w9 Temperature and Moisture Flashcards
what are the 4 primary factors that limit species ranges?
- physical and chemical factors (we focus on temperature and moisture… and salt)
- dispersal
- habitat selection
- other species
having temperature and moisture as limiting factors of geographic distributions, what should organisms do during these conditions? (2)
must tolerate or avoid
how might temperature or moisture limit a distribution? (2)
- by affecting survival…
- by affecting reproduction…
…direct effects (overheating, freezing, etc) ….indirect effects (By affecting interactions with other species [e.g., Species A is a weaker competitor than Species B, but only under cool conditions])
evolutionary adaptations that help with tolerance are ___. + toucan bills example
pervasive (spread throughout so thoroughly as to be seen or felt everywhere)
Toucan bills are used in thermoregulation, where blood is shunted to the bill while flying (cooling off) and restricted to the bill when at rest (conserving heat). But did large bills evolve in Toucans for thermoreg? That bit is unclear…
topic: global patterns of temp and precipitation
Many species are limited by temperature, moisture, and nutrients. These are somewhat predictably distributed across the earth’s surface.
1. explain how temperature patterns are created by the relation of the sun and earth
2. and how that global temperature pattern affects precipitation by the atmospheric circulation then comparing where the rainforests and deserts are commonly located within the equator region
3. explain what the other atmospheric cells are and how they interlock like a gear train
slides
T or F: temperature and precipitation predict primary productivity
true; combining them allows us to see patterns of PP (vegetation on the global scale)
the vegetation of any site is usually considered a product of the area’s _____. this implies that ____ factors, ____ and ____ primarily are the main factors controlling the distribution of vegetation.
The vegetation of any site is usually considered a product of the area’s climate. This implies that climatic factors, temperature and moisture primarily, are the
main factors controlling the distribution of vegetation
why are plants bigger in warm, moist areas?
due to water retention in plants where precipitation is playing a big role.
water is primarily important to plants due to growth and photosynthesis. A major challenge for plants living in an atmospheric environment is to develop a barrier against uncontrolled water loss. The barrier has to be efficient, translucent for photosynthetically active radiation, flexible, and self‐healing. The plant cuticle combines all these properties in an economic way
how do plants lose water? how is water movement being controlled during the process of transpiration?
a process called transpiration.
when leaves open their stomata pores to absorb CO2 to make sugar, water is lost to the atmosphere at a prolific rate relative to the small amount of CO2 absorbed. so the amount of water lost via transpiration can be high. Along with the lost of H2O, O2 is also being released.
Water movement is controlled by the [ ] gradient of water vapor. So transpiration occurs when water moves due to having more water vapor inside leaves (where the air space is saturated with water vapors) than outside (where the air is unsaturated). This makes the air around leaves thirsty for water vapor, so water evaporates from the leaves. As water evaporates, it takes heat from the leaves to turn into vapor.
The balance between transpiration and photosynthesis forms an essential compromise; what is this costly balance?
stomata must remain open to build sugars but risk dehydration in the process.
Cuticular transpiration
Cuticular transpiration is the loss of water from the surface of the plant. This type of transpiration takes place when cuticle is very thin and there is no water scarcity. It accounts for only 2-5% of water loss. The waxy cuticle that covers the leaf surface is a very effective barrier to water movement.
what is an example of fluid retention in a plant? + expand how they are successful in surviving in their given environment
hint: cacti
Xerophytes like cacti use CAM photosynthesis, absorbing sunlight during the day while keeping stomata closed to conserve water. Their thick, waxy cuticles and spines minimize water loss and break up drying winds. Some, like Ephedra and cacti, primarily conduct photosynthesis in their stems. Their roots vary, with some having shallow, widespread roots to capture rainwater and others having deep taproots for underground water access. Cacti store water in their stems, enabling them to endure long periods of drought, such as the saguaro, which can absorb thousands of liters of water after a storm to survive up to two years without rainfall.
what is another strategy to survive in the desert? explain what is it and why it’s a strategy (it’s purpose)
seed banks. a place where suitable conditions are maintained to conserve seed specimens of different plant species (wild or cultivated). The objective is clear: to ensure the preservation of as many plants as possible for posterity
other words: a place where seeds are stored to preserve genetic diversity for the future.
SLIDE— CLARIFICATION
in cold deserts how does the cold or freezing temperatures limit many plant distributions and limit plant stature? explain
what happens extreme temperatures limit plant distributions?
freezing of water in the soil. The frozen water within the soil particle pores prevents the root of the plant to take up the water and on top of that, the leaves continute to lose water by transpiration. Thereby most of the water is not available to plants as it remains frozen for all or most of the years causing the plants to die cause it’s sucking up air causing elements to collapse. But there are 2 species of flowering plants that are found in antartica.
is moisture a less or more important factor that limits geographic ranges in animals than plants. why? + example
water is a major limiting factor in animals but not as much as plants, thereby less because animals can move away from dry conditions and seek water over relatively broad areas, plants cannot. Animals are mobile.
Animals do ultimately depend on plants for food (even top predators), and so their distributions are limited more indirectly by moisture by virtue of vegetation
- so when animals are limited by distribution of water it is actually due to the food source (vegetation that depends on moisture/water) rather than a direct effect of water on the animal itself like it is for plants (freezing water in soil for ex)
EXAMPLE:
The distribution of the Red Kangaroo in Australia coincides almost exactly with the 400mm annual rainfall line, and this is because they are dependent on the arid-zone grasses that thrive under this precipitation regime
