Transcript Homeostasis and the envrionment

HOMEOSTASIS AND
THE ENVIRONMENT
AP Biology
Homeostasis and the Environment
• So far, we have looked at how homeostasis controls and
regulates our bodies (removal of nitrogenous waste,
immune system).
• While these are good examples of homeostasis, they are
at an organism or cellular level.
• We can also see examples of homeostasis at higher
levels such as populations, communities and ecosystems.
• The purpose of this exercise to to explore some of these
higher levels of homeostasis and the environment.
Assignment
• You will be given an example of homeostasis and the
environment.
• First, your group should figure out the following
• What level (biome
population
individual)?
• Does your example involve natural homeostasis, or response to a
disruptor?
• If it is in response to a disruptor, what is the disruptor?
• Gather any other relevant facts (use books, phones)
• Then you will answer the following short free response
question:
How does your example show
homeostasis and the environment?
Response
How does your example show
homeostasis and the environment?
• Remember, you only want to answer the question with
relevant information.
• Your response should be 4 or 5 sentences.
• The structure of the response:
• Define your example (give an example if applicable)
• Explain if it is natural or a disruption
• Explain how is shows homeostasis.
Example: Succession
Succession is the natural evolution or progression of an
ecosystem, and there are two types: primary or secondary.
Primary succession is a natural process where life
colonizes new land. Secondary succession can either be a
natural progression (a lake becoming a meadow then a
forest) or a response to a disruption (after a forest fire).
Succession shows how an ecosystem stabilizes after a
disruption as plants and animals return.
Examples
Station
1
Example
Station
Example
Predator/Prey
Relationship
5
Global Warming
Carrying
Capacity
6
Deforestation
3
Invasive
Species
7
Photoperiodism
4
Acid Rain
8
Biofilms (Quorum
sensing in bacteria)
2
Record the paragraphs below in your
table.
Example
Explanation
Predator/
Prey
Predator and prey relationships consist of a carnivore kill
and eating another animal. An example is when a pride
of lions stalks and kills a gazelle. The predator/prey
relationship involves homeostasis by regulating each
others’ population size.
Carrying
Capacity
Carrying Capacity is the maximum number of individuals
an environment can support based on the amount of
available resources. Limiting factors such as disease,
crowding and predators are natural regulators. The
limiting factors stabilize the population size and maintain
homeostasis.
Ecology and Homeostasis
Invasive
Species
An invasive species is an organism that is not native to a
specific location (introduced and spreads out of control). It
disrupts homeostasis in an ecosystem. For example,
rabbits were introduced to Australia and ate native plants
and over-populates because there are no natural
predators. It disrupts homeostasis because invasive
species unbalances the food web.
Acid
Rain
Acid rain is a human-caused environment effect caused by
chemical pollution that reduces the pH level of
precipitation. Acid rain is a disruptor by affecting
reproduction of plants and animals. It turns lakes acidic
(kills aquatic organism) and destroys nutrients needed by
plants. Homeostasis is restored by reducing by sulfuric
and nitrogenous pollution.
Global Warming
Deforestation
Global warming is an increase in earth’s average
temperature. CO2 and other gases are
collecting in the atmosphere, trapping the sun’s
heat and causing the planet to warm up. Global
warming could be a major disruptor to the Earth’s
homeostasis
Deforestation is the process where forests are
removed through logging or burning to use the
timber or the cleared and for agriculture.
Deforestation is a disruptor because it destroys
habitats and causes erosion. 46,000 – 58,000
square miles are lost each year. Deforestation
disrupts plant and animal habitats.
Homeostasis and the Environment
Photoperiodism
Biofilms
Photoperiodism is an organism’s response to
changes in the length of night. Examples include
flowers blooming, trees dropping their leaves and
animals migrating. Photoperiodism is a natural
process and it maintains homeostasis by
triggering responses in plants and animals.
Biofilms are surface-coating colonies or one or
more species of bacteria that work in metabolic
cooperation. They are natural occurrences and
cause cells to stick to one another. An example of
a biofilm is the layer of dental plaque that forms
on teeth overnight. In this example, the biofilm
can disrupt homeostasis by cause tooth decay.
Deliverable
• Piece of paper with the answer – remember: Keep it
short!!
• We will put them together on a slide and discuss.