Pre-Reading
Pre-Reading Activity
Look at the definition below. Then, discuss the questions below.
biome: ecological community of plants, animals, and other organisms that is adapted to a characteristic set of environmental condition
- The definition uses many complex words. In simple terms, what is a biome?
- This reading is about terrestrial (land) biomes. There are eight major types of terrestrial biomes. Do you know what they are?
- Quickly preview the text, to check your answers to question 2. How many terrestrial biomes did you correctly identify?
- What type of biome do you live in? What type of vegetation does it have? How much precipitation does it get?
Reading 3: Terrestrial Biomes [1]
The Earth’s biomes are categorized into two major groups: terrestrial and aquatic. Terrestrial biomes are based on land, while aquatic biomes include both ocean and freshwater biomes. The eight major terrestrial biomes on Earth are each distinguished by characteristic temperatures and amount of precipitation. Comparing the annual totals of precipitation and fluctuations in precipitation from one biome to another provides clues as to the importance of abiotic factors in the distribution of biomes. Temperature variation on a daily and seasonal basis is also important for predicting the geographic distribution of the biome and the vegetation type in the biome. The distribution of these biomes shows that the same biome can occur in geographically distinct areas with similar climates (Figure 6).
Tropical Wet Forest
Tropical wet forests are also referred to as tropical rainforests. This biome is found in equatorial regions near the earth’s equator (Figure 6). The vegetation is characterized by plants with broad leaves that fall off throughout the year. Unlike the trees of deciduous forests, the trees in this biome do not have a seasonal loss of leaves associated with variations in temperature and sunlight; these forests are “evergreen” year-round.
The temperature and sunlight profiles of tropical wet forests are very stable in comparison to that of other terrestrial biomes, with the temperatures ranging from 20 °C to 34 °C (68 °F to 93 °F). When one compares the annual temperature variation of tropical wet forests with that of other forest biomes, the lack of seasonal temperature variation in the tropical wet forest becomes apparent. This lack of seasonality leads to year-round plant growth, rather than the seasonal (spring, summer, and fall) growth seen in other biomes. In contrast to other ecosystems, tropical ecosystems do not have long days and short days during the yearly cycle. Instead, a constant daily amount of sunlight (11–12 hours per day) provides more solar radiation, thereby, a longer period of time for plant growth.
The annual rainfall in tropical wet forests ranges from 125 to 660 cm (50–200 in) with some monthly variation. While sunlight and temperature remain fairly consistent, annual rainfall often changes. Tropical wet forests have wet months