define Plagioclimax

The climax community produced when the process of succession is altered by human activities.

Define Cultural service

a non-material benefit that contributes to the development and cultural advancement of people

Define Xerosere

succession in a dry habitat

Define climatic climax

The final stage of uninterrupted vegetation succession (usually woodland).

Define seral stage

Each stage of community change during the process of succession

Define biotic

living

Define Hydrosere

succession in a freshwater habitat

Define Lithosere

Succession on bare rock

Define Psammosere

A succession on sand dunes

What is the equation for discharge

Discharge= velocity (m/s) x cross sectional area (metre squared)

Define Negative feedback

A type of regulation that responds to a change in conditions by initiating responses that will counteract the change.

Define Halosere

succession in a saline environment.

Percentages of gases in the atmosphere

77% Nitrogen

22% Oxygen

1% Other gases

What is the percentage of vegetation cover on the yellow dune

70-80%

Define Confluence

The junction of two rivers joining together

Define Baseflow

sustained runoff of a river for example average streamflow

Define Watershed

An area of land which is drained by a river and its tributaries

What percentage of the Amazon has been lost in the past 50 years to deforestation

17%

What are the 6 types of human activity in the TRF

- Agriculture

- Logging

- Mining

- Road construction

- Energy creation

- Settlement growth

What is the name of the soil found within the Tropical Rainforest

Latosol

What are 5 Characteristics of a Tropical Rainforest

- Low diurnal temperature range

- Annual temperature range as low as 2 C

- High rainfall of around 2000mm

- Year round growing season

- High humidity

Define humus

The Fertile layer of the latosol, found nearest to the top

What percentage of all living organisms does the Tropical Rainforest support

50%

What percentage of the earths surface do Tropical Rainforests cover

5%

Where are Tropical Rainforests mostly located

Along and either side of the equator

Define reducer organisms

Organisms which complete the flow of energy through the chain by returning any remaining nutrients to the soil to support new plant growth.

What are the four phases of heather moorland (From start to finish)

- pioneer phase

- building phase

- mature phase

- degenerate phase

Where are warm water coral reefs predominantly found

between the tropics

6 environmental conditions that create coral reefs

- Temperature- average temperature of 18 C and above with ideal conditions being between 23 C and 25 C

- Salinity- can only tolerate salinity that is close to that of seawater

- Acidity- thrive in high levels of alkalinity

- clear water- corals survive best in clear, unpolluted water as sediment clogs their feeding structures and reduces amount of light

- light- corals feed on algae which need light to photosynthesise, therefore coral reefs are found in relatively shallow water at usually 25m or less in depth

- air- upward growth is limited to tides due to air killing corals

What happens to coral if seawater becomes more acidic

it can stunt growth and even kill them e.g. through increased absorption of carbon dioxide

How does coral grow?

through the use of Zooxanthellae which live within corals tissues and are able to photosynthesise

What are the 6 threats to coral reef ecosystems

- major drainage basin schemes which can wash silt in to the sea clogging their feeding structures

- land clearance and onshore coastal developments can lead to pollutants entering the water

- desalination plants which can increase water salinity and temperatures

- nutrient rich agricultural and sewage discharges can lead to the growth of algal blooms which can smother the coral

- physical damage from fishing and tourism

- climate change

What are 4 Values of the Andros Barrier Reef

- Coastal protection

- Fish breeding grounds

- Tourism

- Healthy coral reef

how much income does tourism on the Andros barrier reef bring to the economy of the Bahamas annually

US $150 million

What are 4 threats to the Andros barrier reef

- climate change

- pollution

- overexploitation

- hurricanes

What are 4 management strategies on the Andros barrier reef

- Andros westside national park (2002)

- North and south marine parks (2002)

- Crab replenishment reserve

- Exuma cays land and sea park

Define Gabions and their purpose

- Steel mesh cages filled with small rocks.

- To absorb wave energy.

Define Groynes and their purpose

- Large linear structures that are built perpendicular to the shoreline.

- They are built to stop the movement of sediment due to longshore drift.

What type of system is a coast?

Open

Where does the prevailing wind of the UK come from?

South-west

3 factors that affect wave energy

- The strength of the wind, which is determined by the pressure gradient

- The duration of the wind, the longer the wind blows, the more powerful the waves will become

- The fetch, the distance of open water which the wind blows. The longer the fetch the more powerful the waves.

How are waves formed?

As air moves across the water, frictional drag disturbs the surface and forms ripples and waves. In the open sea, there is little horizontal movement of water. Instead, there is an orbital motion of the water particles. Close to the coast, horizontal movement of water does occur as waves are driven onshore to break on the beach.

What are the two types of wave?

- destructive

- constructive

What are the 5 Characteristics of a constructive wave

- Distant weather systems generate these waves in the open ocean

- Low, surging waves with a long wavelength

- Strong swash, weak backwash

- Results in beach gain

- Usually associated with a gentle beach profile- although, over time, they will build up the beach and make it steeper

What are the 5 Characteristics of a destructive wave

- Local storms are responsible for these waves

- High, plunging waves- with a short wavelength

- Weak swash, strong backwash

- Results in beach loss

- Usually associated with a steeper beach profile- although, over time, they will flatten the beach

How many high and low tides does the UK coastline experience each day?

Two high and two low tides

Define tidal range

The relative difference in height between high and low tides

Define a rip current

strong localised underwater currents that occur on some beaches which poses considerable danger to swimmers and surfers. They are commonly formed when a series of plunging waves cause a temporary build up of water at the top of the beach. Met with resistance from the breaking waves, water returning down the beach is forces just below the surface following troughs and small undulations in the beach profile.

Where do high energy coastal environments tend to be in the UK? (2 points)

- Stretches of the Atlantic-facing coast, where the waves are powerful for much of the year

- Where the rate of erosion exceeds the rate of deposition

What type of coastal environments do erosional landforms tend to be found at?

High energy environments

Where do low-energy coastal environments tend to be found at? (2 Points)

- stretches of the coast where the waves are less powerful or where the coast is sheltered from large waves

- where the rate of deposition exceeds the rate of erosion

What types of landforms tend to be found in low energy environments?

Depositional landforms

What are the 6 main sediment sources at coasts?

- Rivers

- Cliff erosion

- Longshore drift

- Wind

- Glaciers

- Offshore

Define a sediment cell

A stretch of coastline, usually bordered by 2 prominent headlands, where the movement of sediment is more or less contained

3 Examples of mechanical weathering at the coast

- Freeze thaw

- Onion Skin Weathering

- Wetting and drying

3 Examples of biological weathering at the coast

- Thin plant roots grow and split open small cracks

- Water running through decaying vegetation becomes acidic

- Marine organisms burrow in to rocks for example a piddock

3 Examples of chemical weathering at the coast

- Carbonation

- Oxidation

- Solution

7 Types of mass movement

- Soil creep

- Mudflows

- Landslide

- Rockfall

- Landslip or slump

- Runoff

- Solfiluction

Define soil creep

a persistent, gradual mass movement of surface soil

Define a mudflow

A fluid stream of mud flowing downhill over unconsolidated or weak bedrock, often occurring after heavy rainfall.

Define a landslide

Blocks of rock moving rapidly downhill along a planar surface.

Define rockfall

the sudden collapse or breaking away of individual rock fragments at a cliff face.

Define landslip

Differs from a landslide in that is slide surface is curved rather than flat

Define runoff

When overland flow occurs down a slope or a cliff face, small particles are moved downslope to enter the littoral zone, potentially forming and input into the sediment cell

Define solifluction

similar to soil creep but specific to cold periglacial environments.

What are the 5 Types of erosional processes found at the coast

- Hydraulic action

- Wave quarrying

- Abrasion

- Corrasion

- Solution