Structural And Physiological Adaptations
Structural Animal Adaptations
Use Of Surface Area : Volume Ratio In Mammals
For animals living in a hot dry environment like the chaparral biome homeostasis can be exceptionally difficult due to the conditions. Although there are a number of ways in which animals inhabiting a region like the chaparral biome can respond to temperature rises one of the most common is the use of the surface area to volume ratio by mammals. Mammals manage their internal temperature with large areas of exposed skin with little internal volume such as tails, legs or ears. These areas have a large surface area through which heat can escape and low volume which allows heat to more effectively pass through. For example, the black tailed jackrabbit has extremely large ears, which can reach a third of its body in length. The jackrabbit's large ears hold dozens of small blood vessels which expand when the animal is hot, allowing more quantities of blood to flow through the ears and be exposed to the external environment, cooling the blood as it moves. When the jackrabbit is cool the blood vessels constrict, lessening the amount of blood that passes through the ears. With the use of this adaptation the jackrabbit can very efficiently maintain its internal body temperature. This adaptation can also be found in a number of other desert mammals, such as foxes, rabbits, mice and rodents.
Fur And Feathers Of Desert Creatures
The varying conditions within the chaparral biome (hot during the day and cool to cold at night) require a covering layer which does not overheat animals and can efficiently evaporate sweat whilst also providing some warmth during the cold nights. Mammals living in this kind of environment typically have short, compact coats which ventilate well and allow sweat to evaporate quickly, cooling the animals much faster. Birds also have similar adaptations, with many having the ability to fluff or flatten their feathers, allowing them to regulate their heat exchange. One such example of an animal with a specialised coat is the ostrich, which has no feathers on its head, neck and legs but a fluffy coat of feathers on its back and abdomen. The lack of feathers allows heat to more efficiently escape and the thick coat of feathers protects the ostrich's back from the sun
Structural Plant Adaptations
Small Waxy Leaves And Hard Bark
In the chaparral biome where little to no rainfall occurs during the summer months it is necessary for plants to maintain their water levels and minimise water loss, this is done in a number of ways. Water loss is reduced mostly through structural adaptations such as small waxy leaves with a thick cuticle, the reduced size allows for less sun exposure and the waxy layer over a thick cuticle ensures little water escapes through transpiration. Leaves of these plants typically possess few stomata which helps further reduce the amount of moisture lost by the plant. The plants will also often have a trunk covered in hard rough bark, which protects the tree and minimises its water loss. Examples of plants in the chaparral biome with these structural adaptation include: manzanita, coyote brush and sage brush.
Specialised Root Systems
While plants in wetter environments may only be able to survive a few days without water plants in environments like the chaparral biome are capable of surviving months without moisture thanks to their specialised root system. The plants' roots systems tend to extend far beyond their canopy and occupy a large amount of space. These roots are typically close to the surface where they can absorb the largest amount of possible water from rainfall. The root systems generally don't go deeper than three feet as this is the maximum depth rainwater will reach. These plants also have deep tap roots which extend further below ground allowing them to reach deeper supplies of water. While plants in the chaparral biome may look spaced out and separated the ground between them is usually full of roots.
Physiological Animal Adaptations
Concentrated Urine In Mammals
Another way mammals are able to maintain their internal water levels by excreting more concentrated urine. When blood passes through the kidneys excess fluid is removed and exits the body along with other waste as urine. The amount of fluid removed from the blood is determined by how much water the animal has consumed, the less water consumed the more concentrated and vice versa. Animals in the chaparral biome naturally have very concentrated urine which mean little to no water is wasted and the liquids can be reabsorbed back into the body of the animal. This adaptation is demonstrated by most mammals in the chaparral biome where water retainment is crucial for survival.
Low Metabolism
In the chaparral biome, where food can be hard to come by, it is necessary for animals to conserve energy. One of the ways that animals can conserve energy is through low metabolic rates, meaning less sustenance is required for the organism to maintain itself. These animals automatically slow the chemical reactions in their bodies when food is in low supply. Some birds and small mammals have the ability to lower their metabolism, meaning they require less energy input but at the cost of less energy output.
Physiological Plant Adaptations
Crassulacean Acid Metabolism (CAM)
Crassulacean acid metabolism is a form of photosynthesis where water loss is reduced by keeping the stomata closed during the day, reducing transpiration through the stomata. The stomata open at night to absorb carbon dioxide, which is stored in vacuoles during the night and converted to energy by photosynthesis during the day. This method also increases the efficiency of the photosynthesis reaction. CAM is used by plants in arid environments where photosynthesis during the day would result in far too much water loss making survival difficult.
Ephemeral Life Cycles
Plants in the chaparral biome often rely on water to initiate their breeding cycle. The seeds of certain species can often wait months between rainfalls, until a suitable level of moisture is present. Due to the unreliable nature of rain in the environment plants have ephemeral (short) life cycles. Many species can complete their lifecycle in just a few weeks, utilising the available water. During dry periods many plants will become dormant and seeds will not sprout. When rainfall occurs the plants will sprout again and seeds will start to grow, in this way a seemingly arid landscape can be transformed in a few days as hundreds of dormant plants return to life. This period of life is short lived however, as water levels return to normal and the plants complete their life cycles. This ability to rapidly grow and reproduce allows plants to survive when others may die while in the process of growth.