Lecture VII. Biomes: Kinds Of Ecosystem. BiomEs.
Kinds Of Ecosystem
1.Cool Deserts - These are dominated by sagebrush, rabbitbrush and smallerperenial plants.
2.Hot Deserts– these are dominated by creosote, cacti, acacias, agave, and yucca.
Desertsoilislargerlyunprotected by vegetation. It issubject to severeerosionfromwind and occasionalrain. It has a thin top layer of decaying plant materialscalledhumus.
Grasslands are dominated by grasses, and a richarray of deep-prooted, beautifullyflowering non grasses species. They have a few treesbecause of inadequate and freuentgrassfirethatkillswoodyseedlings.
Forest are regionswheretreesgrow as a result of adequatetemperature and minimal precipitation of 75 centimeters or more.
1. Tropical Rainforest – the forestwithhigh, fairly constant rainfall and temperaurethat permit trees to growthroughout the year. Annualrainfallmayexceed 400 cm. This is the biome with the highestspecisdiversity. The number of species in a given area may have almost 100 differentspecies per hectare.
2. Tropical seasonalforestisalsoknown as monsoonforest.Seasonalrainfallisconcentratedduring a certain part of the yearafterwhichfollows an increasinglypronounced dry season.
3. Tropical savannaconsist of grasslanddottedwithscatteredsmalltrees and shrubssuch as acacias. Somesavannas are entirelygrassland; otherscontainmanytrees.
4. Tropical thornwood, shrubland and tropical shrub. The proportion of treesdepends on the competitionbetweentrees and grasses for water. The oilis more fertile thanmost tropical rainforest, but the rainfalliserratic.
2. Temperate evergreen forest occurs where condition favors conifers or broad-leave evergreen over decidous trees. I has poor soil condition, frequent droughts and forest fires. The temperate evergreen plants include ponderosa and pine trees. These forest are found in Eastern Asia, Southern Chile, New zealand and Australia.
4. Temperate woodland ocurrs where the climate is too dry to support a forest yet provides sufficient moisture to support trees as well as grasses. Dominant trees are conifers, evergreen, flowering trees, or decidous trees.
The term “taiga” comes from the russian word meaning “primeval forest”. It is also known as boreal forest. It is dominated by conifers that can survive extreme cold in winter. The trees in taiga are further apart than in he forest and enough sunlight penetrates the forest floor to support an extensive ground cover for the shrubs. Most taiga precipitations are snow.
The tundra is a treeless biome that occurs far north in the Arctic regions where winters are too dry and cold to permit the growth of trees.
5. Metabolic Waste- all organisms produce metabolic waste products. Plants release oxygen by day, give off carbon dioxide by night, and discard leaves and stems on a seasonal basis.