Weather Short-Term Temperature & Precipitation
Weather Objectives
- Describe the basic components of weather, including clouds.
- Provide examples of organism responses to changing weather, including the significance of temperature control.
- List the characteristics of mammalian species, including rodents.
If you have camped, you have probably had the experience of waking up in the morning realizing that the weather forecast was off and it rained in the night. Everything is soaked, there may even be water standing in the tent. That slight change of weather is rough on us, the impact on other organisms can be even more significant.
From earlier in the course, both weather and climate are based on temperature and precipitation data. Which one is short-term?
Solar energy drives the water cycle of evaporation and precipitation, so there is continual rain at the equator and minimal precipitation at the polar regions.
What can be startling is how little of the Earth’s total water is in the atmosphere. Study the figure below. Where is most of Earth’s water located? Of the freshwater, most is frozen, and the next largest quantity is in the _____. Less than a percent makes up the lakes and streams discussed in Guide 7B, and less than 0.1% is in the atmosphere. But clearly that small percentage is critical.
Condensation in clouds results in precipitation that fills streams, waters plants, and provides drinking water for animals.
If you are interested in “Cloud Collecting,” there is more on this guide’s resources page.
Water vapor also reduces sunlight intensity, modulating temperature extremes.
Here in the Willamette Valley where it often rains throughout the late fall, winter, and early spring, clear and cold nights can lead to “hard frosts” that damage plants. Atmospheric moisture reduces the likelihood of these frosts.
Some species, including terrestrial isopods, rely on moist air for survival. Watch what happens when I add moisture to this enclosure.
Temperature Regulation
Even with layers of clothing, heating, and air conditioning, we think about our temperature many times every day. Other species are also continually maintaining temperature.
We had a frosty morning, perfect for introducing thermoregulation in animals.
Maintaining balance in the body is called homeostasis.
Similar to the idea of a thermostat, there is a set point or range, and there can be fluctuations around that point, but the mechanisms of the body typically try to keep fluctuations to a minimum.
Birds and mammals maintain a relatively constant internal body temperature. This form of homeostasis is called homeothermy, also known as “warm-blooded.” It takes continual burning of energy-containing molecules to maintain temperature, so even though birds and mammals can be active in the cold, they have to eat a lot of food to maintain temperature. This production of heat from within the body is called endothermy.
Most other animals, including reptiles, get much of their heat from their environment, a process called ectothermy. Ectotherms move from shade to sun, or underwater to basking on a rock to alter body temperature.
Ecto = outer
Endo = inner
Body structures can assist with heating or cooling.
Elephant Ears
Thick Fur
Mammals
Mammals are the most studied of all animals, not only because we are mammals, but also because of their role in our food supply and as our companion animals.
This video provides an overview of mammalian characteristics.
Rodents are found in ground burrows, in trees, and some species like the beaver are semi-aquatic. Sizes range from small mice to the large capybara.
Rodents have continually growing incisor teeth that they use to gnaw food, dig tunnels, and defend themselves.
Most rodent species are small with short limbs and a long tail.
Wear a mask if there is a possibility of fecal materials that could be pulverized and become airborne. This is particularly a concern in regions with Hantavirus.
The largest rodent is the capybara of South America, they can weigh up to 140 pounds.
They are relatives of significantly smaller guinea pigs.
Although some rodents like the capybara and guinea pig eat leaves (grass blades) and beavers eat plant stems, most rodents eat seeds.
Squirrels and many other species stash seeds in reserve, sometimes utilizing smell and memory to retrieve cached food months later.
This is a space under a bird feeder at the High Desert Museum, near Bend Oregon.
How many species do you see?
It could be tempting to say the largest rodent was the parent of the smaller individuals, but these are two different species. The larger organism is a ground squirrel, the smaller individuals with stripes along the sides of their heads are chipmunks. These species both eat seeds and have similar burrows, resulting in frequent interspecific competition.
This is a ground bird feeder on the South Oregon Coast.
How many species do you see?
There is a squirrel, chipmunk, and rats. These rats are different than the Rattus norvegicus used as pets and lab animals, this is Rattus rattus. Rats have a different body shape, tail, and markings than the squirrels and chipmunks. They also eat a more omnivorous diet.
The next section explores the cause and effects of seasonal change.
Check your knowledge. Can you:
- describe the basic components of weather, including clouds?
- provide examples of organism responses to changing weather, including the significance of temperature control?
- list the characteristics of mammalian species, including rodents?
Go back to the Daily Rhythms Page
Go forward to the Seasons Page
Short-Term Lecture Guide Contents
Complete all four of these sections before taking the quiz and making your media piece.
Back to Module 6
Conditions
This Guide
Short-Term
