Sexual Sexual Reproduction in Reproduction in

PlantsPlants

Sexual Reproduction – Sexual Reproduction – Plants!Plants!

Cycle that allows plants to Cycle that allows plants to reproduce sexually is the same as in reproduce sexually is the same as in animals. animals.

Seeds are the products of sexual Seeds are the products of sexual reproduction in most plants.reproduction in most plants.

SeedSeed – contains an embryo, a food – contains an embryo, a food supply, and a seed coat, which supply, and a seed coat, which protects the seed from drying out. protects the seed from drying out.

Plants!Plants!

Seed-producing plants can be Seed-producing plants can be divided into 2 groups:divided into 2 groups:

1.1. Angiosperms Angiosperms – enclosed seed– enclosed seed

2.2. Gymnosperms – Gymnosperms – naked seednaked seed

AngiospermsAngiosperms Flowering plantsFlowering plants Seeds form inside the flowerSeeds form inside the flower When mature, the seeds are When mature, the seeds are

enclosed in a shell, such as a pod enclosed in a shell, such as a pod or a case. or a case.

Some have showy flowers – such Some have showy flowers – such as a lily.as a lily.

Others produce very tiny Others produce very tiny flowers – such as grasses. flowers – such as grasses.

AngiospermsAngiosperms

Flowers contain the Flowers contain the reproductive organs.reproductive organs.

The female The female reproductive organ is reproductive organ is called the called the pistilpistil..

The male The male reproductive organ is reproductive organ is called the called the stamenstamen. .

Pistil Pistil

Includes:Includes: Stigma – sticky lip of the pistil that Stigma – sticky lip of the pistil that

captures pollen grainscaptures pollen grains Style – stalk that supports the stigmaStyle – stalk that supports the stigma Ovary – swollen base containing Ovary – swollen base containing

ovulesovules Ovules – sacs containing female Ovules – sacs containing female

gametesgametes

StamenStamen Includes:Includes: Anther – where the pollen is Anther – where the pollen is

produced and storedproduced and stored Pollen Grains – cases containing Pollen Grains – cases containing

male gametesmale gametes Filament – stalk the supports the Filament – stalk the supports the

antheranther

PollinationPollination

Pollination –seeds begin to develop when Pollination –seeds begin to develop when the pollen grains reach the stigma of the the pollen grains reach the stigma of the pistil. pistil.

Self- Pollination Self- Pollination - both male and female - both male and female gametes come from the same flowergametes come from the same flower

Cross – PollinationCross – Pollination - brings together - brings together gametes from different parent plants. gametes from different parent plants.

The 2 most common helpers for cross-The 2 most common helpers for cross-pollination are the wind and insectspollination are the wind and insects

PollinationPollination

Pollination is not enough to Pollination is not enough to ensure fertilization.ensure fertilization.

The pollen grains must grow a The pollen grains must grow a pollen pollen tube tube – which will grow and reach the – which will grow and reach the ovule inside the pistil. ovule inside the pistil.

Seed MaturedSeed Matured When the sperm reaches the When the sperm reaches the

egg it creates a zygote. egg it creates a zygote. The zygote will undergo The zygote will undergo

Mitosis and create a many Mitosis and create a many celled embryo with a celled embryo with a miniature leaf, root and miniature leaf, root and stem, and a case stem, and a case that surrounds it and stores food. that surrounds it and stores food.

As the seed matures it forms As the seed matures it forms a fruit – such as a pod or a case, a fruit – such as a pod or a case, around the seed. around the seed.

Seed DispersalSeed Dispersal

This increases the likelihood that This increases the likelihood that offspring will survive – as they will not offspring will survive – as they will not be competing with the parent for be competing with the parent for water, soil, and sunlight.water, soil, and sunlight.

Animals, wind, and running water help Animals, wind, and running water help with the dispersal of seeds. with the dispersal of seeds.

http://http://www.youtube.com/watch?vwww.youtube.com/watch?v=sr4Khc7BUzA=sr4Khc7BUzA

GymnospermsGymnosperms Gymnosperms produce their seeds Gymnosperms produce their seeds

inside cones – cones are the inside cones – cones are the reproductive organs.reproductive organs.

Some species will produce female and Some species will produce female and male cones on separate tress – while male cones on separate tress – while others produce both cones on the others produce both cones on the same tree.same tree.

http://http://www.youtube.com/watch?vwww.youtube.com/watch?v=p0PctCgj66Q=p0PctCgj66Q

Check your Understanding! Check your Understanding!

Answer the following questions:Answer the following questions:

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1, 4 1, 4

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2a c, 32a c, 3