Download BIODIVERSITY OF PLANTS

BIODIVERSITY OF PLANTS
BIODIVERSITY
 A measure of the number and abundance of different species living in
a particular ecosystem
Plants provide food and shelter for other organisms. Therefore if an
ecosystem has a lot of different plant species, it will be able to support
many different animal species.
HIGH PLANT DIVERSITY = HIGH ANIMAL DIVERSITY
TROPICAL RAINFORESTS have the highest biodiversity, both plant and
animal on the planet.
MONOCULTURE
 A habitat dominated by a single plant species
 Examples – food crops (corn, carrots), lawn, apple orchard
LOW PLANT DIVERSITY = LOW ANIMAL DIVERSITY
Just as animals compete for resources (food, shelter, space), plants also
compete for resources. Plant species that are introduced into an area may
out-compete the native species and crowd them out. These are called
INVASIVE SPECIES.
PICTURES OF INVASIVE SPECIES
RAGWEED
CANADIAN THISTLE
OVERVIEW OF PLANT STRUCTURE
Plants are:
 KINGDOM - Plantae
 Multicellular
 Usually autotrophic (make their own energy by photosynthesis)
 Sexual and Asexual reproducers
 Mostly terrestrial (land) and some aquatic (water)
Plants can be placed in 2 categories:
1. SEED PLANTS
2. NON SEED PLANTS
Seed Plant / Non Seed Plant Concept Map
CHARACTERISTICS OF MONOCOTS AND DICOTS
Root System – Fibrous
Root System - Taproot
PLANT TISSUES
There are 4 types of plant tissue:
1. Meristematic Tissue
2. Dermal Tissue
3. Ground Tissue
4. Vascular Tissue
MERISTEMATIC TISSUE
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Cells divided by mitosis;
These cells differentiate into other plant cell types;
1) Apical Meristems
 Found at the tips of roots and shoots
 Responsible for primary growth (lengthening shoots and roots)
2) Lateral Meristems (Cambium)
 Cylindrical regions which increase the diameter of roots and shoots
(secondary growth)
3) Vascular Cambium
 Produces the cells for new xylem (water) and phloem (food)
DERMAL TISSUE
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Outermost cell layers
Function:
o protection from cuts;
o microorganism invasion;
o water loss;
Examples
o Leaves and stems may produce wax (prevent water loss) or fine hairs or
painful irritants (to discourage herbivores)
o Epidermal root tissues develop root hairs to increase water and nutrient
absorption
o Woody plants produce bark for further protection (bark consists of dead
cells)
GROUND TISSUE
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All internal cells except vascular tissues
Function
o Storage
o Support
o Photosynthesis
Examples
o Fleshy portion of apples, pears, potatoes
VASCULAR TISSUE
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For transport of substances in the plants
Xylem
o Transports water and dissolved minerals from roots to the rest of the
plant
o These cells die at maturity and become hollow
o Appearance – thick walls, may be long and thin or shorter with open ends
o When arranged end to end they make continuous tubes for transport
o Wood is 100% xylem tissue  good support for trees
Phloem
o Transports sugar and other nutrients from the leaves (site of
photosynthesis) to the rest of the plant
o Living cells
o Sieve tube element
 Long thin cells with pores at the ends of their cell walls
 No nuclei, mitochondria or vacuoles
 Arranged end to end to form tubes
o Companion cells
 Found beside sieve-tube elements
 Have all the cell organelles that the sieve-tube is lacking
 Control the functions of the sieve tube
DIAGRAMS OF THE VASCULAR TISSUE
ROOTS
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Usually below the ground
Serves 5 functions
o Anchor the plant to the ground
o Absorbs water and minerals
o Store extra sugar during photosynthesis
o Transport water, sugar, minerals and hormones to the remainder of the
plant
o Produces some hormones
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Edible roots include:
o Carrots, radishes, sweet potatoes
2 forms:
1. Tap root
o Large tapering main root
o Example - carrot
2. Fibrous root
o Many smaller roots of equal size that grow out of the bottom of the
plant
o Example – grass
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ROOT GROWTH AND DIFFERENTIATION
Root Cap
o Protective layer of cells at the tip of the root
Apical Meristem
Zone of Elongation
o Newly divided cells from the apical meristem increase
in length
Zone of Maturation
o Root cells differentiate and mature; region with root
hairs
STEMS
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Provide support for the above ground portion of the plant;
Connect roots with the remainder of the plant;
Store water and food;
Transportation system – xylem and phloem are located in the stems
Examples – potatoes
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2 types
1. Woody
o Stems are hard and not easy to bend; strong
o Composed of dead xylem tissue
2. Non-woody
o Soft and bend easily; weak
o Height limits
Vascular Cambium and
Phloem Cells
New Xylem matures into
wood; Annual Ring is the
amount of xylem produced in 1
year
LEAVES

Green leaves (chlorophyll) are the site of photosynthesis
Veins – an extension of the vascular tissue
from the stem
Node – the attachment site of the leaf to the
stem
Internode – the space between
nodes on the stem
successive
SIMPLE AND COMPOUND LEAVES
Simple Leaf – continuous undivided
blade
Compound Leaf – leaf that is divided
into 2 or more leaflet
LEAF STRUCTURE
Epidermal Cells
 1 cell layer of cells covering the upper and lower surfaces of the leaf blade
Palisade Mesophyll Layer
 Cells at right angle to the leaf surface; rich in chloroplasts; site of
photosynthesis
Spongy Mesophyll Layer
 Loosely packed cells with large air spaces; air spaces allow for efficient gas
exchange; site of photosynthesis; leaf veins run through this layer
Stoma
 A small opening in the surface of the leaf which permits the exchange of gases
Transpiration – process of water loss through evaporation out of the leaf
when the stoma are open
Guard Cells
 Control the opening and closing of the stoma; a pair of crescent shaped cells
that surround the pore opening
SEEDS AND FRUIT
Most of the species we eat are angiosperms.
Most commonly the seeds and fruit are used to feed the 6 billion (+) people on the
planet.
SEEDS
The worlds’ 3 most important crops are:
1. Wheat
2. Corn
3. Rice
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Other important crops are soybeans or other beans.
The edible portion of these crops are the seeds
The seeds of these plants are high in protein, carbohydrates and fibre.
FRUIT
 Structure that develops in the ovary of a pollinated angiosperm
 Fruits help the plant spread its seeds
o Maple keys, dandelion fluff are examples of fruits with a form that helps
them spread
o Consumed in animals and pass through the digestive tract unharmed and
are deposited in another location
 Many vegetables are actually fruits – cucumbers, pumpkin, tomatoes, zucchini,
squash
 Other common fruits include bananas, mangoes, apples
POLLINATION
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Process by which pollen is moved from the anther (portion of male reproductive
structure – STAMEN) to the female egg cells and fertilizes these cells.
Some plants can fertilize themselves and others need pollen from a different
plant.
Some plants even have separate male plants and female plants.
The pollen is able to travel between plants in many different ways, wind, animals,
birds, and insects (BEES).
Once the eggs are fertilized they become seeds.
The petals fall and in some species the ovary develops into the fruit.