sciencefor7notes Ms Shukwit
Stuart Country Day School of the Sacred Heart Science 7
Grade 7:  From Bacteria to Plants

Ch 4: Introduction to Plants
A. Plant Kingdom
...1.  What is a plant?
......a.  plants are autotrophs that produce theor own food.
......b.  all plants are eukaryotes and are multicellular
......c.   Photosynthesis is th e process by which pl ants make their own food
......d.   During photosynthesis, plants use carbondioxide and water to make oxygen and food called glucose

...2.   Plant cells
......a.  are enclosed by cell wall which surrounds cell membrane
......b.  ce l ls walls are made mostly of cellulose w hich makes wall rigir
......c.  contain chloroplasts in which glucose is made; the green chemical
............in chloroplasts  that traps sunlight is called chlorophyll
......d.  contain large vacuoles to store w a ter, waste and food
......e.  are organized into tissues, which are groups of similar cells; that means cells having same jobs

...3.  Early plants
......a.  fossil evidence indicates that the first plants were algae-like
......b.  further proof comes fro m the similarity of the chlorophyll in both green plants and algae

...4.   Adaptation for land living  (summary)
......a.  most plants live on land; therefore they need special adaptations
......b.  these adaptations include ways to:
............1.  ob ta in water and other materials from surroundings
............2.  retain (hold) water
............3.  transport materials throughout plant
............4.  support itself
............5.  reproduce

...5.    Adaptations in more detail
......a.  system o f tubes called vascular tissue allows materials to move from roots up and down plant
......b.  vascular tissue also strengthens and supports plant
......c.  cuticle is a waxy, waterproof layer on leaves to keep water from evaporating

...6.  Reproduction
......a.  plants have complex life cycles made of 2 different stages
............1.  in one stage the sporocyte produces spores
............2.  spores grow into 2nd stage called gametophyte
............3.  the gametophyte produces gametes (sex cells)
............4.  female gametes are called eggs
............5.  male gametes are called sperm


B.  Photosynthesis
..1.  Nature of light
............a.  the light we see is called white light; it contains the visible spectrum
............b.  the colors in the visible spectrum are the colors of the rainbos, ROYGBIV
(I is for indigo)
............c.  we see things as colored because some materials absorb (take in) some light waves and
..................other materials reflect (bounce back) others
............d. example:  a object we see a blue has chemicals in it that reflect blue to our eyes and keep the other light waves
............e.  the color we see something as, is the color that is reflected back to our eyes

...2.  Plants and light
............a.  l ike most other objects, plants absorb some colors and reflect others
............b.  since a plant is green, it reflects green to use and absorbs the other colors
............c.  it is the chlorophyll in the plant cell that absorbs most of the blue and re d and reflects green
............d.  other pigments (accessory) in the chloroplast reflect the yellow, orange and red colors;
..................these pigments are only seen in the fall when the chlorophyll is not produced
............e.  it is the lig ht t hat is absorbed by the chloroplasts that supply energy for the process of photosynthesis
.
...3.  The Chemistry of Photosynthesis
............a.  raw materials (things needed) >> carbon dioxide gas from air and water from soil
............b.  produc t s (th ings made) >> oxygen gas which goes into air and glucose sugar which is kept stored in the plant
............c.  the general equation (summary) for photosynthesis must be memorized:

....................................................in the prese nc e of l ight
.......................carbon    +   water     ----------------------------->  glucose    +  oxygen
.......................dioxide                       sugar

............d   since photosynthesis is the process by which autotrophs and he ter otrophs
......................obtain food (energy), this process above is probably the most important
......................one on earth

C.  Mosses, Liverworts and Hornworts
...1.  Characteristics of Nonvascular plants
......a.  these are tiny pla nts that have solved the problem of living on land by living in moist places,
............covering rocks or ground like a fuzzy green carpet
......b.  they are very small because they lack vascular tissue and therefore can only pass materials from cell t o cell
......c.  the only support they get is from their cell walls
......d.  they lack roots, but get water and nutrients from air or through rhizoids
......e.  because they live in moisture, water loss in not a great problem
......f.  reproductive cell s develop hard coats to survive drought and the sperm cells swim to the egg cells when the body of the plant is covered with rainwater or dew
......g.  be certain to be able to explain why adaptations are not needed by these plants and
............how the y have solved each problem experienced by most land plants

...2.  Mosses
......a. the most diverse of nonvascula r plants
......b. structure (p. 126) should be known
.........1)  moss gametophyte is low to ground and is the fuzzy green portion
.........2)  the gametophyte contains structures looking like stems, leaves and roots (rhizoids)
............which anchor t he moss and absorb water and nutrients
.........3) on top of the gametophyte is the sporophyte which consists of a brown stalk and capsule containing spores

...3.  Importance of mosses
......a.  Bogs
.........1.  sphagnum moss is a type of moss that grow s in wetlands called BOGS
.........2.  when the moss dies, instead of decomposing it forms thick piles at bottom of bog
.........3.  these compressed layers become brown and are called PEAT MOSS
.........4.  peat moss is used by gardeners to improve the s oil's texture and ability to hold water
.........5.  peat moss is also burned for fuel in some cultures

......b.  Pioneer plants
.........1)  moss are among the first organisms to grow in areas destroyed by volcano or fires
.........2)  any organisms tha t do this are called pioneers

...4.  Other nonvascular plants
......a.  liverworts and hornworts differ from mosses by the shape of thei r gametophytes and sporophytes
......b.  liverworts grow flat along the ground on moist soil and rocks; their gametoph ytes have somewhat the shape
............of a human liver
......c.  hornworts grow only in soil and are often found among grasses

D.  Ferns and their relatives
...1.  ferns, club mosses and horsetails have vascular tissue and produce spores
...2.  because ferns and their relatives are vascular they have true roots, stems and leaves
...3.  for ferns, stems and roots are found underground; only the leaves show on top
...4.  fern leaves are called fronds;  they have a divided-leaf structure and is coated (cuticle)
...5.  the  familiar part of fern is the sporophyte stage; spores are formed on underside of leaf
...6.  when spores are released, they fall to ground and form very small gametophytes
...7.  ferns need standing ater for their sperm cells to swim to their egg cells; they need water to reproduce
...8.  club mosses and horsetails are very similar to ferns; unfortunately, not many species survive today

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Last updated  2008/09/28 09:22:10 EDTHits  711