Many Plants Reproduce With Flowers and Fruit

• ANGIOSPERMS HAVE FLOWERS AND FRUIT

• ANIMALS SPREAD BOTH POLLEN AND SEEDS

• HUMANS DEPEND ON PLANTS FOR THEIR SURVIVAL – Land animals rely on plants for food &

oxygen (and materials).

Angiosperms: Flower & Fruit• Angiosperms are seed plants that make flowers and fruit

(peanuts, grapes, strawberries, roses, grass etc,); most plants are angiosperms

• Sperm of a flowering plant are protected in a pollen grain & don’t need water to get to egg.

• Eggs develop into embryos that are enclosed within seeds.• Both angiosperm & gymnosperm have male & female

reproductive structures; sometimes on same plant or sometimes male & female plants.

• Angiosperms have sperm & egg in flowers• Flower = reproductive part of angiosperm; egg forms in ovary &

if fertilized forms seed(s) with ovary becoming fruit around the seed(s).

ANGIOSPERM FLOWER• Anther= male part (meiosis forms sperm within pollen grains)• Pistil= female part (meiosis forms egg cells within ovary)• Pollen grains released & if caught on pistil grows a pollen

tube into ovary• Sperm travels via p. tube to ovary to fertilize the egg (grows

into embryo & forms seed coat)• Ovary forms into fruit around seed(s); may fall to ground or

be eaten by animal. If lands in place where it can germinate & survive, will grow into a new plant.

• Asexual reproduction may also occur in angiosperms by root shoots or “runners” forming new plants.

Angiosperms: Flowers• Flowers vary in color, shape, size & scent. • In some species, male & female parts are on different

flowers, & sometimes separate male & female trees/plants.

• Sepals: leafy structure enclosing flower before it opens.• Petals: leafy structures around the pistil, usually

colorful (attract pollinators)• Stamen: male part including stalk (filament) and anther

tip (makes sperm inside of pollen grains)• Pistil: female part- ovary is at the base with egg cells.

Top of pistil= stigma (pollen grain attaches)

Angiosperms: Fruit• Fruit: a ripened plant

ovary, may have more than 1 seed (apple)

• Fleshy fruit has juicy flesh (cherry,corn)

• Dry fruit (nuts, wing fruit of maple tree, feathery dandelion & sunflowers). May have shells to protect them or structures to transport them.

Animals spread Pollen & Seeds• As animals eat, they move pollen from flower to flower &

seeds are transported.• Animals that pollinate flowers are pollinators. Bees are very

important ones.• Relationship between angiosperms & pollinators can be very

specific (hummingbirds with long beaks for some)• Animal pollinators bring it to where it is needed most (bee to

another flower) while wind pollination scatters it everywhere.

• Many seeds go through animals digestive tract (after fruit is eaten) & deposited in its waste (to help scatter seeds widely)

• Dry fruit seeds (burrs) catch on fur & are spread.

Humans Need Plants to Survive• Land animals rely on plants for food & oxygen (and materials).• All organisms need energy to live; animals get it via food.

Plants & algae capture energy from Sun to make sugars and oxygen (photosynthesis). Angiosperms are main food supplier & algae main oxygen supplier. Animals need oxygen to release energy stored in food.

• Plants are an important source of natural resources (natural gas/coal from plant remains under ground; soil made from rocks broken down partially by plant roots & decayed plants)

• Plants provide wood (lumber & paper) cotton (clothes) aspirin & other drugs made based on chemicals originally found in plants.