AQA Environmental Science A level year 1

Conditions for life - Mass

• Prevents gases escaping into space, and creates enough atmospheric pressure that prevents boiling.

Conditions for life - Distance from the sun

• Suitable distance to produce temperatures appropriate for life (“Goldilocks Zone”) 

Conditions for life - speed of rotation

• The 24 hour period of rotation reduces temperature extremes

Conditions for life - Axis of rotation

• Produces seasonal variation 

Conditions for life - Magnetic field

• The molten layers beneath the crust produce the Earth’s magnetic field. This deflects ‘solar winds’, preventing biologically damaging radiation reaching the Earth’s surface. 

Liquid water

Water is essential to all living organisms, both in terms of their physiology and their environment

Physiology

Solvent, internal transport, temperature control

Environment

anomalous expansion on freezing, absorption of UV rays, aquatic habitats

Atmospheric gases - Carbon dioxide

Used in photosynthesis and the synthesis of carbohydrates, proteins and lipids 0.042%

Atmospheric gases - nitrogen

Protein synthesis 78%

Solar energy

Energy for photosynthesis, most areas on earth between 0-35 - liquid water, drives hydrological cycle

Atmospheric oxygen

Archaea evolved photosynthesis 2.7 billion years ago, 2.4bya in atmosphere - formed ozone, absorb harmful UV

Carbon sequestration

photosynthetic organisms absorb atmospheric c02 some ends up in geological sediments

transpiration

returns water vapour to the atmosphere to increase precipitation - increasing plant growth

Importance of Conserving Biodiversity 

• Human survival is dependant on numerous other species on the planet, in terms of ecological services and resources

Biological resources- food

75% from 12 plant and 5 animal species

Biomimetics

knowledge of adaptations of other species to improve the designs of manufactured items - transport, infection control, architecture, adhesion, materials, medicines

Genetic resources

wild plants have genetic characteristics theat can be used to improve cultivated crops. CRW - crop wild relatives

Gene pool problems

domesticated species have small gene pools - vulnerable to environmental changes and disease

Ecosystem services

• The benefits provided by ecosystems that contribute to making human life both possible and worth living

Threats to biodiversity - direct exploitation

food, fashion, entertainment, furniture and ornaments, traditional medicines

threats to biodiversity - indirect threats

eradication of predators and competition, changes to abiotic factors, changes to biotic factors, introduced species, habitat destruction

Changes in abiotic factors

human activity may alter not destroy a habitat - organism may not be adapted to new conditions, outside range of tolerance

Abiotic factors - temperature

climate change will alter the distribution, hot effluent water - increase growth rates of aquatic vegetation

Abiotic factors - ph

acidic conditions can be caused by mine drainage water, pollutant gases from burning fossil fuels and smelting metals

Abiotic factors - water turbidity

ploughing mining and dredging increase water turbidity - reduces efficiency of photosynthesis and filter feeding

Changes in biotic factors - introduced species

Indigenous species are adapted to the abiotic and biotic conditions of their surroundings - introduced may have adaptation that give them a greater chance of survival

International union for conservation of nature

ICUN categories species according to their vulnerability to extinction

Assessing species

112,000 of 1.6 million known species have been categorised

Threat to a species habitat

the more at threat the habitat the more at threat the species

EDGE

Evolutionary Distinct and Globally Endangered - few close relatives

Endemic species

only found in one geographical area - mainly oceanic islands

Keystone species

Play an important role in maintaining the ecological structure of a community

Flagship species

High public profile - conserving these helps others

Wildlife and countryside Act

1981 - UK law protects UK wildlife. Designated areas (SSSI)

Trade controls

Preventing species from being moved out of a country can prevent them form being caught or killed 

CITIES

Convention on International Trade of Endangered Species - International agreement to prevent trade of wildlife

Appendix 1 - 1000 endangered species cannot be traded

Appendix 2 - 28,000 threatened plant and 3100 threatened animal, only traded with permit

Appendix 3 - 390 vulnerable species cannot be trade in certain countries

IWC

International Whaling Commission regulates and manage whaling

Whales

1900 - industrial whaling

1905- 1925 - peak years

1930 - falling demand

1960 - start of concern

1990 - 5000 whales

present - 10,000 whales

CFP

Common Fisheries Policy - regulates fishing in EU territory

ITTO

International Tropical Timber Organisation - sustainable management of tropical forests

what stops species from breeding in captivity

conditions, gene pool size, habitat, hybridisation

conditions for breeding

breeding is often triggered by environmental stimuli

population interactions

breeding pairs might need to be isolated from non-breeding pairs

breeding habitat

breeding can only take place in a suitable habitat

gene pool size

captive populations have small gene pools - can build up harmful genes

cryopreservation

freezing of gametes or embryos

produced without parents meeting

can last for years

artificial preservation

male gametes into a female

avoids transport, injury and non-acceptance

embryo transfer

transferring embryos to a surrogate mother - closely related species

micro-propagation

taking smiles of cells which are then cultivated into an individual

cloning

transferring nucleus of a stem cell into the egg cell of a closely related species

successful reintroduction

large enough area

reliable food supply

low predation risk

suitable breeding sites

water

hard release

without pre-release - when behaviour is controlled be instinct

soft release

post-release support - gradual release or provisional food

voluntary agri- environmental schemes

69% of uk used for agriculture

since 1950s increase in intensive farming - damaged habitats

unintentional habitat creation

creating reservoirs, verges, ornamental gardens

intentional habitat creation

managing habitats that are currently unsuitable

Antarctica - ecological features

ice+snow 4.8km thick

average -49 degrees c

worlds largest desert

little terrestrial life

high marine biodiversity

Antarctica conservation

CAMLS Conservation of Antarctic Marine Living Resources - prevents overexploitation of marine species

tourism - 1 cruise ship with 100 people

no waste can be left

Taxonomy

grouping organisms according to their similarities

species

a group of organisms that naturally breed and produce fertile offspring

Evolution

process that changes the gene pool of a species

Habitat

The area or location where a species or community lives

Niche

The role a species plays in its habitat

Population

All the individuals of a single species that live in a particular area

Community

Includes all the members of all the species that live in an area

Ecosystem

Abiotic and biotic features of an area and relationships with the physical environment

Biome

A large geographic region with specific climate conditions