Big Idea

Science Standard 7.2.a:
Students know the differences between the life cycle and reproduction methods of sexual and asexual organisms.
Science Standard 7.5.f:
Students know the structures and processes by which flowering plants generate pollen, ovules, seeds, and fruit.

 Gymnosperm – a seed plant that produces naked seeds.
 Cones – gymnosperms reproductive structures.
 Ovule – a structure that contains an ovum, or egg cell.
 Angiosperm – a flowering plant.
 Flower – the reproductive structure of an angiosperm.

 Sepals – a leaflike structure that encloses a flower when it is still a bud.
 Petals – The most colorful parts of the flower.
 Pollination – the transfer of pollen from a male reproductive structure to a female reproductive structure.
 Stamens – a flowers male reproductive structures.

 Pistils – a flowers female reproductive structures.
 Ovary – protects the seeds as they develop.
 Fruit – a ripened ovary and other structures that enclose on or more seeds.
 Monocots – angiosperms that have only one seed leaf.
 Dicots – angiosperms that have two seed leaves.

 All gymnosperms produce naked seeds. Many gymnosperms have needle-like or scalelike leaves, and deep growing root systems.
 Gymnosperms produce seeds that are not enclosed be fruits.
 Gymnosperms are the oldest type of seed plants. (first appeared on earth about 360 million years ago.
 Only four groups of gymnosperms exist today. (cycads, conifers, ginkgoes, and gnetophytes)

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 175 million years ago, the majority of plants were cycads
 Grow mainly in the tropical and subtropical areas
 Look like palm trees with cones, and cones can grow as large a a football
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 The largest and most diverse group of gymnosperms today.
 They are cone bearing
 Keep their leaves/needles all year long
 Pines, sequoias, and junipers

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 Only one species exist today (ginko biloba)
 Planted along city streets because they can tolerate air pollution
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 Live in hot deserts and tropical rainforests.
 Consists of trees, shrubs and vines

 Most gymnosperms have reproductive structures called cones.
 Most gymnosperms produce two types of cones. Male cones and female cones.
 Male cones produce tiny grains of pollenthe male gametophyte. The pollen contains the cells that later become sperm cells
 Each scale on a male cone produces thousands of pollen grains.

 The female gametophyte develops in structures called ovules.
 Female cones contain at least one ovule at the base of each scale. After fertilization occurs the ovule develops into a seed.
 Pollen falls from a male cone onto a female cone. A sperm cell and egg cell join together in an ovule on the female cone.

 During development, cells become fixed – or setin how they will differentiate.
 The instructions that will determine what will happen is coded in the DNA in its nucleus.
 Differentiation occurs when certain sections of
DNA are turned off. The active DNA then guides the development of the cell.
 Once a cell’s future has been determined, when and how much it will changes depends on its DNA, its function, and the type of organism.
 Some cells differentiate completely during development, others do not change until later.

 Once human cells differentiate, they usually lose their ability to become other types of cells.
 Ex: a blood cell CANNOT change into a skin cell
 Humans do produce cells called STEM CELLS that can differentiate throughout life.
 Stem Cells exist all around the body, and respond to specific needs in the body by becoming specialized.
 EX: production of red and white blood cells.

 All angiosperms share two important traits.
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They produce flowers
In contrast with gymnosperms, which produce uncovered seeds, angiosperms produce seeds that are enclosed in fruits.
 Angiosperms live almost everywhere on earth.
They grow in frozen areas in the Arctic, tropical jungles, barren deserts, and at the oceans edge.
 unlike gymnosperms, angiosperms produce fruit.

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Across Discipline: Language Arts
(compare and contrast the life cycles of a gymnosperm and angiosperm)
Patterns: Draw and label The Structure of a flower (page 393)
Question: Write a question and answer it.
Different Perspectives: The differences in cell differentiation from an animal cell and plant cell
Summary: Write a summary of what you have learned.

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Across Discipline: Language Arts
(compare and contrast the life cycles of a gymnosperm and angiosperm)
Patterns: Draw and label The Structure of a flower (page 393)
Question: Write two questions and answer them.
Different Perspectives: The differences in cell differentiation from an animal cell and plant cell
Summary: Write a summary of what you have learned.