Chapter 5 - Life Processes In The biosphere

Question 0

Define: Population

Answer 0

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

Question 1

Define: Habitat

Answer 1

The place where an organism, species or population lives.

Question 2

Define: Exoskeleton

Answer 2

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

Question 3

Define: Turbulence

Answer 3

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

Question 4

Define: Heterotroph

Answer 4

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

Question 5

Define: Cellulase

Answer 5

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

Question 6

Define: Cellulose

Answer 6

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

Question 7

Define: Symbiosis

Answer 7

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

Question 8

Define: Mycorrhizal Fungi

Answer 8

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.

Question 9

Define: Pollination

Answer 9

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

Question 10

Define: Community

Answer 10

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

Question 11

Define: Taxonomy

Answer 11

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

Question 12

Define: Taxon

Answer 12

A group of organisms based on their biological similarities.

Question 13

Define: Genus

Answer 13

A group of closely related species.

Question 14

Define: Ecosystem

Answer 14

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

Question 15

Define: Biome

Answer 15

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

Question 16

Define: Ecological Succession

Answer 16

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

Question 17

Define: Lithosere

Answer 17

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

Question 18

Define: Autotrophs

Answer 18

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.

Question 19

Define: Secondary Succession

Answer 19

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

Question 20

Define: Edaphic

Answer 20

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

Question 21

Define: Density Independent Factors

Answer 21

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

Question 22

Define: Density Dependent Factors

Answer 22

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

Question 23

Define: Carrying Capacity

Answer 23

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

Question 24

Define: Sigmoidal Population Growth

Answer 24

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

Question 25

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

Answer 25

• 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)

Question 26

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

Answer 26

• 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)

Question 27

What are the stages of ecological succession for a Hydrosere?

Answer 27

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.

Question 28

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

Answer 28

• 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.

Question 29

What is the Simpson’s Diversity Index Formula?

Answer 29

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.

Question 30

Why do many species remain undiscovered?

Answer 30

• 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

Question 31

How do you calculate a population size?

Answer 31

+ births + immigrants
Starting population
- deaths - emigrants

Question 32

What are the stages of ecological succession for a Lithosere?

Answer 32

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.