LIFE SCIENCES GRADE 11

2. Grassland(28.9%)
Nama-Karoo(20.6%)
AlbanyThicket(2.8%)
SucculentKaroo(6.9%)
Savannah (33.2%)
Desert (0.6%)
Forests(0.4%)
Fynbos (6.6%)

3. Taxa (groups of
species)
Number of known Species South African Species
as % of earth’s known
species
South Africa World
Mammals 295 5.8%
Birds 880 8.0%
Amphibians 110 2.1%
Reptiles 286 4.6%
Freshwater fish 220 1.3%
Marine fish 2150 16.0%
Insects 80 000 5.5%
Vascular plants (e.g.
flowering plants,
conifers, cycads and
ferns
23 420 7.5%

4.  ENDEMIC: when a species is only found in
ONE specific area or habitat in the world
 SA = 5th -richest country in Africa
 SA = 24th-richest in the world
 3 Hotspots:
1. SUCCULENT KAROO
2. FYNBOS
3. MAPUTALAND-PONDOLAND-ALBANY

5. • Species and ecosystem diversity ensures the
health of our planet.
• Loss of biodiversity leads to unstable
ecosystems
• Also the loss of clean water, fresh air , food
and medicines.
• HUMAN ACTIVITIES contribute to loss of
species 100 to 1000 times faster than before
• Worldwide = we’re losing 70 species a day.

6.  HABITAT DESTRUCTION
 Cutting down indigenous forests
 Filling in wetlands
 Damming up rivers
 Clearing land for new settlements
 When species lose habitats …..
 They are deprived of food and shelter
 Isolated from others – leads to in breeding
(loss of genetic diversity)

7.  HUMAN POPULATION GROWTH
 Increased demand on energy, food,
minerals
 Using more land, water, trees, fossil
fuels. Minerals, plants and animals
 Increased usage – devastating effects
on biodiversity
 Climate change (global warming)

8.  AGRICULTURAL ACTIVITY
 Indigenous, natural vegetation is cleared
for cultivation and afforestation
 Wetlands are filled to create more land
for farming
 Overgrazing destroys natural vegetation
 Results in soil erosion

9. • INDUSTRY AND MINING
• Industries pollute water, air and soil
• Destroy natural habitats
• Timber industry – loss of habitat for
wildlife
• Trade in wildlife- rhino horn, buchu
• Invasive species (black wattle)

10. • Food and medicine for everyone
• Aesthetic value
• Tourism potential

11. EARLY
VASCULAR
PLANTS
ORIGIN OF
PLANTS
Bryophytes (e.g. Mosses)
FIRST SEED
PLANTS
RADIATION OF
FLOWERING
PLANTS
Pteridophytes (e.g. Ferns, horsetails)
Gymnosperms (e.g. Conifers, Cycads)
Angiosperms

12. PERIOD
NUMBER OF
MILLIONS OF
YEARS AGO
(MYA) EVOLUTIONARY DEVELOPMENT
SILURIAN
435-410
MYA
Land plants evolve from aquatic algae. A cuticle
reduces moisture loss. Sex organs have protective
coat to protect the gametes and embryos
EARLY
DEVONIAN 410 MYA
Land plants develop vascular tissue to conduct
water and food, and give structural support
LATE
DEVONIAN 360 MYA
Some plants develop seeds, which protect the
embryo from drying out
EARLY
CRETACEOUS 135 MYA
Flowering plants appear. Flowers attract
pollinators. Ovaries (fruit) protect the developing
seeds.

13. Plant diversity
general characteristics –present / absent
• Vascular Tissue
• True roots; leaves
• Seeds / spores
• Fruit
• Dependency on water for
reproduction

14. *
Bryophyta (BRYOPHYTES)
* Pterophyta (PTERIDOPHYTES)
* SPERMATOPHYTA (SPERMATOPHYTES- 2 Groups)
1. GYMNOSPERMS
2. ANGIOSPERMS

15.  Habitat
- shady places
- moist
* Structure
- small plants
- 1 to 5 cm high
- no true roots, stems leaves
or vascular tissue (thallus)

16. • Not well adapted for life on
land
• Cuticle either absent/delicate
• Entire surface of plant can
absorb or lose water
• Thallus (primitive roots, stems
and leaves)
• Conducting and strengthening
tissue poorly developed

17. Bryophytes consists of three groups: the
mosses, liverworts and hornworts

18. Veenmos/ Peat moss
(Sphagnum)

19. Life cycle of moss plant

21. Ecological Importance of moss
• Pioneer plant – first to grow in new area
• Plays an important role in Plant succession
• E.g. mosses trap dust and organic material- organic
material rots – produces acids – acids break down
rock to form soil particles – seed of large tree falls on
mossy carpet - germinates
• Bind soil, prevent erosion
• Soil richer in organic matter
• Economic value – source of peat (marshland with
carbonized plant material)

22. • Habitat :
- Moist , shady
* Structure:
- Sporophyte – roots,
stem (rhizome),
compound leaves

23. • 2nd step in evolution
• Have conducting tissue (xylem and
phloem) – (strengthening and vascular)
• True roots – anchor in soil + absorb
water and mineral salts
• Leaves and stems are differentiated
(strength and support)
• Parts above ground = cuticle (to
reduce loss of water)
• Leaves have stomata for gaseous
exchange

25. Life cycle of fern
risoiede

27.  Ecological– role in plant succession,
replace mosses
 aesthetic – gardens, floral arrangements
 Medicinal – as tea, prevent cough
outbursts
sap of leaf as aenema (injection of liquid
in rectum
abscesses
• Economical - tropical tree fern as
building material

28. • 400 MYA
• Most land plants grew in swamps
(WHY?)
• Depended on moist environment for
reproduction
• 3rd stage in evolution = breakthrough to
survive in drier areas WHY?
DEVELOPMENT OF SEEDS

29. Gymnosperms (250-140 Mya)
- Gametes in cones
- True roots, stems and leaves
- Better developed conducting and
strengthening tissue
- Female cones produce ovules
- Male cones – produce pollen
(independent of water – wind)
- Seeds are naked - not
protected inside a fruit
- 700 spesies
Angiosperms(120 Mya)
- Gametes carried in flowers
- True roots, stems and leaves
- Better developed conducting
and strengthening tissue
- Produce ovules within an ovary
- Mono-/ dicotolydenous
• 235 000 species

30. • Habitat
different types – cold , windy , dry,
sandy
• sporophyte – large tree, well-
developed
• taproot system( to obtain water,
anchor)
• Leaves - waxy layer (prevent water

35.  Evergreen – for Photosynthesis
 Wood pulp + paper
 Timber wood for building industry
 Wood for furniture
 Plantations – 53,3% surface
 Resin – for varnish
 Turpentine – from pine wood

36. • Building industry e.g. floor boards,
roof beams
• Famous antiques
• Ripe fruits eaten by bats, bush pigs,
birds
• Birds roost in dense crown

38. Angiosperms ( flowering plants)
LARGEST GROUP OF PLANTS (235 000 SPECIES)
Habitat :
- mesophytes : average water (most)
- hydrophytes : in water
- xerophytes (cacti) : very dry and arid
areas

39. - Sporophytes (flowering plants) have
true roots, stems, leaves, flowers,
fruits, seeds
- Well-developed vascular system
- Taproot system (store food) e.g.
Beetroot
- Stems (underground, store food) e.g
potatoes

42. stamper
meeldraad

44. ginesium ovarium
ovulum
mikrospoor
stuifmeelkorrel
megaspoor
Verdeel 3 keer
deur mitose
Eiersel/ovum
poolkerne

45. • Agricultural – major food source e.g. wheat, rice,
maize, potatoes
• Biofuels
• Economic – building material eg Eucalyptus
• Cultural - thatching reeds (restios)
• Aesthetic – attract tourists
• Medicinal – acetylsalicylic acid from willow bark
to treat leukaemia,
• Quinine from bark of cinchona tree -malaria

47.  BRYOPHYTES
 No vascular tissue
 No true leaves and roots
 Spores
 Depend on water for
fertilisation
• PTERIDOPHYTES
• Vascular tissue
• True leaves and roots
• Spores
• Depend on water for fertilisation
• GYMNOSPERMS
• Vascular tissue
• True leaves and roots
• Seeds
• Fertilisation independent of
water
• ANGIOSPERMS
• Vascular tissue
• True leaves and roots
• Seeds
• Fertilisation independent of
water