Plant%20Growth%20and%20Reproduction - PowerPoint PPT Presentation

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Plant%20Growth%20and%20Reproduction

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Plant Growth and Reproduction Chapter 2, Lesson 7 – PowerPoint PPT presentation

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Title: Plant%20Growth%20and%20Reproduction


1
Plant Growth and Reproduction

  • Chapter 2, Lesson 7


2
Seeds
  • A seed is an un-developed plant with stored food
    sealed in a protective covering known as a seed
    coat.

3
Germination
  • The process of a seed sprouting into a new plant.

4
Germination
  • These are different stages in the germination
    process.

5
Seedling
  • A young plant that grows and develops from a
    seed.
  • All seeds grow from a seed to a seedling to an
    adult plant.

6
Seedling
  • Most seeds swell as they take in water.
  • The seed coat splits open.
  • A root grows out of the seed.
  • Then a tiny stem appears.

7
Seedling
  • One or two leaves grow from the stem, and the
    young seedling beings to grow.
  • If the condition are just right, the seedling
    will mature into an adult plant.
  • Then it will make seeds of its own.

8
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9
Seedling
  • In some plants the time from seed to adult takes
    only days.
  • A bean plant matures in just a few months.
  • A peach seed takes several years to become a
    tree.

10
Life Cycle of a Peach Tree
11
Parts of a Seed
  • In order for a seed to germinate (the process of
    a seed sprouting into a new plant) it needs.
  • A seed must move from the flower to a place where
    it can sprout.
  • Most seeds need water and warm temperatures to
    germinate.

12
Parts of a Seed
  • Once the seedling begins to grow, it needs the
    right amount of light.
  • The leaves of the growing plant need light to
    make oxygen.
  • A seedling also needs oxygen from the air and
    nutrients from the soil.

13
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14
Pollen
  • Male sex cells are found in the pollen.
  • The pollen grains are like a soft powder.

15
Anther
  • The pollen is produced by the anthers.

Pollen
Anther
16
Pistil
The female sex cells (eggs) are found in the
pistil.
17
Pollination
  • The transfer of a pollen grain to the pistil.
  • Plants rely on insects, birds, mammals, wind, or
    water to help with pollination.

18
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19
  • This is a flower.
  • The pistil is the tall green stalk.
  • This illustration does not reflect the anthers.

20
  • A pollinator comes and deposits pollen which
    lands on the pistil.
  • How does that help?
  • A bee might go to one flower and get a little
    pollen on its back. If it goes to another flower
    of the same species, that pollen can land on the
    pistil.

21
  • Pollen grains (yellow) are located on the top of
    the pistil.
  • The pollen then travels down the pollen tube
    (yellow) until it reaches the ovaries.

22
  • The ovary then fertilizes the egg.
  • Fertilization is the joining of a female sex cell
    and a male sex cell into one cell.

23
Ovary
  • The ovary is a structure containing egg cells.
  • It is the ovary that grows to produce the
    protective fruit.

24
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25
How Are Seeds Carried Away?
  • Once a seed forms, it needs a place to grow.
  • The best chance of survival is to be in its own
    space, away from the parent plant. Why?
  • A parent plant may soak up water and nutrients
    the seedling needs from the soil.

26
How Are Seeds Carried Away?
  • Therefore, a seeds best chance of survival is
    when it is carried away, or dispersed, from the
    parent.
  • Seeds disperse in many different ways.

27
How Are Seeds Carried Away?
  • Some plants scatter their own seeds.
  • The protective, fleshy fruits explode to shoot
    their seeds away from the parent plant.
  • Pea and bean plants keep their seeds in a pod.
    When the seeds are ripe and the pod has dried,
    the pod burst open and peas and beans are
    scattered.

28
How Are Seeds Carried Away?
  • Many seeds are carried by animals.
  • The fleshy fruit may attract animals that eat the
    seeds along with the fruit.
  • The seeds may fall to the ground as the animals
    eat the fruit.
  • If the seeds are eaten, the animals will pass
    them out in their droppings.

29
How Are Seeds Carried Away?
  • Other seeds are carried by the wind or water.
  • A dandelion seeds have a parachute of feathery
    hairs.
  • They are light enough for the wind to carry them
    long distances.

30
How Are Seeds Carried Away?
  • Seeds may also become attached to humans
    clothing and shoes.

31
How Are Seeds Carried Away?
  • Some seeds may also hitch a ride on an animals
    fur and fall off in some new place.

32
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33
The Life Cycle of Flowering Plants
34
Ferns
  • Ferns are green plants which can capture energy
    from the sun through photosynthesis.
  • They do not have seeds, but instead simply use
    spores to reproduce.

35
Moss Plants
  • Do not produce flowers.
  • Do not produce seeds.
  • They reproduce by creating spores.

36
Spores
  • A spore is a cell in a seedless plant.
  • Plants such as mosses and ferns use spores to
    reproduce.
  • Spores do not have sex cells.
  • Each spore is produced by the parent plant.
  • The parent plant sheds the spores locally.
  • The spore-generating organs are frequently
    located on the undersides of leaves.

37
Moss Spores
  • The egg is fertilized.
  • The fertilized egg grows into a thin stalk with
    a spore case on top.
  • The spore case opens, the spores are released.
  • Spores land on damp ground and may grow into new
    moss plants.
  • The life cycle begins again.

38
Fern Spores
  • On a fern, spores are found on the bottom side of
    the leaf.
  • As the spore case matures and ripen, millions of
    spores are released and scattered into the air.
  • When carried by wind currents, a small number of
    them fall on damp surfaces and soils.
  • Here they form into a small, flat, kidney-shaped
    body.

39
Fern Spores
  • This body gets its food by
  • pushing roots into the soil.
  • Eventually, this plant body
  • grows male and female
  • organs.
  • Sperm from the male organ
  • fertilizes an egg from the
  • female organ.
  • This produces a new plant.
  • The new plant produces spores,
  • and the process begins again.

40
Fern Spores
  • The yellow spores are unopened. The brown spores
    are opened.

41
The End
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