Plant and Animal Communities Physical Environment (1964)

[Music] all forms of life are affected by certain Natural Factors these factors form physical environment the four factors of physical environment we'll consider are altitude and atmospheric conditions heat and light water and soil conditions these factors influence any plant animal community or biome the biome changes as the physical environment changes in some regions there is an abundance of water in others there may be little water in some regions rich soil supports abundant plant life in others poor soil supports much less plant life of the many biomes we'll examine those of a deciduous forest a coniferous Mountain Forest a grassland and a desert in relation to these factors of physical environment altitude and atmospheric conditions heat and light water and soil conditions we'll begin with the deciduous forest deciduous forests are common where the physical environment includes soil classified as heavy LOM heavy LOM is rich in essential chemicals and organic materials another factor of physical environment favorable to deciduous forests is a moderate altitude approximately 1,00 to 2500 ft above sea level depending on geographic location at this altitude atmospheric conditions are generally such that there is abundant rainfall during most of the Year these physical conditions produce trees such as Beach Maple Hickory and Oak these trees need sufficient water in order to thrive because of their relatively shallow root systems and because of their large overall Leaf surface which results in Rapid evaporation of water in some parts of the forest thickly growing leaves cut down the amount of sunlight and heat reaching the forest floor thus areas of the forest floor are shady cool and moist this type of physical environment is suitable for several speci species of plants Mosses are among the many smaller plants that thrive on the deciduous forest floor others are ferns and where there is least heat and light mushrooms and other fungi many species of small animals such as millipedes live on the deciduous forest floor these are among the hundreds of species of arthopods found in this en environment other arthropods are Beatles and moths vertebrates are also found on the deciduous forest floor among the most common are the box turtle the salamander and the raccoon above the forest floor where there is more heat and light are a variety of tree dwelling vertebrates such as the squirrel and many different species of birds such as the Red shouldered Hawk thus the animal and plant population of the deciduous forest is influenced by low to medium altitude variable heat and light abundant rainfall and heavy LOM soil now let's consider another biome the coniferous Mountain Forest on a mountain slope there are several biomes the physical factor of altitude greatly influences these biomes this coniferous forest biome is at an altitude of 5 to 10,000 ft the Trees of this biome are of the fur and Spruce families the average rainfall over the years is less than that of lower altitudes the soil is is classified as rocky rocky soil is fairly shallow and rich in minerals these physical factors are especially suited to the growth of coniferous trees whose narrow leaves tend to reduce evaporation of needed moisture another way coniferous trees gain needed moisture is through their strong well-developed roots which push down through the rocky soil to reach moisture in open areas of the coniferous forest floor are found certain species of grass and other plants which can subsist on light rainfall the plant population of the coniferous Mountain Forest provides an adequate food supply for elk and other grazing animals which are adapted to the cool dry climate of this physical environment these herbivores are prayed upon by Bobcats and other carnivores that are the members of the plant animal community of the coniferous forest the physical environment M that affects this biome includes high altitude and cool climate moderate amounts of heat and sunlight moderate rainfall rocky soil let's see how these factors differ in our third biome a grassland this grassland region is in the Western United States and is situated at a moderate altitude about 4 or 5,000 ft our other environmental factors of this grassland are a temperate climate and light rainfall and a light soil adequate in essential chemicals but probably the most important of the environmental factors here is abundant light grasses Thrive best where there is plenty of light and moderate rainfall in this flat bright relatively dry environment live animals such as the antelope which are adapted to running across the flat land animals with other adaptations for protection are the prairie dog which can Burrow under the ground for safety and the harvest mouse which is camouflaged by its protective coloration these adaptations are protection against such sharp eyed fleet-- wied predators of the community as the marshhawk the physical environment of a grassland biome includes moderate altitude and temperate climate abundant amounts of heat and light a light rainfall and light soil the more abundant plant life of the grassland biome contrasts with the sparse plant life of the desert in the United States desert biomes tend to be produced in those regions where there are the physical factors of low altitudes and extremes of heat and light other factors of environment include atmospheric conditions which produce a very light rainfall the soil classified as extremely shallow has been produced mainly by erosion the shallow soil of the desert lacks some essential chemicals and does not retain much water this environment gives rise to Cactus and other plants with deep root systems in this exhibit we can see the roots of a cactus plant sometimes these roots extend 20 or 30 ft to obtain water and essential chemicals water so scarce in this environment is consumed by plants which have extremely small leaves sometimes no more than spines to reduce leaf or evaporation surface the desert biome also includes many forms of animal life adapted to hot dry surroundings there are numerous reptils such as the desert tortoise and the hila monster which have dry skins that conserve moisture some desert mammals such as the kangaroo rat obtain water from seeds and other parts of plants to find protection from the extreme heat most desert animals such as the Kit Fox remain in their cool dark dens underground this is another protective adaptation against the high daylight temperatures of the desert environment the population of the desert biome then is adapted in terms of physical environment to low altitude and arid climate excessive heat and light extremely light rainfall and shallow soil in each of the four biomes s we have examined the deciduous forest the coniferous Mountain slope Forest the grassland and the desert we have seen that physical environment influences the infinite forms of life both plant and animal and provides these living things with the substances necessary to sustain life [Music] [Applause] f