ESO 1 Science 8

The Plant Kingdom

What to Learn

  • Common features.
  • Main morphological types.
  • Main organs.
  • Main groups: bryophytes, pterydophytes, gymnosperms and angiosperms.
  • Nutrition: photosynthesis vs. respiration; role in the carbon cycle.
  • Basic interaction mechanisms.
  • Reproduction in angiosperms.

Key Information

Vocabulary: Types of Plants
BryophytesTerrestrial plants that lack a vascular system, are dependent on environmental moisture for reproductive and nutritive functions, and that disperse spores for reproduction. The group includes mosses, liverworts and hornworts.
TracheophytesPlants with a vascular system that helps them to stay upright and transports the sap, the plants' nutritive liquid mixture. The vascular system is made up of the vascular tissues xylem and phloem. The group includes pteridophytes and flowering plants.
PteridophytesTerrestrial plants with a vascular system that are dependent on environmental moisture for reproductive and nutritive functions and that disperse spores for reproduction. The group includes ferns and horsetails.
Flowering plantsOr seed plants. Plants with a vascular system that are not dependent on environmental moisture for reproductive and nutritive functions and that disperse seeds produced inside flowers for reproduction. The group includes gymnosperms and angiosperms.
GymnospermsVascular flowering plants in which the ovules are not protected by an ovary. As they don't have ovaries, they don't have fruits neither, but cones instead. Their flowers are not very conspicuous, as they lack petals and sepals. They are woody and most of them belong in the conifers (such as the pines, cedar-trees, fir-trees, spruces and cypresses).
AngiospermsA vascular flowering plant in which the ovules are enclosed inside protective ovaries and the seeds inside fruits. They use to have well-visible flowers that, when complete, are made up of sepals, petals, stamens and pistils. They can be herbaceous (like the poppy) or woody (like the oak).
Vocabulary: Leaves
LeafIt is the photosynthesis and transpiration organ in plants. Its two main parts are usually the petiole (a slender stem that supports the blade) and the blade (the green and usually flat area, with a midrib and secondary veins). When they have one only blade, they are called "simple leaves", whereas if they have several leaflets (each one resembling a single leaf with its petiole and its blade) they are called "compound leaves". You can tell whether something is a leaf or just a leaflet by watching the stipules: two membranes that are always at the base of the leaf, and never in the base of a leaflet. Holm-oaks have simple leaves, while ash-trees have compound leaves.
PalmateCompound leaves can be palmate, resembling a hand, with the leaflets outspread.
PinnateCompound leaves can be pinnate, resembling a feather, with the leaflets arranged on both sides of a central axis.
WhorlTwo or more leaves or other structures surrounding a stem at the same point.
BractA leaf associated with the flowers or inflorescences of a plant. Bracts are usually different in appearance to the other leaves on the plant. The lime-tree has very conspicuous elongated, narrow and pale-green bracts.
InvolucreA whorl of bracts, often cup-like, at the base of a flower, an inflorescence or a fruit. Daisies have involucres at the base of their inflorescences, and oaks have involucres at the base of the acorns.
DeciduousTo fall off or shed seasonally; usually refers to the leaves of a plant. It's opposite to evergreen. A poplar has deciduous leaves, while a holm-oak is evergreen.
Mind Map: Dicotomous key of leaves
[Source]

Movies, Animations and Audios

Biology of Plants
Adaptations of plants

Adaptations of plants

Learn how plants have evolved to perform efficiently the vital functions.

Produced by Britannica.com

Adaptations of leaves

Adaptations of leaves

Watch how the plants' leaves can be strongly modified to help improve a plant's adaptation to an specific environment or lifestyle.

An Assignment Discovery video

Swedish spruce is world's oldest tree

Swedish spruce is world's oldest tree

A 60-second Science podcast.

Streamed from Scientific American

Images

Common Trees
Maritime pine (<i>Pinus pinaster</i>)Maritime pine (Pinus pinaster)Stone pine (<i>Pinus pinea</i>)Stone pine (Pinus pinea)Stone pine (<i>Pinus pinea</i>) - BarkStone pine (Pinus pinea) - BarkStone pine (<i>Pinus pinea</i>) - LeavesStone pine (Pinus pinea) - LeavesStone pine (<i>Pinus pinea</i>) - Expanding shoot in springStone pine (Pinus pinea) - Expanding shoot in springStone pine (<i>Pinus pinea</i>) - Closed female coneStone pine (Pinus pinea) - Closed female coneStone pine (<i>Pinus pinea</i>) - Open female coneStone pine (Pinus pinea) - Open female conePinecone openingPinecone openingStone pine (<i>Pinus pinea</i>) - Scale from female coneStone pine (Pinus pinea) - Scale from female coneStone pine (<i>Pinus pinea</i>) - Male conesStone pine (Pinus pinea) - Male conesNorway spruce (<i>Picea abies</i>)Norway spruce (Picea abies)Norway spruce (<i>Picea abies</i>) - ShootNorway spruce (Picea abies) - ShootNorway spruce (<i>Picea abies</i>) - Open female coneNorway spruce (Picea abies) - Open female coneLebanon cedar (<i>Cedrus libani</i>)Lebanon cedar (Cedrus libani)Atlas cedar (<i>Cedrus atlantica</i>)Atlas cedar (Cedrus atlantica)Atlas cedar (<i>Cedrus atlantica</i>) - Foliage and female coneAtlas cedar (Cedrus atlantica) - Foliage and female coneAtlas cedar (<i>Cedrus atlantica</i>) - Foliage and male conesAtlas cedar (Cedrus atlantica) - Foliage and male conesEuropean yew (<i>Taxus baccata</i>): cone and leavesEuropean yew (Taxus baccata): cone and leavesMediterranean cypress (<i>Cupressus sempervirens</i>): scale-like leaves and conesMediterranean cypress (Cupressus sempervirens): scale-like leaves and conesCommon juniper (<i>Juniperus communis</i>): needle-like leaves and conesCommon juniper (Juniperus communis): needle-like leaves and cones<i>Sequoiadendron</i>: the General Grant treeSequoiadendron: the General Grant tree<i>Gingko biloba</i> (I)Gingko biloba (I)<i>Gingko biloba</i> (II)Gingko biloba (II)Beech (<i>Fagus sylvatica</i>) - ForestBeech (Fagus sylvatica) - ForestBeech (<i>Fagus sylvatica</i>) - FoliageBeech (Fagus sylvatica) - FoliageBeech (<i>Fagus sylvatica</i>) - Leaves and beechnutsBeech (Fagus sylvatica) - Leaves and beechnutsPedunculate oak (<i>Quercus robur</i>)Pedunculate oak (Quercus robur)Pyrenean oak (<i>Quercus pyrenaica</i>)Pyrenean oak (Quercus pyrenaica)Holm oak (<i>Quercus ilex</i>)Holm oak (Quercus ilex)Cork oak (<i>Quercus suber</i>) - LeavesCork oak (Quercus suber) - LeavesCork oak (<i>Quercus suber</i>) - AcornsCork oak (Quercus suber) - AcornsCork oak (<i>Quercus suber</i>) - Harvested barkCork oak (Quercus suber) - Harvested barkBlack poplar (<i>Populus nigra</i>)Black poplar (Populus nigra)Black poplar (<i>Populus nigra</i>) - LeavesBlack poplar (Populus nigra) - LeavesBlack poplar (<i>Populus nigra</i>) - Burrs on barkBlack poplar (Populus nigra) - Burrs on barkWhite poplar (<i>Populus alba</i>) - Leaves and catkinsWhite poplar (Populus alba) - Leaves and catkinsWhite poplar (<i>Populus alba</i>) - LeavesWhite poplar (Populus alba) - LeavesCommon aspen (<i>Populus tremula</i>) - Leaves (I)Common aspen (Populus tremula) - Leaves (I)Common aspen (<i>Populus tremula</i>) - Leaves (II)Common aspen (Populus tremula) - Leaves (II)Weeping willow (<i>Salix sepulcralis</i>)Weeping willow (Salix sepulcralis)Weeping willow (<i>Salix sepulcralis</i>) - Leaves and catkinsWeeping willow (Salix sepulcralis) - Leaves and catkinsWhite willow (<i>Salix alba</i>)White willow (Salix alba)White willow (<i>Salix alba</i>) - LeavesWhite willow (Salix alba) - LeavesWhite willow (<i>Salix alba</i>) - CatkinWhite willow (Salix alba) - CatkinNarrow-leafed ash (<i>Fraxinus angustifolia</i>) - LeavesNarrow-leafed ash (Fraxinus angustifolia) - LeavesEuropean ash (<i>Fraxinus excelsior</i>) - LeaveEuropean ash (Fraxinus excelsior) - LeaveEuropean ash (<i>Fraxinus excelsior</i>) - SeedsEuropean ash (Fraxinus excelsior) - SeedsSilver Birch (<i>Betula pendula</i>)Silver Birch (Betula pendula)Silver Birch (<i>Betula pendula</i>) - LeavesSilver Birch (Betula pendula) - LeavesSilver Birch (<i>Betula pendula</i>) - Leaves and catkinSilver Birch (Betula pendula) - Leaves and catkinSilver Birch (<i>Betula pendula</i>) - BarkSilver Birch (Betula pendula) - BarkWych elm (<i>Ulmus glabra</i>)Wych elm (Ulmus glabra)European white elm (<i>Ulmus laevis</i>)European white elm (Ulmus laevis)Box elder maple (<i>Acer negundo</i>)Box elder maple (Acer negundo)Norway maple (<i>Acer platanoides</i>)Norway maple (Acer platanoides)Field maple (<i>Acer campestre</i>)Field maple (Acer campestre)London plane (<i>Platanus x hispanica</i>) (I)London plane (Platanus x hispanica) (I)London plane (<i>Platanus x hispanica</i>) (II)London plane (Platanus x hispanica) (II)Common privet (<i>Ligustrum vulgare</i>)Common privet (Ligustrum vulgare)White mulberry (<i>Morus alba</i>)White mulberry (Morus alba)Black mulberry (<i>Morus nigra</i>)Black mulberry (Morus nigra)Mimosa (<i>Acacia dealbata</i>) (I)Mimosa (Acacia dealbata) (I)Mimosa (<i>Acacia dealbata</i>) (II)Mimosa (Acacia dealbata) (II)Common dogwood (<i>Cornus sanguinea</i>) (I)Common dogwood (Cornus sanguinea) (I)Common dogwood (<i>Cornus sanguinea</i>) (II)Common dogwood (Cornus sanguinea) (II)

Activities

Do it yourself: Making a Plant Collection
[Adapted from The University of Arizona]
What is it?

When scientists preserve a specimen of a plant (or part of a plant) they usually flatten it, dry it, and mount it on special paper. Preserved in this way the plant specimen can be stored for many years without falling apart.

Before you start

Before collecting plants in the wild, you should understand the legal issues of the ownership of the land and its resources, and the ethical issues of possible damage to wild plant populations and to endangered species. It is legal to collect plants only with the permission of the owner of the property on which they are found.

What to collect

Picking a few leaves or flowers usually does not give a representative picture of a plant. Pieces of specimen plant material need to be large enough to show the characteristics of normal growth and development. Taking a branch, stem or even the entire plant may be required to get a good specimen. If the plant is small, take the whole thing, roots and all, or even several of them. If large, get a branch about 25 cm long, with leaves, flowers, and fruits, if possible. A "sterile" specimen (one with leaves only) may be impossible to identify. Even an old empty seed capsule can be helpful if that's all you can find.

Information needed

The date the plant was collected and the location as exactly as possible. Record anything that the specimen won't show, for example, the size of the plant, flower colour, whether the plant is woody or not, etc. Note what kind of a place the plant was found, e.g., in gravel at stream edge, in shade under live oaks, in a sidewalk crack…

How to press a plant

Place the specimens between newspaper sheets and write the name of the species alongside. Alternatively, you can separate the specimens with corrugated cardboard (for air circulation) and blotter paper or paper towels to absorb moisture. Arrange the plant so that all parts show (for example, don't put the flowers between layers of leaves). Place the stack between boards and strap them tightly or place a heavy weight on top (such as a pile of heavy books). Put the stack where there is good air circulation, but not too much heat: you don't want to cook them.

Examine the plants daily and change newspapers or blotters when they become too wet. Remove plants from the stack when they are dry. You can kill insects in dried plant specimens by freezing them for three or four days, and keep them pest-free in a tightly sealed plastic bag.

The herbarium

Once the plants are dry enough, stick each specimen in a cardboard folder. Label them writing their Latin (scientific) and English names, along with all the other data that you previously recorded (collection date and place, description of the specimen...).