Plants. Objective Students will be able to Students will be able to Describe the characteristics of plants Describe the characteristics of plants

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  • Plants

  • Objective Students will be able to

    Describe the characteristics of plants

  • An Overview of Plants

    Plants Between 260,000 and 300,000 different speciesHave adapted to almost every environment

  • An Overview of Plants

    Plants have some general characteristics:Roots or root-like structuresCan perform photosynthesisHas cells that are different from those of other organisms

  • An Overview of Plants

    Plant cellsCell walls, which provide structure and protection.Green pigment chlorophyllCentral vacuole, which regulates water content.

  • An Overview of Plants

    Earliest plants were probably green algae, dating back to 420 m.y.a.Cone-bearing plants show up around 300 m.y.a.Flowerings plants came into existence around 120 m.y.a.

  • An Overview of Plants

  • An Overview of Plants

    Scientists think plants probably evolved from green algae in the sea because:Plants and green algae have the same types of chlorophyll and carotenoids.Fossils of early plants are similar to the ancient green algae.

  • An Overview of Plants

    When plants moved to land, they had to adapt to new conditions.More sunlight and carbon dioxide were available.Plants developed a cuticlea waxy, protective layer secreted onto the surface of the plant which holds water in and allows plants to live in drier conditions.

  • An Overview of Plants

    When plants moved to land, they had to adapt to new conditions.Cell walls developed cellulose, a chemical compound that provides structure and support, which allows plants to stand upright on land.Water-resistant spores and seeds enabled plants to reproduce on land.

  • An Overview of PlantsPlant classification

    Vascular plants use tube-like structures that carry water and nutrients throughout the plant.Nonvascular plants lack tube-like structures and use other ways to move water and nutrients.

  • ObjectiveStudents will be able to:Identify seedless plants Distinguish between vascular and nonvascular seedless plantsExplain a pioneer speciesExplain how humans use seedless plants

  • Seedless Plants

    Nonvascular plantsVery small plants that have rhizoids rather than rootsSeedless Vascular plantsReproduce by spores, but have vascular tissue that carries water and nutrients throughout the plant

  • Nonvascular plantsWater is absorbed and distributed directly through cell membranes and cell walls.Grow in damp environmentsReproduce by spores rather than seeds

  • Nonvascular plantsExamples of nonvascular plants:Mosses - green, leaflike growths arranged around a central stalk

  • Nonvascular plantsExamples of nonvascular plants:Liverworts - flattened, leaflike bodies

  • Nonvascular plantsExamples of nonvascular plants:Hornworts - have only one chloroplast in each of their cells

  • Nonvascular plantsPioneer species Organisms that are the first to grow in new or disturbed areas and which change environmental conditions

  • Seedless Vascular plantsReproduce by spores, but have vascular tissue that carries water and nutrients throughout the plantCan grow bigger and thicker than nonvascular plants

  • Seedless Vascular plantsExamples of seedless vascular plantsFerns - largest group of seedless vascular plantsHave stems, leaves, and rootsLeaves are called frondsReproduce by spores found on the back of their fronds

  • Seedless Vascular plantsExamples of seedless vascular plantsClub mosses - needlelike leaves

  • Seedless Vascular plantsExamples of seedless vascular plantsHorsetails - jointed stem with a hollow center

  • Seedless plantsSeedless plants are important because they have many useful purposesFueldecaying seedless plants are compressed into peat and eventually coalSoil conditionersFerns can be used for weaving material and basketry.

  • ObjectiveStudents will be able to:Describe the characteristics of a seed plantDescribe the anatomy of a seed plantDistinguish between gymnosperms and angiospermsCompare and contrast monocots and dicotsExplain how humans use seed plants

  • Seed Plants

    Have leaves, stems, roots, and vascular tissue

    Reproduce by seeds, which contain an embryo and stored food

  • Seed PlantsLeaves Trap light and make food through photosynthesis.

  • Seed PlantsLeavesEpidermis - a thin layer of cells on the upper and lower surfaces of a leafMay have a waxy cuticle coating the epidermisStomatasmall openings in the epidermis that allow carbon dioxide, water, and oxygen to enter and exit a leaf Each stoma is surrounded by two guard cells that open and close it.

  • Seed PlantsLeavesPalisade layer - contains chloroplasts, where most food is madeSpongy layer - loosely arranged cells and air

  • Seed PlantsStems allow the movement of materials between leaves and roots.Usually above groundSupport the branches, leaves, and flowersMay store food

  • Seed PlantsStems:

    Herbaceous stemssoft and green

    Woody stemshard, rigid, and woody

  • Seed PlantsRootsRoots collect water and nutrients from the ground.Roots anchor plants so they dont blow away.May store food or water.

  • Seed PlantsVascular tissueXylem tissuetransports water from the roots throughout the plantPhloem tissuemoves food from where it is made to other parts of the plantCambium tissueproduces new xylem and phloem cells

  • Seed PlantsThere are two kinds of seed plantsGymnospermsAngiosperms

  • GymnospermsVascular plants that produce seeds that are not protected by fruitOldest trees aliveGymnosperms have no flowers.Leaves are often needlelike or scalelike

  • GymnospermsFour divisions:ConifersCycadsGinkgoesGnetophytes

  • GymnospermsConifersCone-bearing, reproducing because of male and female conesWoody Most are trees, some are shrubsFirst trees on earth

  • GymnospermsConifers are the oldest living things on earth

    Left: oldest tree is a bristle-cone pine, the Methuselah tree is 4,839 years old Right: Newly discovered in Sweden, this spruce has a root system that is 9,600 years old.

  • GymnospermsConifers are the oldest living things on earth

    NOVA Online | Methuselah Tree

  • GymnospermsConifers are the tallest living things on earth

    Hyperion is the newly discovered sequoia that is 379.1 feet tall, beating out the Stratospheric Giant at 370.5 feet.

  • GymnospermsConifers are the widest living things on earth

    Left: the General Sherman Redwood at 102 ft. around Right: The Tree at Santa Maria del Tule, a Montezuma Cypress at 164 ft. in circumference

  • GymnospermsConifers are the widest living things on earth

    This is known as the Tree of a hundred horses.At 204 ft around it was the widest tree ever measuredIt now grows in three pieces

  • AngiospermsVascular plants that flower and have fruit that contains seedsFruit develops from flowers.Most fruit contains seeds.

  • AngiospermsTwo groups:

    MonocotsOne cotyledon in seedVascular bundles scatteresFlower parts in multiples of threeParallel veins on leaves

  • AngiospermsTwo groups:

    DicotsTwo cotyledons inside their seedsVascular bundles in ringsFlower parts in multiples of four or fiveBranching veins

  • AngiospermsDifferent angiosperms have different life cycles:Annual - the plants life cycle is completed within one yearBiennial - the plants life cycle is completed in two yearsPerennial - takes more than two years to grow to maturity

  • Seed PlantsSeed plants are very important because they have useful purposesWood for constructionPaper products.Angiosperms form the basis of diets for most animals, including humans.

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