Plant People and Seed Plants

Plants as food

• How many different plants do we eat for food?

• Fruits – the vegetative (reproductive) part of a plant- all fruits contain seeds

• Vegetable- any other part of the plant- leaf, stem, root

Root Crops

• Rich in calories, easy to grow• Potatoes, beets, radishes, carrots, cassava• Grow underground

Legumes

• Members of the pea family• Protein-rich seeds in pods• Beans, peas, peanuts, soybeans, alfalfa• Relationships with nitrogen-fixing bacteria

that can put nitrogen back into the soil- farmers rotate crops from corn to soybeans

Cereals• Grasses that produce grains (dry, edible, fruit)• Each grain is actually a fruit that develops from a

single flower.• Each corn kernel is a single, fruit• Rich in carbohydrates• More than 70% of all cultivated ground is used for

cereals• Corn, wheat, rice= ½ human calories

Fruits and seeds

• Ovary of fertilized flower will develop into a fruit

• Fruits contain seeds– Seeds with one half- monocots– Seeds with two halves- dicots

Nonfood uses

• Rubber, latex- from rubber tree• Wood-lumber, heating, furniture…• Medicines- aspirin from willow trees– Digitalis- foxglove plant for heart disorders– Cancer treatments from periwinkle– Caffeine – Drugs

Nonfood uses

• Fibers– Paper– Cotton– Flax– Hemp

Seed-Bearing Plants• Gymnosperms- nonflowering– 4 divisions• Cycads• Ginkgos• Conifers• Gnetophytes

• Angiosperms –flowering– 2 subdivisions• Dicots• monocots

Conifers- Coniferophyta

• Pine trees• Produce true cones• Male cones are small, clustered and fleshy• Female cones are large and become woody• Leaves are needle-like

Conifers

• Leaves fall off all year long, but are continuously replaced- called evergreens

• During pollination- males release clouds of pollen that is airborne to the female cones

• Female cones are fertilized 1 year after pollination• Germination may take another year

Conifers

• Sporopohyte is the dominant generation• May grow for many years• Some are found that were growing during the

age of pharoahs

Pine Cones

Angiosperms- flowering plants

• Last group to evolve• Largest group of plants• Seeds enclosed in fruits that grow from

flowers• Flowers are used to attract pollinators• Seeds and fruits are highly valuable

Angiosperms

• By this point we have the following major advntages– Cuticle- nonvascular plants– Vascular tissues- vascular seedless– Seeds- gymnosperms– Flowers- angiosperms

• Angiosperms are at the top of the plant evolutionary tree

Angiosperm transport

• Roots- absorb nutrients and water and transport them up the plant

• Stems- support plant and transport substances up and down the plant

• Leaves- main photosynthetic organ, draws water up the plant from the roots

Flowers

• Highly specialized reproductive structures• Stamen- male part- anther + filament- produces

pollen• Pistil-female part –stigma+style+ovary+ovule-

produces eggs• Pollination occurs when pollen is delivered to the egg

Flowers

Next chapter

• Reproduction– Asexual– Sexual– Flowers– Cones

• Easy chapter!