Published on: Mar 3, 2016
Transcripts - Kingdom plant
Licda. Aracelis Torres
Through photosynthesis,plants convert energy fromsunlight into food stored ascarbohydrates. Becauseanimals cannot get energydirectly from the sun, theymust eat plants (or otheranimals that have had avegetarian meal) to survive.Plants also provide theoxygen humans and animalsbreathe, because plants usecarbon dioxide forphotosynthesis and releaseoxygen into the atmosphere.
Plants are found on land, inoceans, and in fresh water. Theyhave been on Earth for millionsof years. Plants were on Earthbefore animals and currentlynumber about 260,000 species.Three features distinguish plantsfrom animals:Plants have chlorophyll, agreen pigment necessary forphotosynthesis;Their cell walls are madesturdy by a material calledcellulose; andThey are fixed in one place(they don’t move).
In order to study thebillions of differentorganisms living on earth,biologists have sorted andclassified them based ontheir similarities anddifferences. This systemof classification is alsocalled a taxonomy andusually features bothEnglish and Latin namesfor the different divisions.
All plants are included in oneso-called kingdom (KingdomPlantae), which is then brokendown into smaller and smallerdivisions based on severalcharacteristics, including:Whether they can circulatefluids (like rainwater) throughtheir bodies or need to absorbthem from the moisture thatsurrounds them.How they reproduce (e.g., byspores or different kinds ofseeds); andTheir size or stature.
The majority of the 260,000plant species are floweringherbs. To describe all plantspecies, the following divisions(or phyla) are most commonlyused to sort them. The firstgrouping is made up of plantsthat are non-vascular; theycannot circulate rainwaterthrough their stems and leavesbut must absorb it from theenvironment that surroundsthem. The remaining plantspecies are all vascular (theyhave a system for circulatingfluids). This larger group is thensplit into two groups: one thatreproduces from spores ratherthan seeds, and the other thatreproduces from seeds.
Mosses and “allies,” orrelated species (Bryophytaand allies)Mosses or bryophyta are non-vascular. They are animportant foundation plant forthe forest ecosystem and theyhelp prevent erosion bycarpeting the forest floor. Allbryophyte species reproduceby spores not seeds, neverhave flowers, and are foundgrowing on the ground, onrocks, and on other plants.
Originally grouped as a singledivision or phylum, the 24,000bryophyte species are nowgrouped in three divisions:Mosses (Bryophyta),Liverworts (Hepatophyta),andHornworts(Anthocerotophyta).Also included among the non-vascular plants isChlorophyta, a kind of fresh-water algae.
Ferns and allies (Pteridophyta andallies)Unlike mosses, ferns and relatedspecies have a vascular system,but like mosses, they reproducefrom spores rather than seeds. Theferns are the most plentiful plantdivision in this group, with 12,000species. Other divisions (the fernallies) include Club mosses orLycopods (Lycopodiophyta) with1,000 species, Horsetails(Equisetophyta) with 40 species,and Whisk ferns (Psilophyta) with 3species.
Conifers and allies (Coniferophyta and allies)Conifers and allies (Coniferophyta andallies) Conifers reproduce from seeds, butunlike plants like blueberry bushes orflowers where the fruit or flower surroundsthe seed, conifer seeds (usually cones) are“naked.” In addition to having cones,conifers are trees or shrubs that neverhave flowers and that have needle-likeleaves. Included among conifers are about600 species including pines, firs, spruces,cedars, junipers, and yew. The coniferallies include three small divisions withfewer than 200 species all together: Ginko(Ginkophyta) made up of a single species,the maidenhair tree; the palm-like Cycads(Cycadophyta), and herb-like plants thatbear cones (Gnetophyta) such as Mormontea.