BASIC BIOLOGY NOTES Sem 1 Part 2

BIOLOGY NOTE’S PART 2
Plant Diversity:
 The Evolutionary Origins of Plants
 Plant Life Cycles
 Mosses, Liverworts, and Hornworts
 Seedless vascular plants
 Gymnosperms and Angiosperms
THE EVOLUTIONARY ORIGINS OF PLANTS

 Plants are the evolutionary descendant of green algae
 A single species of green algae gives rise to the entire
terrestrial
plant lineage from moss through flowering plants (angiosperms-
more complex structure: got stems, root, etc)
 Two groups exist: Presence OR Absence of vascular tissues which
facilitate the transport of water and nutrients in plants.
 Non vascular plants are known as Bryophyta.
 Phyla namely mosses, liverworts and hornworts lack vascular tissue
and are referred to as non-vascular plants
 9 out of 12 plant phyla are called vascular plants (among the ferns,
conifers (gymnosperms) and flowering plants (angiosperms)
 Plants are multicellular and mostly photosynthetic
 Can be found in water and on land
 They are primary producers; autotrophs and are fundamental in the
food chain
 Non vascular plants don’t have any special tissue to develop its
growth, they usually live-in areas that have moisture, they are not
tall, not more than 7cm
 AUTOTROPHS – Phototrophs produce their own food by
photosynthesis/ Chemotrophs produce their own food by utilizing
chemical energy
 HETEROTROPHS – plants that are unable to produce their own food
and have to depend on others (parasitic and saprophytic plants;
fungi and mushroom)
 Four major groups of plants include NON VASCULAR PLANTS, SEELES

VASCULAR PLANTS, GYMNOSPERMS and ANGIOSPERMS
 HYDROPHYTES – half the plant is submerged in the water
 HALOPHYSTES – grow in areas of saline water(salty)
 HYGROPHYTES – grown in areas that are shady
 MESOPHYTES – flowering plants (not vascular but have flower)
 XEROPHYTES – grown in areas with lack of water, stem stores water
 EPIPHYTES – grown on other plants to live
BRYOPHYTES
 BRYOPHYTES require water to reproduce sexually, highly adapted
 Gametophytes of mosses consists of small leaflike structures
arranged spirally or alternatelya round a stemlike axis
 They are only one cell think except at the midrib, lack vascular
tissues
 Liverworts are less complec than mosses, gametophytes are
prostrate instead of erect
-must know the main phylums of flowering

plants
PLANT FORM AND FUNCTION
- Meristems elaborate plant body
- Three basic tissues in plants
- Root zones
- External structure of leaves
Meristems
- Its tissues are lumps of small cells with dense cytoplasm and
proportionately large nuclei (act as stem cell in animal cells)
- Cork cambium is important for avoiding transpiration, avoid water
loss from plants
- Vascular cambium protects the grid of plants
- Apical meristem is in the top, thus it grows first
- Primary growth- controlled by root apical meristem
- Sec growth controlled by two later meristems (vascular cambium &
cork cambium)
- Not all plants exhibit sec growth
Organisation of body plan
- Vascular plant got root system and shoot system
- Hairy root help absorption of water
- Root system anchors the plant and penetrates the soil (water & ions
crucial to plant’s nutrition)
- -shoot system consists of stem and their leaves
- Stems is the principal site of photosynthesis
- Axillary bud allow plant to branch
Basic tissue in plants (ground, dermal, vascular)
Ground tissue- Parenchyma
- Consist of thin-walled cells
- More or less spherical
- Most abundant cells of primary tissues
- Cells function in storage, photosynthesis
Ground tissue- Collenchyma
- Have living protoplast and may live for many years
- Longer and wide, have wall that vary in thickness
- Provide support for plant organs, allowing them to bend without
braking
- Form strand of continuous cylinder beneath the epidermis of stems
or lead petioles
Ground tissue- Sclerenchyma
- have tough thick walls
- lack living protoplasts when they are mature
- the sec cell wall has lignin (fibre and sclereid_
- strengthen plant tissue
VASCULAR TISSUES
Xylem
- principle water conduction tissues of plants
- contains combination of vessel
- stomata involved
- even if you cut, still can go through
Phloem
- located toward the outer part of roosts and stems
- got sieve tube
- got companion cells that carry out some of the metabolic functions
that are needed to maintain the associate sieve tube member
dermal tissues
Epidermal Cells
- composed of the epidermis
- protect plants from invasion of any environmental destruction
- trichomes are hairlike outgrowths of the epidermis
- root hairs keep the root in intimate contact with the surrounding soil
particles and greatly increase the root’s surface.
ZONES OF ROOT STRUCTURE
root cap
- to protect the delicate tissues behind it as growth extends the root
through most abrasive soil particles
the zone of cell division
-
the zone of elongation
- Growth increases horizontally
The zone of maturation
- Root hairs gets sloughed off, new ones will grow
EXTERNAL LEAF STRUCTURE
- Leave got blade aka lamina, widest part of the leave
- Some plants got petiolate
- Some got midrib
Phyllotaxy
- Known as arrangement of leaves on a stem
- Num and placement of plants will vary with exhibit a characteristic
leaf arrangement
- Arrangement is classified as either alternate, opposite or whorled
Simple and Compound Leaves
- The lamina is completely undivided
- A palmately compound resembles the palm of a hand
- Pinnately compound, arranged along midrib
- Trifoliate compound
Venation
- Vein is vascular bundle coming to the leaf from stem
- Arrangement of veins is called the venation patten
- Vein carries all the food and water (transportation)
Margin
- Keliling daun
- Outline of a simple leaf or leaflet
- Those with irregular wavy margins are undulates
- Got lobate leaves that may be palmately lobate or pinnately lobate

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BIOLOGY NOTE’S PART 2

 Plant Life Cycles

 Mosses, Liverworts, and Hornworts

 Seedless vascular plants

 Gymnosperms and Angiosperms

THE EVOLUTIONARY ORIGINS OF PLANTS

 Four major groups of plants include NON VASCULAR PLANTS, SEELES

-must know the main phylums of flowering

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