Annual plants leave behind seeds to germinate in spring.
Bear goes into a state of reduced metabolism.
Spider lays eggs in a fuzzy cocoon to hatch in spring.
Tree goes into dormancy, losing leaves.
Insects lay eggs or pupae.
Frog reduces its metabolism and produces antifreeze chemical.
nature’s design energy-saving methods reduce energy expenditure In winter, there is less energy input to the system due to less photosynthesis. Staying warm and searching for food during cold weather is costly. One strategy for coping with this challenge is to reduce the energy expended.
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Some animals reduce their metabolism during extremely cold periods. For example, bats, European hedgehogs, and some ground squirrels drastically reduce their metabolism during the winter, expending stored fat slowly. Breathing and heart rate slows and body temperatures are reduced. Trees and shrubs lose their leaves and become dormant.
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Frogs and insects use a combination of lowered metabolism and production of antifreeze chemicals to survive the winter. Antifreeze chemicals prevent formation of ice crystals, which can damage sensitive cell membranes. An extreme form of reducing metabolism is dying while concurrently leaving offspring behind in a protected state. While this is not beneficial for the individual, it ensures the continuation of the population and species. Examples include insects that leave their young in the form of eggs or pupae, annual plants that leave behind seeds, and spiders that leave eggs in fuzzy casings. Deep snow creates problems for deer, causing them to expend extra energy to move around and avoid predators. Deer spend winters in sheltered areas with lower snow depth.
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ENERGY RESPOND TO SEASONAL CHANGE • PLANTS AND ANIMALS I
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Winter is a time of reduced energy availability. Excessive energy expenditure is a challenge in winter. Seasonal adaptation of activity levels saves energy. Multiple strategies for coping with winter’s challenges increase survival.