plant diversity. plants have an alternation of generations: the diploid spore-producing plant...
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Plants have an alternation of generations: the diploid spore-producing plant (sporophyte) alternates with the haploid gamete-producing plant (gametophyte).
ANGIOSPERMS (flowering plants)FLOWER SEED FLOWER AGAIN*Bright colored petals/attractive scent attract*Flower has many parts*Sepal, petals, stamen, stigma, ovary
SepalsThe sepals protect the flower before it opens.sepal
PetalsThe petals attract pollinating insects with their bright colour and attractive scent.
StamensThe stamens are the male part of the flower.The plant makes pollen in the top part of the stamen, called the anther.
The StigmaThe stigma is the top of the female part of the flower.The pollen from another flower collects on the stigmas sticky surface.
The ovary protects the ovules.Pollen travels to the ovules and fertilization takes place.Now the ovules will develop into seeds.
PollinationInsects visit flowers to search for nectar their food.But the flowers use the insects for their own purposes!
As the insect probes for nectar, its body rubs against the stamens. Pollen gets stuck on the insects legs.You can often see bees with a heavy load of yellow pollen on their hind legs.
Pollination When the insect visits another flower of the same type, the pollen will stick to the stigma.This is calledpollination.
The pollen travels to the ovary, where it joins with an ovule. This is called fertilization.
SeedsThe seeds develop inside the ovary, which grows to become the seed pod or fruit.
Seed DispersalThe seeds are dispersed; some by animals, some by the wind, some by explosion and some by water.
Angiosperms have 2 divisions
Angiosperm Life CycleThe sporophyte is the dominant generation, but multicellular male and female gametophytes are produced within the flowers of the sporophyte. Cells of the microsporangium within the anther undergo meiosis to produce microspores. Subsequent mitotic divisions are limited, but the end result is a multicellular pollen grain. The megasporangium is protected by two layers of integuments and the ovary wall. Within the megasporangium, meiosis yields four megasporesthree small and one large. Only the large megaspore survives to produce the embryo sac. Fertilization occurs when the pollen germinates and the pollen tube grows toward the embryo sac. The sporophyte generation may be maintained in a dormant state, protected by the seed coat
GymnospermsGymnosperms include gnetophytes, cycads, ginkgoes, and conifersCone bearing plants
BryophytesBryophytes have life cycles that depend on water for reproduction. Lacking vascular tissue, these plants can draw up water by osmosis only a few centimeters above the ground they are low-growing plants that can be found in moist, shaded areas. mosses, liverworts, and hornworts
Bryophyte Life Cycle
Seedless Vascular PlantsFerns & Horsetails Like other vascular plants, ferns and their relatives have true roots, leaves, and stems. Roots are underground organs that absorb water and minerals
Seedless Vascular Plants Life Cycle
b. Sporophyte c. megaspores d. microsporesseedzygotesporophytemicrosporesmegasporemicrogametophyteMegagametophyteOvaryanther
EpidermisPalisade mesophyllLeaf veinSpongy mesophyllEpidermisStomateGuard cellLeaf veinsCuticleStomatesPalisade mesophyllSpongy mesophyllA, B and C
Zone of cell divisionZone of elongationZone of maturationendodermispericyclephloemxylemcortexepidermisRoot hairVascular cylinderRoot cap
The sun causes water to evaporate at leavesNegative pressureWater molecules cling to one another (cohesion) and to sides of vessels (adhesion)Negative pressure potentialCohesion refers to water molecules clinging together and tension refers to negative pressure potential. Water flows upward along the length of the plant
Plant Adaptations to Life On LandDrying out: waterproof surfacesGas exchange: stomata (above ground)/swim bladderSupport: vacuole/cell wallsConduction: xylem and phloem/conducting cellsReproduction: moist surfaces/specialized delivery systems (pollen tubes)