Download Chapter 8 * Section 3

Chapter 8 – Section 3
The Characteristics of
Seed Plants
What are Seed Plants?
• Seed plants outnumber seedless
plants 10 to 1
• Have vascular tissue
• Use pollen and seeds to reproduce
Vascular Tissue
• Meets the Challenges – stand up
straight, supply all cells with food
and water.
• Phloem – food moves through this
tissue
• Xylem – water and minerals travel
through this tissue
Pollen and Seeds
• Do not have to live in water as
don’t have sperm that has to swim
• Pollen-tiny structures that contain
the cells that later become the
sperm
• Seeds are made when the sperm
fertilizes the egg.
– Young plant inside a protective
covering, Right conditions sprout
breaks out of seed.
Seed Structure – Figure
10 p. 264
3 parts
Embryo – plant that develops from
zygote
Seed food – some stored in
cotyledons (seed leaves in embryo)
or outside the embryo
Seed coat – outer covering (protects
from drying out)
Seed Dispersal- scattering
of seeds
• Other organisms waste
• Barbs that hook on other animals
• Wind
• Eject from plant with force
Seed Germination-
when
embryo begins to grow again and
pushes out of seed
• Begins when seed absorbs water
and begin to grow
• Roots grow first downward, stem
and leaves upward
• Seedling- when you see the leaves
• Distance from parent needed
Roots
• 3 Main functions
• Anchor a plant to ground
• Absorb water and minerals from
the soil
• Sometimes store food
Types of Roots- Figure 13
p 267
1. Fibrous Root Systemseveral root systems
that form a dense
tangled mass- grass
2. Taproot Root System –
One long thick root
smaller branching off.
dandelion
Structure of Root-figure
13 p. 267
• Tip round, covered by root cap
(protects from injury from rocks as it
grows)
• Root hairs absorb the water and
minerals, help anchor plant
• Vascular tissue –water moves to xylem
and upward
• Phloem – transports food from leaves to
roots
Stems –
• carries substances between roots
and leaves
• supports
• holds up leaves to get sun
Stem structure- figure p.
268
• Herbaceous – no wood
• Woody
• hard, rigid
• several layers,
• outer layer bark
• Cambium – cells that divide to procduce
phloem and xylem (wood part)
• All have phloem and xylem
Annual Rings
• Made up of xylem
• Summer grow slow and make
small rings
• Spring grow fast and make dark
large rings
Leaves
• Capture suns energy and carry out
the food making process of
photosynthesis
• Come in many different shapes
Structure of Leaf- figure
16 p. 270
• Surface layers
– Protect cells
– Veins that contain xylem and phloem
– Have stomata (pores that open and
close to control gases going in and
out)
• CO2 in and H2O and Oxygen out.
Leaf and Photosynthesis
• Upper surface has most cells with
chloroplasts (chlorophyll in the
chloroplasts trap sun’s energy)
• CO2 enters through stomata
• H2O through the xylem in stem
• Sugar and Oxygen produced from CO2
and H20
• Oxygen out through stomata
• Sugar through plant in phloem
Controlling Water Loss
• Transpiration – water evaporates
from plant’s leaves
– Close stomata when leaves start to
dry out.