SEXUAL REPRODUCTION IN SEED PRODUCING PLANTS

All living things need to reproduce to replace ones that die.

Seed producing plants reproduce by making seeds.

Before a seed can grow into a new plant an egg with ½ the amount of chromosomes (female gamete) must join with pollen (male gamete) with the other ½ of the chromosomes to be fertilized.

GYMNOSPERMS A gymnosperm is a seed plant

that produces naked seeds - seeds that are not enclosed by a protective fruit.

They do not produce flowers. Examples of gymnosperms

are: Conifers Redwoods Fir trees Cedar Spruce

GYMNOSPERMS Most gymnosperms have reproductive structures called cones. This is where the seeds are located. Male cones produce pollen (male gamete). Female cones contain at least one ovule.

An ovule is a structure that contains an egg cell (female gamete).

After being fertilized by the pollen, the ovule develops into a seed.

The transfer of pollen from a male reproductive structure to a female reproductive structure is called pollination.

Both male and female cones can be on the same tree and are usually pollinated with help from the wind.

GYMNOSPERM REPRODUCTION

ANGIOSPERMS Pollination and fertilization take

place in the flower of the plant. The seeds are in a closed ovary unlike

in gymnosperms.

BRAIN BREAK

PARTS OF A FLOWER Petals: attract

insects by their bright color and scent.

Sepals: Green leaves around the outside of the flower. Sepals are usually smaller than the petals. Used to protect the flower while it is still in bud.

FEMALE REPRODUCTIVE PARTS (PISTIL) Stigma - sticky top

part at the top where pollen lands

Style - stalk that is in between the stigma and ovary

Ovary - where the egg (fruit) is formed

Ovule – inside the ovary, turns into seeds

MALES REPRODUCTIVE PARTS (STAMEN) Stamens: This is where pollen is made.

It is the male part of the flower. The stamen has two parts:

the filament (a thin stalk) the anther which is where pollen is made.

STRUCTURE OF THE FLOWERS (PG 277)

FYI: Male over female? Flip the peppers over to check their gender. The ones with four bumps are female. The ones with three bumps are male. The female peppers are full of seeds. You can save yourself some money by getting the males. Who knew that they were different?

ANGIOSPERM REPRODUCTION

Sexual reproduction in a flowering plant has FOUR main stages: Pollination Fertilization Seed dispersal Germination 

POLLINATION A plant is pollinated when

pollen from another flower reaches it.

Pollen is a yellow dust and it has to reach the stigma of the plant being pollinated.

The pollen has to be carried from the stamen of one flower to the stigma of another.

It is usually carried by bees (or other small animals) but it can be carried by the wind.

Pollination Types Video Clip

FERTILIZATION When the pollen and the

ovule join together to make a seed.

The seed also contains a food store, usually starch.

The part of the flower surrounding the seed is known as the fruit.

After fertilization the petals and stamens wither and die.

The ovary (which forms the fruit) swells up, sometimes considerably. (Ex:an apple) Angiosperms and Pollinators

Video

SEED DISPERSAL The job of the fruit is to carry the seeds as far as possible from the parent

plant so the new plants have room to grow and do not compete for resources such as light, water and nutrients in the soil.

A plant will disperse their seeds in many ways: 1. Animals: The fruit is eaten by animals such as birds but are not

digested. The seeds are pooped out. Ex: cherry, blackberry.

2. Explosion: The fruit splits open. Sometimes this happens with a lot of force and the seeds are shot out. Ex: beans. The pod is the fruit and the beans are the seeds.

3. Animals Again: The fruits have little hooks that stick to the fur of animals. Ex: burdock.

4. Wind: The fruits have wings or hairs and this lets them get carried by the wind. Ex: sycamore trees have winged fruits.

5. Water: The seeds are fall into moving water and are carried away.

SEED DISPERSALSeed Dispersal Video Clip

GERMINATION

Germination is the process by which the seed actually starts to grow. 

Conditions needed for germination: warmth oxygen water

Without all three (water, oxygen and warmth) the seed will not grow.