On pgs 51-52, Carroll discusses the climate of Wyoming and how it has changed from a lush tropical climate to a semi-arid desert climate over the course of 40-50 million years. Let us discuss climates...
Name ONE climate, it's temperature ranges, amount of rainfall, where the climate is found on Earth today, as well as specific flora and fauna found in areas with such a climate.
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A desert is one of the many terrestrial biomes that exist on today's planet. Rainfall of less than 30 centimeters per year largely determines the area that will become a desert. Deserts have an annual mean temperature ranging from 7.3 degrees Celsius to 28.05 degrees Celsius (Campbell 1101). Deserts that are west of the Rocky Mountains and in central Asia are relatively cold. Cold Deserts accumulate some amount of variable snow during the winter time. The specific flora that inhabit such a biome include the giant saguaro cacti and deeply routed shrubs, "Hot and Dry Deserts vegetation is very rare. Plants are almost all ground-hugging shrubs and short woody trees. All of the leaves are replete (packed with nutrients). Some examples of these kinds of plant are Turpentine Bush, Prickly Pears, and Brittle Bush. For all of these plants to survive they have to have adaptations. Some of the adaptations in this case are the ability to store water for long periods of time and the ability to stand the hot weather," (http://www.blueplanetbiomes.org/desert.htm). Such plants are probably CAM and C4 plants. CAM and C4 plants evolved in hot, arid climates by tackling the problem of dehydration. C4 photosynthesis minimizes photorespiration and enhances sugar production through the C4 pathway. The C4 pathway introduces CO2 to PEP carboxylase which fixes CO2 and a four carbon compound (usually Malate) delivers the atoms of the CO2 into a bundle sheath cell via plasmodesmata. The Calvin cycle occurs and 3 pyruvate enter the mesophyll cell while sugar is delivered to vascular tissue (to review C4 plants and their pathways, refer to page 192 in Campbell). CAM plants open their stomata during the night and close them during the day; "Closing stomata during the day helps desert plants conserve water, but it also prevents CO2 from entering the leaves. During the night, when their stomata are open, these plants take up CO2 and incorporate it into a variety of organic acids," (Campbell 192). Such CAM/C4 plants that are found in the desert also include: Barrel Cactus, Brittle Bush, Mojave Aster, and the Soaptree Yucca (http://www.blueplanetbiomes.org/desert_plant_page.htm). For specific fauna that inhabit the biome: "Hot and Dry Deserts animals include small nocturnal (only active at night) carnivores. There are also insects, arachnids, reptiles, and birds. Some examples of these animals are Borrowers, Mourning Wheatears, and Horned Vipers. Cold Deserts have animals like Antelope, Ground Squirrels, Jack Rabbits, and Kangaroo Rats," (http://www.blueplanetbiomes.org/desert.htm). The climate today is found in Northern Africa (and parts of Sourthern Africa), parts of Asia, Central America, Southern South America, and Australia (Campbell 1114). From a thematic perspective, evolution and continuity/change are the two most important themes present here. Biomes are constantly shaped by evolution (the driving force being natural selection) and many different organisms are being mutated. Some thrive with favorable mutations while others die off. The continuous changing nature of biomes also correlates with Carroll's explanation of the climate of Wyoming becoming a semi-arid desert. There is always change. Whether that change be brought about by mutations, natural selection, and evolution individually or all three working together, there is one constant fact: there is change.
ReplyDeleteThe arctic tundra is a terrestrial biome often characterized by a lack of biodiversity due to harshly cold temperatures and frozen soil called permafrost. Arctic tundra is usually low in altitude but located very close to the Earth’s north pole, so the lack of direct sunlight causes extremely low temperatures. Temperatures in arctic tundra range from -50 degrees Celsius in the deep winter to 12 degrees Celsius on a sunny summer day. This wide range of temperatures exerts a large amount of selective pressure on organisms living in the tundra, making any mutation that causes an enzyme to become less efficient to be even more of a disadvantage than in a warm environment due to the low kinetic energy of the cold.
ReplyDeleteRainfall in the tundra is very similar to that of the desert. Annual rainfall averages between 18-25 cm, making survival for large vascular trees such as higher order angiosperms impossible when coupled with the root restraining properties of the permafrost. Permafrost is the frozen portion of tundra soil that is present from about 25-90 cm down in the ground. Accordingly, no trees are able to grow in the tundra. Also very interesting is the effect of the temperature swing on the permafrost. During the winter, the permafrost grows in size, which further limits plants’ abilities to survive. In the summer, the permafrost begins to thaw, creating streams and bogs that allow the plants, which are mostly bryophytes (which if you remember need water to facilitate their flagellated sperm), to reproduce.
The flora and fauna of the arctic tundra are not surprisingly scarce with very little biodiversity. Most of the flora consists of nonvascular plants, usually of the phylum bryophyta and hepatophyta, such as sedges, mosses and lichens. This is most likely due to the ability of these plants to occupy the topsoil of the tundra without being impeded by the deeper permafrost. There are surprisingly few vascular plants, most of which are various types of grasses, which are also small enough to be able to occupy a niche in the arctic tundra. The most common fauna in the arctic tundra are caribou, oxen, arctic foxes, snowy owls, lemmings, and rarely polar bears. These animals of the phylum chordata are characterized by heavy fur or insulation that lowers heat exchange with the environment. All of these animals are thermoregulators.
Deciduous Forest
ReplyDeletehttp://www.blueplanetbiomes.org/deciduous_forest.htm
Deciduous forests are located in the Eastern half of the United States, parts of Europe and Eastern Asia. Deciduous forests also appear on the southern tip of South America and parts of Australia and New Zealand. As one can see, most of these regions fall into mid-latitude ranges. In fact, almost every deciduous forest is located between 23o north and 38o south. Deciduous forests have four distinct seasons. The average temperature is 50 degrees and the average rainfall is anywhere from 30 to 60 inches per year. The average temperature and rainfall are also somewhat controlled by the mid-latitude locations of the deciduous forests. Some floras that appear in deciduous forests include American Beech, Carpet Moss, Guelder Rose, Lady Fern, Pecan, Shagbark Hickory, White Birch, and White Oak. Some common faunas that occur in such regions are eagles, bears, deer, chipmunks, squirrels, and coyotes. According to the diagram above, we all live in a deciduous forest biome. When looking at the above information and comparing that to our local conditions, it is clear that the diagram is correct. We have varying weather conditions and have seen most of the aforementioned flora and fauna located in our area.
I had a picture, but it did not work with blogger so here's the link:
ReplyDeletehttp://www.blueplanetbiomes.org/images/deciduous_location_map001.gif
The tropical climate is represented in the tropical forest biome, known for its great biodiversity. This biome exists in areas located north of the tropic of Capricorn (23.4 degrees south latitude) and south of the tropic of Cancer (23.4 degrees north latitude). Specifically, tropical forests are located in the Caribbean islands, South America's Amazon basin, equatorial African coasts, Madagascar, India, Indochina, Indonesia, and northern Australia. Since the tropical forest biome is limited to equatorial latitudes, the biome experiences a consistent amount of sun light and day length (12 hours). The consistent day length maintains warm temperatures in tropical forests ranging from 22 – 34 degrees C. This constant warm temperatures and solar energy speeds up the water cycle and thus causes heavy rain fall. Tropical forest experience 175 to 1092 cm of rain yearly. However, some tropical forests experience much rainfall throughout the year while others, tropical dry forests, experience monsoons followed by drought.
ReplyDeleteThe extensive rainfall, constant day length, and warm temperatures of the tropical forests allow the biome to host a wide variety of flora and fauna. The type fauna varies primarily with the frequency of rainfall throughout the year. The topical dry forests are home to resilient shrubs, deciduous canopy trees like Planchonella grayana (italics), and succulents like cacti which can survive harsh droughts. Tropical wet forests which receive heavy rainfall through out the year house a wide variety of deciduous trees, herbaceous plants and shrubs. Tropical wet forests experience vertical stratification where a canopy is formed by the leaves of tall woody flora, shrubs and vines populate an under-story, and the forest floor is littered with leaves and herbaceous plants. The tropical wet forests host a diverse variety of fauna consisting largely of smaller organisms; the dense flora limits space and applies natural selection pressure against large size. Amphibians (due to the heavy rainfall and warm temperatures), fungi (due to the large amount of plant detritus), and insects (due to the warm temperatures and abundant food in the form of flora and fauna) are more common in tropical wet forests than most other biomes. Tropical dry forests fauna consist of larger organisms than tropical wet due to the less dense flora. Grazers like dear and elephants are common in tropical dry forests. Large predators like the tiger and the Komodo dragon can also occupy tropical dry forests due to the greater living space and larger prey these forest have. The constant high temperatures in the tropical forest biome in general allow many thermo-conformers to survive and reproduce in this biome.
http://www.blueplanetbiomes.org/savanna.htm
ReplyDeleteThe savanna is a grassland with very few shrubs and trees. Savannas are typically found amidst tropical rainforests and deserts. The climate is composed of two seasons- a long dry winter and long wet summer. Despite the time of year, the temperature is relatively warm (between 68 and 86 degrees F). In the winters, the temperatuere is between 68 and 78 degrees F while in the summer, the temperature falls between 78 and 86 degrees F. There is typically between 10 and 30 inches of rainfall per year, most of the rainfall being in the summer. There is a lack of or very little rainfall between the months of December and February.
The most well known savannas are located in Africa, especially the East African savannas (think Lion King setting). Savannas are also located in South America in Brazil, Colombia, and Venezuela. There is also a large savanna in northern Australia where kangaroos are found.
Moving onto animals of the savanna...
African elephants (savanna elephants - Loxodonta africana (italicized)) are the largest land mammals in the entire world. As herbivores, african elephants eat grasses, fruits, tree leaves, bark, shrubs, and vines. African elephants apparently have excellent memories, for according to Science Daily, older female elephants remembered where food and water was available during periods of extended drought in the savannas. (http://www.sciencedaily.com/releases/2008/08/080811200337.htm)
I'll do one more example of an animal...
Koala bears (Phascolarctos cinereus- italicized) are small marsupials (only 33 inches long!) that are always found on trees. Koala bears are able to hang on to trees while also supporting their weight by having rough paws that provide traction. The fur of a koala keeps the body both cool and warm. The fur of a koala also turns away moisture so the bear can stay plenty warm during periods of heavy rainfall (summer afternoons). Koala fur is also perfect for hiding from predators. Koalas are normally found in the savannas of Australia, not Africa. Koalas eat eucalyptus leaves, which are normally poisonous but the koala has developed an immunity to the poison. According to a Science Daily report, the increase in carbon dioxide in the air due to rising temperatures has promoted the development of more "anti-nutrients" (mess up digestion or simply are more toxins) in eucalyptus leaves, the koala bear's main source of food. This problem will most likely cause a decrease in the population of koala bears :( (http://www.sciencedaily.com/releases/2008/05/080508131118.htm)
Moving onto plants...
The Umbrella Thorn Acacia (Acacia tortillis- italicized) is the tree you probably think of when someone says "African savanna". Acacia's can withstand extremely high day temperatures and extremly low night temperatures. Acacia's have a very long taproot (pg. 722 of Campbell). Therefore, during the long and dry winter season, acacias can obtain water from deep in the Earth. From the taproot extends an immense system of root branches. This system extends farther than the "crown" of the acacia. To even more increase the surface area of roots, there are root hairs also on the roots to obtain even more water during the dry season. Umbrella Thorns, from the name, also have thorns to stop animals from eating the leaves and flowers. The Umbrella Thorn also has little leaves so that not too much water is lost from the tree. The "umbrella" top of the acacia allows immense amounts of sunlight to be absorbed. The acacia and other savanna plants most likely have lots of xylem tissue for water transport.
Besides having the best name, the Chaparral biome is a very diverse biome. It is located in midlatitude coastal areas with mild, rainy winters and long, hot dry summers. The Chaparral lies in a belt of prevailing westerly winds, and can be found from 30 to 50 degrees North and from 30 to 40 degrees South (latitude). It surrounds the Mediterranean Sea, as well as western California, the tip of South Africa, the southwestern tip of Australia, and a small part of Chile. The temperature range for the Chaparral biome is 30 to 100 degrees Fahrenheit. The Chaparral biome receives approximately 15 to 39 inches per year. Most of this comes in the winter, leaving the summer months very dry. Because the summer includes a long period of dryness and heat, periodic fires are very common, and are in fact an essential part of this biome. Many plant species have adapted to the periodic fires. For example, some Chaparral shrubs produce seeds that will only germinate after a fire. In addition, some plants store large amounts of food in their fire-resistant roots, so that they can resprout quickly. While many of the fires are naturally caused, careless human activity can also play a large role in creating fires. The devastating fires of California and Australia are examples of how the periodic fires can sometimes get out of control, and can be harmful. A very common plant species is the scrub oak (Quercus berberidifolia - (italics)). In fact, this species is so common that the word chaparral comes from the Spanish word for the scrub oak, chaparro. Other flora of the Chaparral region include the Chaparral pea (Pickeringia montana), the California buckwheat (Eriogonum fasciculatum), and the Lemonade berry (Rhus integrifolia), as well as many others. Fauna of this region include a very wide variety of bird species, such as the California thrasher (Toxostoma redivivum), Western scrub jay (Aphelocoma californica), Greater roadrunner (Geococcyx californianus), and Wrentit (Chamaea fasciata).
ReplyDeleteNote: all species names should be italicized, but I can't figure out how to italicize them on the blog.
The temperate grassland has about 25-30inches of rain on average. They are very similar to savannas because of the open grassland with few trees or scrubs. However, temperate grasslands are typically colder in climate and have less precipitation. Winters can reach as low as -40ºF and the summer can reach as high as 70ºF. The temperate grasslands are located in the pampas of Argentina, downs of Australia, plains and prairies of Central North America, puszta of Hungary, downs of New Zealand, steppes of Russia, and veldts of South America. Fauna typically found in the grasslands are bison, gazelles, zebras, rhinoceroses, deer, coyotes, and foxes. The flora includes buffalo grass, sagebrush, perennial grasses, and sunflowers. The lack of trees and other taller vegetation is due to the seasonal drought, occasional forest, and larger foraging animals. Typically, the soil in these areas are very fertile and good for agricultural uses.
ReplyDeleteMany of these different climates are found on the various different continents. However, the same organisms are not found on all of the same biomes on the different continents. An example is the kangaroos found in Australia. Australia is made up of tropical forest, savanna, temperate grassland, dessert, and chaparral (Campbell 1112). The kangaroos are found in Australia in the savanna, temperate grassland, and desert biomes (Campbell 1093). However, kangaroos are not found in these same biomes on the other continents. Why is this? If kangaroos were to be introduced to the same biomes on different continents would they be able to survive and reproduce?
The coniferous forest is a biome that consists largely of cone-bearing trees. Coniferous forests appear between the deciduous forests to the south as explained by David Bruk and the arctic tundra to the north as explained by Aaron Goone. The coniferous forest lies in between 50-60° N latitude in North America and Asia. Coniferous Forests can be found Canada, Washington, and Russia. The “northern coniferous forest, or taiga, is the largest terrestrial biome on Earth” (Campbell 1116).
ReplyDeleteThe coniferous forests are also called boreal forests. The temperature ranges from -40 to 20°C. Because the coniferous forests are near the northern areas of the earth, the amount of sunlight received is not in great amounts and is not intense. Because of the low levels of sunlight, the forests remain cold throughout the year, their average summer temperature a chilly 10°C. The precipitation averages 20 inches per year. Because much of the precipitation is due to the heavy snowfall, the water is not easily accessible to the plants, making the coniferous forest a relatively dry environment.
Much of the climate of the coniferous forests is cold during the year, so the adaptations of the flora and fauna adapt to counter the cold. Because the coniferous forests are composed mainly of tree species bearing needles instead of broad, flat leaves and cones instead of flowers, there is not much diversity of the tree species. The dominant tree species include the black spruce and white spruce. Both of these trees are evergreens, meaning that they maintain leaves (their needles) during the whole year instead of shedding their leaves like some deciduous trees. The adaptation of having needles instead leaves conserves water in the relatively dry environment of the coniferous forest. As we have learned, water escapes the leaf from the leaf’s stomata. If the leaf has a large surface area, more water will be lost. Because the needles of the coniferous trees have a waxy covering as well as a small surface area, less water is lost, promoting water conservation. The needles of evergreens relate to the theme of structure/function, a theme which dictates that “form and function are correlated at all leves of biological organization” (Campbell 22). Because the form, or the size, of the leaf is reduced, a function of the leaf is that water conservation is improved. Another adaptation of the coniferous forest would be its conical shape. The conical shape “prevents too much snow from accumulating on and breaking their branches” (Campbell 1116). Other species of plants in the coniferous forests include jack pine, red spruce and firs.
The fauna of the coniferous forest biome have to adapt to the cold temperatures as well. The coniferous forest shares some of the same animals species like the arctic fox, arctic hare, caribou, and snowy owls as the tundra mentioned by Aaron Goone. Other animals of the coniferous forests include the bobcat, which adapts to the changing seasons by changing its coat. For example, during fall, the coat of the bobcat is brown, allowing the bobcat to blend in with the dark foliage, and the bobcat’s coat changes to white during the winter so the cat can be hidden in the snow. This adaptation relates to the theme of interaction with the environment, which deals with the exchanges of organisms with their surroundings. Because the surroundings of the bobcat change during the year, the bobcat also changes its coat to adapt to its surroundings. Animals such as the brown bear adapt to the cold winters by engaging in hibernation, an example of torpor. Birds like the palm warbler and the black-backed woodpecker adapt to the long winters by migrating to warmer areas.
http://www.fws.gov/northeast/lakeumbagog/boreal%20birds.htm
http://www.enchantedlearning.com/biomes/taiga/taiga.shtml
http://www.fw.vt.edu/dendro/Forsite/ncfbiome.htm
http://earthobservatory.nasa.gov/Experiments/Biome/bioconiferous.php