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Maintaining Stability in Unstable Conditions

Topic: Homeostasis
by Bridget, 2020 Cohort

What is homeostasis?#

Homeostasis in simple terms is a state of stability. The term is usually used in reference to the internal stability of biological organisms but can be used to understand stability within any system. Various stimuli can have impacts on systems. Some systems can correct for those impacts and maintain stability (homeostasis).

How is homeostasis maintained?#

Homeostasis is maintained by negative feedback loops (pictured). When a stimulus creates an imbalance within a system there are three steps involved in correcting it:

• The imbalance is sensed by a receptor.
• The receptor sends the information to a control centre to be processed and recognised. * The control centre triggers a response (known as the effector) to restore balance.

Example: Regulation of human body temperature#

Human body temperature is a perfect example how homeostasis is maintained with the use of a negative feedback loop.

The human body needs to maintain a temperature of approximately 37^oC in order to function correctly. If this temperature changes too much it can lead to serious health concerns or even death. People live in environments with fluctuating external temperatures, and actions (such as exercise) can also impact body temperature. It is therefore vital that there are measures in place to maintain stable body temperature in unstable conditions.

When there is a change in body temperature it is sensed by the nervous system (the receptor). The information is then sent to the brain (the control centre) for processing. There are several responses (effectors) to temperature change, dependent on whether the person is too hot or too cold. To an observer, a visually obvious response to excessive heat is sweating, which lowers body temperature through evaporative cooling. When a person is too cold, the most obvious response is shivering, which creates heat through energy expenditure.

Despite these stabilising responses, a stimulus that is too great will still result in the loss of homeostasis and the subsequent negative impacts on the human body.

Example: Regulation of global temperature#

The Earth’s ability to support life relies on various homeostatic tendencies, including the maintenance of a global temperature which supports large amounts of liquid water.

The temperature on Earth has been in a state of dynamic stability and warmth for the last ~11,650 years (the Holocene epoch). During this time there has been substantial population growth for humanity.

Almost all scientists agree that our climate is changing, more specifically becoming warmer. It is also generally agreed upon that humanity is a large contributor to climate change due to our emissions of greenhouse gasses (mostly CO₂ and methane). Climate change threatens several ecosystems and subsequently the species that rely on those ecosystems. Droughts and heatwaves have both occurred more frequently since the 1950s. These changes threaten planetary biodiversity and are evidence that our current way of life is unsustainable.

The actions of humanity are threatening planetary homeostasis regarding temperature. This can be a scary thought but can also be hopeful. If we understand the factors that threaten homeostasis, then we are better equipped to protect that homeostasis.

Explore this topic further#

• The Emergence of Environmental Homeostasis in Complex Ecosystems{.link-ext target=”_blank”}
• Homeostatic Control{.link-ext target=”_blank”}

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Disclaimer#

This content has been contributed by a student as part of a learning activity.
If there are inaccuracies, or opportunities for significant improvement on this topic, feedback is welcome on how to improve the resource.
You can improve articles on this topic as a student in "Unravelling Complexity", or by including the amendments in an email to: Chris.Browne@anu.edu.au

What is homeostasis?#

Homeostasis in simple terms is a state of stability. The term is usually used in reference to the internal stability of biological organisms but can be used to understand stability within any system. Various stimuli can have impacts on systems. Some systems can correct for those impacts and maintain stability (homeostasis).

How is homeostasis maintained?#

Homeostasis is maintained by negative feedback loops (pictured). When a stimulus creates an imbalance within a system there are three steps involved in correcting it:

• The imbalance is sensed by a receptor.
• The receptor sends the information to a control centre to be processed and recognised. * The control centre triggers a response (known as the effector) to restore balance.

Example: Regulation of human body temperature#

Human body temperature is a perfect example how homeostasis is maintained with the use of a negative feedback loop.

The human body needs to maintain a temperature of approximately 37^oC in order to function correctly. If this temperature changes too much it can lead to serious health concerns or even death. People live in environments with fluctuating external temperatures, and actions (such as exercise) can also impact body temperature. It is therefore vital that there are measures in place to maintain stable body temperature in unstable conditions.

When there is a change in body temperature it is sensed by the nervous system (the receptor). The information is then sent to the brain (the control centre) for processing. There are several responses (effectors) to temperature change, dependent on whether the person is too hot or too cold. To an observer, a visually obvious response to excessive heat is sweating, which lowers body temperature through evaporative cooling. When a person is too cold, the most obvious response is shivering, which creates heat through energy expenditure.

Despite these stabilising responses, a stimulus that is too great will still result in the loss of homeostasis and the subsequent negative impacts on the human body.

Example: Regulation of global temperature#

The Earth’s ability to support life relies on various homeostatic tendencies, including the maintenance of a global temperature which supports large amounts of liquid water.

The temperature on Earth has been in a state of dynamic stability and warmth for the last ~11,650 years (the Holocene epoch). During this time there has been substantial population growth for humanity.

Almost all scientists agree that our climate is changing, more specifically becoming warmer. It is also generally agreed upon that humanity is a large contributor to climate change due to our emissions of greenhouse gasses (mostly CO₂ and methane). Climate change threatens several ecosystems and subsequently the species that rely on those ecosystems. Droughts and heatwaves have both occurred more frequently since the 1950s. These changes threaten planetary biodiversity and are evidence that our current way of life is unsustainable.

The actions of humanity are threatening planetary homeostasis regarding temperature. This can be a scary thought but can also be hopeful. If we understand the factors that threaten homeostasis, then we are better equipped to protect that homeostasis.