World Biomes PDF

WORLD BIOMES Biomes A biome is an area of the planet that can be classified according to the plants and animals that live in it. ○ Temperature, soil, and the amount of light and water help determine what life exists in a...

WORLD BIOMES Biomes A biome is an area of the planet that can be classified according to the plants and animals that live in it. ○ Temperature, soil, and the amount of light and water help determine what life exists in a biome. A biome is different from an ecosystem. ○ An ecosystem is the interaction of living and nonliving things in an environment. ○ A biome is a specific geographic area notable for the species living there. ○ A biome can be made up of many ecosystems. Biomes are climax communities with wide geographic distribution. The primary environmental factor that determines the kind of biome present is climate. Biomes are the fundamental pillar for the balance of nature since they correspond to certain areas or zones that, due to their geographical characteristics, share a climate, flora, and fauna. Biome is a broader term than a habitat; any biome can comprise a variety of habitats. In other words, it is a set of ecosystems where all the living beings that inhabit there are closely related to each other and to their environment. It is the climate, one of the geographical characteristics, that determines how many types of biomes exist in the world. The most recognized and studied classification biomes were terrestrial (forests, grasslands, savannas, taiga, deserts, and tundra) and aquatic (estuaries, streams, lagoons, lakes, coral reefs, oceans, seas, and wetlands). What is Climate? Climate is the average weather in an area over a long period of time, whereas weather is a day to day explanation. Weather and climate are described in terms of factors such as temperature and precipitation. The climate of a particular location depends, in turn, on its latitude (distance from the equator) and altitude (distance above sea level). Other factors that affect an area’s climate include its location relative to the ocean or mountain ranges. Temperature and moisture are the two climatic factors that most affect terrestrial biomes. 1 Fundamental Classification of Biomes TERRESTRIAL (land) BIOMES AQUATIC BIOMES Desert Freshwater biomes Forest Saltwater biomes (marine) Grassland Tundra 1.1 TERRESTRIAL BIOMES Latitudinal patterns of climate over the Earth’s surface--- latitudinal patterns of biome distribution Most terrestrial biomes are named for major physical or climatic features (predominant vegetation) The species composition of any biome differs from location to location. Human activity has radically altered the natural patterns of periodic physical disturbance. Humans have altered much of the Earth’s surface, replacing original biomes with urban or agricultural ones. 1.2 TROPICAL FOREST Tropical forest ○ Found close to the equator. ○ Located in the tropics (23.5 latitude of the equator). Average temperature is 23ºC with 12-hr daylight length. Three types of tropical forest exist – tropical dry forest, tropical deciduous forest, and tropical rainforest. ○ Tropical forests are stratified, and competition for light is intense. ○ Animal diversity is higher in tropical forests than in any other terrestrial biome. Tropical dry forest ○ Short dry period in a very wet tropical region ○ Precipitation is highly seasonal. Dry season in the forest is longer, and rainfall is less common. Succulents and thorny shrubs are the most common vegetation of this biome. 2  ○ Tropical deciduous forest – deciduous trees are common to this biome. During the long dry season, these trees shed their leaves to conserve water. Resprouting of leaves occurs when the rainy season starts. Tropical rainforest ○ Receive the constant greatest amount of rainfall (greater than 250 cm/yr) or (200-400 cm annually) of all the tropical forests. It is said to be one of the biomes with the greatest diversity. ○ The forest biome is characterized by high temperature and moist habitat. ○ Seasonality: wet and dry season (winter is absent). ○ The length of daylight is 12 hours Precipitation is evenly distributed throughout the year with annual rainfall exceeding 2000 mm. ○ Highest animal diversity. ○ Highest plant diversity. ○ Soil is nutrient-poor and acidic. ○ Decomposition of products is immediately taken up by the plant's extensive root system. ○ Sunlight is a limiting factor. ○ Canopy in tropical forests is multilayered and continuous, allowing little light penetration. Deserts ○ An ecosystem that forms due to the low level of rainfall it receives each year. ○ Deserts have low and highly variable rainfall, generally less than 30 cm per year. ○ Temperature varies greatly seasonally and daily. ○ Marked by the dry condition of soil and atmosphere as it receives the least amount of precipitation of all biomes. In areas where deserts are located, the descending dry air absorbs available moisture, thus leaving the biome dry. 3 ○ The plants that grow in this biome are those adapted to a low water condition, capable of storing much water. ○ Most animals living in deserts are nocturnal, to avoid the drastic effects of extreme temperature and water scarcity. ○ Fact: There are many deserts around the world going from extremely hot climates such as the Sahara to freezing climates. Not all deserts are hot and believe it or not Antarctica is a desert., all deserts are extremely hostile and some animals over millions of years have adapted to living in the dangerous environment. ○ How are deserts classified? Deserts are classified on how much rain-fall the area receives per year If it receives under 254 mm per year it is classified as a desert 2 types of desert: hot and cold. ○ COLD DESERT Average annual rainfall: