Ecosystems overview

Question 1

Define an ecosystem

Answer 1

A particular area in which living (biotic) components interact both with each other and with non-living (abiotic) components

Question 2

Define an ENVIRONMENT

Answer 2

An environment is the sum of the biological, physical and chemical conditions surrounding an organism.

Question 3

E c o l o g y is

Answer 3

the study of relationships and interactions btw :

a) living organisms and living organisms
b) living organisms and their natural environment

Question 4

List 7 ABIOTIC components of an ecosystem?

Answer 4

Physiographic (geography)
Edaphic factors (soil)
Light
Temperature
Water
Atmosphere
Wind

Mneumonic

Question 5

List 2 Biotic components of an ecosystem

Answer 5

Autotrophic (producers i.e. plants)

Heterotrophic (consumers)

• primary consumers eat plants
• secondary consumers eat primary consumers
• tertiary feed on secondary consumers
• decomposers eat dead organic matter and return
  inorganic components back to the environment

Question 6

Abiotic factor of ecosystem:

List 3 physiographic factors of an ecosystem

Answer 6

• aspect (slope direction - affects how much sunlight received)
• slope (affects water runoff and erosion, soil depth)
• height above sea level (temperature, weather extremes e.g. snow/wind)

Question 7

Abiotic factor of ecosystem:

List 5 edaphic (soil) factors of an ecosystem

Answer 7

~ type (clay, loam, sand)
~ soil air 
~ water-holding capacity
~ humus (decaying plants)
~ pH (some plants prefer acid soil or vv)

Question 8

Abiotic factor of ecosystem:

Describe LIGHT factors of an ecosystem

Answer 8

^ day length
^ light strength
^ nocturnal animals

Question 9

Abiotic factor of ecosystem:

How has life adapted to cope with fluctuating Temperature

Answer 9

ectothermic (cold blooded)

# endothermic (warm blooded)
       hibernate or migrate

PLANTS survive winter …..
annuals make seeds
deciduous trees lose leaves
bulbs die back to below ground

Question 10

Abiotic factor of ecosystem:

How has life adapted to cope with fluctuating WATER supply?

Answer 10

• PLANTS
  1. Hydrophyte (in water e.g. water lilies)
  2. Mesophytes (normal water)
  3. Xerophytes (dry e.g. succulents/aloes)
• ANIMALS
  1. get water from food (e.g. Karoo rat)
  2. save water in body (camel excretes concentrated urine)
  3. exoskeleton (insects) or scales (reptiles) to prevent evaporation
  4. live in water (fish, whales)

Question 11

Abiotic factor of ecosystem:

Gases

Answer 11

Animals need oxygen
Plants need CO2
Air is 78% Nitrogen
Air is 21% Oxygen

Question 12

Define the “Water cycle”

Answer 12

The continuous cyclic movement of water between the earth and the atmosphere

Question 13

Explain the following “water cycle” terms:
*evaporation and transpiration

• condensation (cloud formation)
• precipitation (rain, snow, fog, hail, dew, frost)
• run-off
• infiltration

Answer 13

Evaporation