Plants
Characteristics of Plants
• All are multicellular
• Autotrophs (make own
food by
photosynthesis); few
are carnivorous
• Cells are eukaryotic
and have cell walls
Characteristics of Plants
• Life cycle alternates between a sexual phase
(gametophyte) and an asexual phase (sporophyte)
Characteristics of Plants
• Absorb nutrients from
ground
• Exchange gases (CO2
and O2 ) through
stomata in their leaves
• 2 major types:
Nonvascular and vascular
Nonvascular Plants
• Mosses, liverworts, hornworts
• Lack vascular tissue (tubes that transport
food, water, and minerals throughout the
plant)
• Water and nutrients travel from one cell to
another by diffusion and osmosis
• Must be extremely short and live in moist
environments
Nonvascular Plants
Vascular Plants
• Some produce spores
to reproduce (ferns &
horsetails)
• Some produce seeds to
reproduce
Why are seeds better?
They protect the embryo!
Vascular Plants
– Gymnosperms- most
are cone-producing &
have needles.
• Ex.: conifers (pine, fir,
spruce)
• Pollen fertilizes the
ovule, a seed develops
on the scale of a cone,
and then the scales open
enough to allow the
seed to be carried by
wind
Vascular Plants
• Angiosperms –
flower-producing
plants
– Pollen enters the top of
the pistol and travels
down to fertilize the
ovule. The seeds
develop in the ovary
(which will become the
fruit) and are usually
dispersed by animals.
Vascular Plants
• Have vascular tissue that transports
materials and provides support and stability.
(makes up the stem)
• Can grow tall and live in a variety of
habitats.
Leaf Cross-Section
Cuticle is waxy to prevent water loss.
stomata
What comes in and what goes out of the stomata?
Veinstransport
water/food
Stomata- gas
exchange
(stem)
What is fruit?
When pollination
occurs, pollen moves
from the male parts to
the female parts.
Pollen grains land on
the stigma and a tiny
tube grows from it and
down the style into
the ovary. The
fertilized ovule
becomes the seed and
the ovary becomes the
fruit.
Seeds
• Function: to hold,
protect, and feed the
embryo
• Dispersal:
– Wind
• ex.: “helicopters”
(food for embryo)
– Animals
• Ex.: burrs, eat & excrete