This document provides an overview of key concepts in ecology including the biosphere, biomes, ecosystems, and nutrient cycles. It defines important terminology like community, biome, abiotic and biotic components. It describes the major biomes like tundra, grasslands, forests and aquatic biomes. It explains how ecosystems are structured, including producers, consumers, and decomposers. Energy flows through ecosystems in food chains and webs. Nutrients like carbon, nitrogen, and water cycle through the biosphere and are reused by organisms.

1. UNIT 10: BIOSPHERE,
BIOMES AND
ECOSYSTEMS
Refer to Chapter 52 – Campbell
and Reece, 2010, learning guide
notes and slides

2. ECOLOGY:
The study of the interaction between
organisms and with the environment to
ensure survival and reproduction

3. IMPORTANT TERMINOLOGY
•Biosphere:
Zone of air, land and water at the surface of the Earth
in which living organisms are found.
•Community:
A group of organisms of different species living in a
specific area at a specific time and interacting with
one another.
•Biome:
One of the biosphere’s major communities, charac-
terized in particular by certain climatic conditions
and particular types of plants and animals.

4. IMPORTANT TERMINOLOGY
•Biotic organisms:
Living organisms, including animals, plants, fungi,
bacteria, viruses ect.
•Abiotic components:
Non-living things in the environment e.g. light,
gasses (air), water, soil, temperature.
•Ecosystem:
A biological community together with the abiotic
environment, characterized by the flow of energy and
the cycling of inorganic nutrients.
•Biodiversity:
Total number of species found in an area.

5. BIOSPHERE:
The biosphere is the entire part of the earth
that can maintain life.
It includes the :
Atmosphere,
Lithosphere and
Hydrosphere.

6. ATMOSPHERE:
The lower part above the soil.
Makes up a layer of gases, airborne particles
and water vapour that surrounds the earth.
The most important gasses are:
nitrogen (78%),
oxygen (21%) and
carbon dioxide (0.03%)

7. LITHOSPHERE:
Includes the land masses made up of soil and
rock.
The lithosphere is important for the
following reasons:
It provides the substrate for habitat for plants and
animals.
It is a source of minerals essential for growth and
maintenance.
It provides air and water to roots of plants and soil
animals.
It plays an important role in biogeochemical cycles.

8. LITHOSPHERE:

9. HYDROSPHERE:
oRefers to the part on earth that consist of water
e.g. rivers, dams, oceans, lakes, ponds, streams.
oWater covers ¾ of the earth’s surface.
The hydrosphere is important for the following
reasons:
oIt provides water which is most important consti-
tuent of all living organisms
oIt provides the rainfall that supports terrestrial
ecosystems.
oOcean currents have enormous influence on
climatic conditions in all parts of the world.

10. HYDROSPHERE:

11. BIOMES:
A specific area in the biosphere,
characterized by a specific climate and
occupied by specific animals and plants
It is divided into 2 types of major
biomes:
♥Terrestrial biomes
♥Aquatic biomes

12. :
Terrestrial biomes
•Tundra
•Grasslands (savannas)
•Deserts
•Forests(coniferous-and deciduous-
and tropical rain forests)
•Shrub lands

13. :
Tundra biome
Is the coldest of all the biomes.
Tundra, means treeless plain.
It is noted for its frost-molded landscapes,
extremely low temperatures, little
precipitation, poor nutrients, and short
growing seasons

14. :
Is a tropical grassland with some clumps of trees.
Has wet and dry season.
Average Annual Rainfall- 59 in.
Average Temperatures in the Dry Season- 93º
Average Temperatures in the Wet Season- 61º
PLANTS
Wild grasses, generally tall and several clumps of trees.
These trees can be palm, pine, and acacia.
ANIMALS
Animals, mainly herbivores, are generally large in size.
Animals include elephants, giraffes, zebras, gazelles, and
wildebeeste. Carnivores, such as the lions, leopards, and
hyenas, balance out the ecosystem.
Grasslands (savannas)

15. :
Grasslands (savannas)

16. :A desert is a dry area where less than 50 cm
of rain falls each year.
About one fifth of the Earth's surface is desert.
Deserts can be hot or cold.
Short grasses can be found in nearly all deserts.
Desert plants include sagebrush, creosote
bushes and cacti.
Deserts are home to many reptiles, insects,
birds, and small mammals.
Deserts

17. :
Deserts

18. :Coniferous forest
Deciduous forest
Tropical rain forest
Forests are characterized by the greatest
diversity of species.
Temperature is on average 20-25° C
Forests

19. :
Forests

20. :
Characterized by shrubs, grasses, herbs
and geophytes.
Herbivorous, rodents, birds and insects
are found in this biome.
Wide open spaces provide favorite
nesting and hunting perches for crows,
common ravens, and raptors.
Rodents, like the vole, survive by taking
advantage of the natural cover comprised
of the vegetation.
Shrub lands

21. :
Shrub lands

22. :Wetlands
Marshes
Swamps
Bogs
Lakes
Oceans
Ocean currents
Intertidal zones
Aquatic biomes
Wetland
Marshes
Swamps
Bogs
Intertidal zone
Oceans and Ocean currents

23. BIOMES OF SOUTH
AFRICA:
Biomes of South Africa:
•Succulent Karoo
•Savannas
•Fynbos
•Grasslands
•Forests
•Nama-Karoo
•Marine and Coastal
Ecosystems
•Wetlands

24. :
ABIOTIC AND BIOTIC
FACTORS
The two main components
which influence an organism in
its natural habitat, are the
abiotic (non-living) and biotic
(living) components.

25. ABIOTIC
FACTORS:
Abiotic components include the following:
Temperature,
water,
soil,
light,
physiographic factors.

26. TEMPERATURE:
Cold blooded organisms?
Warm blooded organisms?
Day plants and animals?
Nocturnal animals and plants?

27. Adaptations of plants to temperature
changes
1. Seed germination: most seeds will
germinate only after exposure to a period of
low temperature.
2. Deciduous trees: shed their leaves in
autumn to limit their metabolic processes,
like photosynthesis and growth.
3. Annuals: Survive cold seasons as seeds
4. Geophytes: are perennial plants with their
resting buds below ground level, e.g. bulbs,
rhizomes, corms and tubers.

28. Adaptations of animals to temperature
changes:
1. Exothermic animals (coldblooded animals)
cannot maintain their own body temperature, -
hibernate (winter sleep) during the cold months,
or they can lie on a rock in the sun to warm their
bodies and barrow in the sand to cool down.
2. Endothermic animals (warm blood animals)
maintain a constant body temperature and aren’t
influenced by the fluctuations of the
environmental temperature. But some of these
animals hibernate during the cold winter months
because food is scares.

29. Adaptations of animals to temperature
changes:
1. Body covering: Thick fur, feathers and
layers of body fat help mammals and birds
to keep them warm.
2. Migration of birds: some birds fly to warmer
parts of the world during the cold months, it
is a seasonal movement.
3. Aestivation: During the hot dry summer
months snail aestivate (summer sleep)

30. WATER:
 Main component of living cells and is
essential for all living organisms.
 65% of the human body and 90% of plant
bodies consist of water.

31. Adaptations of plants to meet their water
requirements
XEROPHYTES
HYDROPHYTES
MESOPHYTES

32. LIGHT:
Plants need light for photosynthesis – to
produce food.
Food provide energy for animals.


33. Adaptations of plants to light intensity:
Sun plants: these plants can tolerate a lot of
light intensities.
Shade tolerant plants: grow in shade, big
leaves to absorb as much light possible e.g.
ferns.
Phototropism: The growth movement is the
tropic responses of shoots and roots of plants to
the stimulus of light. Shoots are positive
phototropic and roots are negative phototropic.
Floral initiation: Some flowers open in high light
intensity and some close in high light intensity,
this is due to their type of pollinators.

34. Adaptations of animals to light intensity:
Many animals need light to find food, hiding places,
nesting sites and mating partners, and to escape their
enemies.
Day, night and twilight animals:
Diurnal animals are active during the day,
Nocturnal animals are active during the night.
 Crepuscular animals are active mainly during twilight.
Pigmentation: Pigments (dark skin) absorb the
ultraviolet light of the sun to prevent the deeper laying
tissue from damaging.

35. Adaptations of animals to light intensity:
Migration: Birds and some mammals move to different
places during the autumn months when the daylight
hours decrease.
Reproductive behaviour: The longer days of spring
cause the reproductive organs of many animals to start
growing, this gives rise to their breeding season.

36. Soil / edaphic factor

37. SOIL:
Soil is the habitat of most plants which are of
importance to produce food.
Soil have different pH.
Most plant species prefer a neutral pH of 7.
Acid soils are usually infertile because the
acidity makes the mineral salts very soluble.
Humus forms part of the topsoil, a dark
coloured soil that consist of the remains of dead
organic matter.
Humus is the fertile part of the soil.

38. SOIL:
Three types of soil are found: Loam, clay and
sand.
Loam is the most fertile.
The type of soil can be identified according to:
particle size, stickiness, air content and water-
retaining ability.
Soil contains the water and minerals needed by
plants to grow in.
 Many animals have a habitat in the soil.

39. Physiographic factor
ASPECT:
Position of an
area with relation
to the sun
SLOPE:
ALTITUDE:
height above sea level
•can affect the rate of water run-off.

40. BIOTIC COMPONENTS
OF AN ECOSYSTEM
The biotic component is that part of the total
environment created by living, interacting organisms.
The living components of an ecosystem consist of
producers, consumers and decomposers.

41. Producers (plants)
The sun which is the primary source of energy, gives
energy to the plants to produce food through
photosynthesis.
Plants use the light, carbon dioxide, water and the
green pigment chlorophyll in their leaves to produce
sugars and oxygen.
These plants that produce food through photosynthesis
are called producers.
They are autotrophic organisms because they can
manufacture their own food.
Plants are the most numerous of all the biotic
components.

42. Producers (plants)
Plants that are not found naturally in an area are
called invader plants and could cause other
endemic plants to die out, because the invader
plants use a lot of water.
Many plants have medicinal value.
Sutherlandia frutesence used to treat the
symptoms of flu.
Aloe contain which is used as a laxative
ingredient .

43. Consumers (Animals)
Animals are consumers because they are,
directly/indirectly dependent on the food
produced by the producers (plants), they
consume this food.
Consumers therefore have a heterotrophic
feeding method – they cannot make their own
food and are dependent on the producers for
nutrition.

44. Different types of consumers are found:
Primary consumers:
They feed directly on producers – called herbivores.

45. Different types of consumers are found:
Secondary consumers:
They feed on the primary consumers – include
carnivores (eat meat) and omnivores (eat meat
and plants).

46. Different types of consumers are found:
•Tertiary consumers:
•They feed on primary and secondary consumers.
They are also carnivores. Animals that feed on
dead bodies of animals are called scavengers.

47. Decomposers
Decomposers are micro-organisms that break
down complex organic matter into simple
inorganic matter.
They obtain their energy for the decaying
animals and plants.
They are heterotrophic animals.
We refer to them as saprophytic organisms.
They include fungi and bacteria.

48. BIODEGRADABLE AND NON-
BIODEGRADIBLE
Today we mainly use biodegradable substances
in our everyday life; these are substances that
can be broken down by these decomposers,
which replace the useful elements back into the
soil for plants to grow.
Non-biodegradable substances e.g. plastic, glass
ext. are harmful to the environment because it
cannot be broken down into useful elements.

49. ENERGY FLOW
Energy flow begins when producers absorb
solar energy for the process of photosynthesis.
Energy flows through an ecosystem via
photosynthesis because as organic nutrients
pass from one component of the ecosystem to
another, such as when an herbivore eats a plant
or a carnivore eats an herbivore, only a portion of
the original amount of energy is transferred.
Eventually the energy dissipates into the
environment as heat.

50. ENERGY FLOW
Only about 10% of the food energy taken in by
an herbivore is passed on to carnivores.
A large portion goes to detritus feeders
(decomposers) via defecation, excretion and
death, and a large portion is used for cellular
respiration.

51. ENERGY FLOW

52. TROPHIC LEVELS:
•A trophic level is a level of nourishment with in a
food web.
•The trophic levels are:
•producers (plants),
•primary consumers (herbivores),
•secondary consumers (carnivores +/ omnivores),
•tertiary consumers (carnivores and scavengers) and
•decomposers (fungi and bacteria)

53. FOOD CHAINS
The interaction of the autotrophic and
heterotrophic components in which one organism
consumes another, is called a food chain.
In a food chain there is a continuous flow of energy
from the sun, through the plants to the various
animals.
In a food chain there are always a producer and a
consumer.
All food chains begin with a green plant and may
consist of three to five links.

54. EXAMPLES OF FOOD CHAINS:

55. FOOD WEB:
Consists of various food chains that interact with one
another, therefore, interacting of energy flow within an
ecosystem – it can be described as a diagram which shows
trophic/feeding relationships)

56. FOOD PYRAMID
Number pyramid – Pyramid constructed to show
the relationship between the different numbers of
each trophic level.
Energy pyramid – Pyramid constructed to show
the amount of energy received by each trophic
level.
Biomass pyramid – Pyramid constructed to
show the dry weight of each trophic level in an
ecosystem.

57. FOOD PYRAMIDS

58. INVERTED FOOD PYRAMIDS
Have more herbivores than producers.

59. NUTRIENT CYCLES
The inorganic substances e.g. carbon,
hydrogen, oxygen, nitrogen, phosphorus etc.
within an ecosystem can be used over and over
again.
They are in limited supply.
Therefore they have to be cycled and re-used.
Different important nutrient cycles are:
1.Nitrogen cycle
2.Carbon cycle
3.Oxygen cycle
4.Water cycle

60. WATER CYCLE

61. NITROGEN CYCLE

62. CARBON CYCLE

63. OXYGEN CYCLE