Chapter 5 - Life Processes In The biosphere Flashcards Preview

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Flashcards in Chapter 5 - Life Processes In The biosphere Deck (33):

Define: Habitat

The place where an organism, species or population lives.


Define: Population

All the individuals of a species living in a particular area.


Define: Exoskeleton

A skeleton on the outside of an organism such as found in Insects and crustaceans.


Define: Turbulence

The roughness of the environment caused by chaotic air or water flow.


Define: Heterotroph

An organism that gains its organic compounds for energy and growth from other organisms.


Define: Cellulase

An enzyme that digests cellulose that is produced by some bacteria, fungi and protozoans


Define: Cellulose

The carbohydrate made of linked glucose molecules, which is a major component of plant cell walls and wood.


Define: Symbiosis

A relationship between organisms of different species that live together. One benefits while the other species may benefit, be unaffected or suffer.


Define: Mycorrhizal Fungi

Symbiotic fungi associated with plant roots that gain carbohydrates from the plants and aid the uptake of nutrients such as phosphates from the soil by the plants.


Define: Pollination

The transfer of the male plant gamers onto the female part of a flower, resulting in fertilisation and seed production.


Define: Community

A community of species refers to the population of all the species living in a particular area.


Define: Taxonomy

The study of organisms to assess how they may be grouped or classified.


Define: Taxon

A group of organisms based on their biological similarities.


Define: Genus

A group of closely related species.


Define: Ecosystem

The community of organisms living in an area, their inter-relationships and interactions with their abiotic environment.


Define: Biome

A large geographical region with particular climatic features, in which a characteristic, unique community of species lives.


Define: Ecological Succession

The sequences if changes in community composition that changes as an area is colonised and develops until a climax community is eventually produced.


Define: Lithosere

The sequence of changes in community composition as bare rock is colonised and becomes a terrestrial climax community.


Define: Autotrophs

An organism that can capture light or chemical energy from the environment to make high-energy substances such as carbohydrates. They include photoautotrophs and chemoautotrophs.


Define: Secondary Succession

Changes that occur in an area that has already reached the climax state.


Define: Edaphic

A factor related to soil, particularly as it affects living organisms.


Define: Density Independent Factors

A factor that is not influenced by the population density of the species that may be affected, e.g. Drought and volcanic eruption.


Define: Density Dependent Factors

A factor whose effect is affected by the density of the population, e.g. Disease and food supply.


Define: Carrying Capacity

The greatest population that can be supported sustainably in an area.


Define: Sigmoidal Population Growth

The growth pattern of a population where abundant resources allow rapid growth followed by population stabilisation as the carrying capacity is reached.


What are the abiotic (physical) factors of an environment?

- Temperature (low causes cells to freeze, high causes denatured proteins)
- Light (plants have evolved pigments to absorb light)
- pH (high/low cause enzyme damage)
- Water (all organisms require water)
- Mineral Nutrients (animals from food, plants from surroundings)
- Turbulence/Physical Damage (adaptation to strong winds)


What are the biotic (living) factors of an environment?

- Feeding (adaptation for catching, eating and digesting food)
- Avoiding Predators (defence mechanisms e.g. toxins)
- Symbiotic Nutrition (assists others with nutrition e.g. algae and coral polyps)
- Pollination (wind pollination used for plants in dense groups)
- Seed Dispersal (seeds that attract animals)
- Disease (naturally control populations)
- Nutrient Supply (detritivores break-up dead organic matter)


What are the stages of ecological succession for a Hydrosere?

1) Begins in water.
2) Single celled algae colonise freshwater area.
3) Rooted plants (reeds, lilies) colonise lake edges.
4) More animals that arrive survive on colonised plants.
5) Dead plants gradually fill the lake.
6) Open water and aquatic species disappear as lake fills up.
7) Trees (willow, alder) start to colonise as soil develops.
8) Transpiration of trees remove water, oak colonise.
9) Canopy provide shade, prevents small plants growing.
10) Animal species colonise as the conditions become suitable.


What are the different types of Plagioclimax in the UK and how are they managed?

- Lowland Heathland, grazing or burning.
- Hay Meadow, mowing.
- Wet Meadow, grazing.
- Upland Moorland, grazing or burning.
- Arable Field, ploughing.
- Garden Lawn, mowing.
- Coppiced Woodland, felling (8-20 years).
- Reed Beds, mowing or cutting.


What is the Simpson's Diversity Index Formula?

D = N(N-1) \ SumOf(n(n-1))

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

The higher the calculated value, the higher the biodiversity.


Why do many species remain undiscovered?

- Lack of research (ecosystems inaccessible e.g. deep sea floor)
- Identical observations (species have similar appearance, structures and behaviour)
- Males and females look different and live solitary lives (can only tell if they mate)
- Plants identified when flowers produced


How do you calculate a population size?

+ births + immigrants
Starting population
- deaths - emigrants


What are the stages of ecological succession for a Lithosere?

1) Bare rock, harsh early abiotic conditions.
2) Pioneer species (lichen) colonise.
3) Weathered rock fragment and dead organic matter build up.
4) Moss colonise, thin layer of soil builds up.
5) Grasses colonise, abiotic factors less extreme.
6) Soil makes plant nutrients available, seedlings survive under shadow of larger plants.
7) Flowering plants colonise, insects pollinate them.
8) Edaphic factors suitable, trees colonise.