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EcologyChapters 3,4 & 6
3.1 What is ecology?
Ecology- the scientific study of interactions among organisms and between organisms and their environment.
*Turn to your partner and describe an “interaction” between two organisms.
Now describe an example of an organism “interacting” with its environment.
3.1 What is ecology?
Studying ecology can be as simple as examining a single organism, or as complex as the biosphere.
Biosphere- contains all of Earth including the land, water, air, atmosphere and all of the organisms on Earth.
3.1 What is ecology?
Scientists can study the following levels of organization from most simple to most complex:
1. Individual organism
2. Species-A group of organisms that is genetically similar and can breed together to produce fertile offspring.
3. Populations-A group of the same species that live in the same area (ex. a herd)
3.1 What is ecology?
4. Communities- several populations in the same area (ex. Different herds/packs in the same state).
5. Ecosystem-all of the organisms that live in a specific place along with all of their physical (nonliving) environment.
6. Biome- a group of ecosystems that have the same climate and similar organisms.
*Can you think of some examples of biomes?
Excellent!
Pics of biomes
3.2 Energy flow
Autotrophs vs. Heterotrophs
Organisms that can take energy from the sun.
Organisms that must consume other organisms for their energy.
Known as producers Known as consumers
Go through photosynthesis and cellular respiration to release energy from sun.
Go through cellular respiration to release energy from other organisms.
3.2 Energy flow
Food for thought: Are you considered an autotroph if you are a vegetarian?
3.2 Energy flow
Food Chains vs. Food Webs
A series of steps in which organisms transfer energy by eating and being eaten.
The feeding relationships between various organisms which forms a network of complex interactions.
Simple Complex
3.2 Energy flow
3.2 Energy flow
3.2 Energy flow
Trophic level-is each step in a food chain/web.
Producers always make up the first trophic level. Consumers make up the second, third, etc.
Why do you think producers always come first?
3.2 Energy flow
10% Rule- Only about 10% of the energy available within one trophic level is transferred to an organism at the next trophic level.
About 90% of the energy is lost as heat energy at each trophic level!
3.2 Energy flow
The 10% rule can be seen easily as a pyramid.
3.2 Energy flow
3.2 Energy flow
The 10% rule also applies to biomass.
Biomass- the total amount of living tissue within a given trophic level.
3.2 Energy flow
Plants and algae form the bottom of the pyramid because there are more of them on Earth (they can acquire energy from the sun more efficiently than by eating other organisms).
Conservation of energy- Energy can neither be created or destroyed (its just lost as heat!).
3.3 Cycling of Matter
Unlike energy matter is recycled within and between ecosystems.
Matter-is any substance that takes up space. (even as small as an atom)
Matter such as: water, carbon, nitrogen and phosphorus are cycled between the land, atmosphere and organisms.
How could water cycle in this way? Write down an example.
3.3 Cycling of Matter
3.3 Cycling of Matter
Carbon is a key element for storing energy for all organisms in the form of carbohydrates.
Carbon can be found in the atmosphere and oceans as CO2 .
Consumers need plants to convert the CO2 in the atmosphere to carbohydrates.
3.3 Cycling of Matter
How do organisms acquire energy from carbohydrates?
They break the bonds in between the carbons.
4.2 What Shapes an Ecosystem?
Most organisms find or evolve into a niche to avoid too much competition.
A niche- is the full range of physical and biological conditions which an organism lives and the way in which the organism uses those conditions.
4.2 What Shapes an Ecosystem?
For example:
4.2 What Shapes an Ecosystem?
Organisms that live in the same communities also interact in many ways, much like you interact with neighbors.
Some of the categories of interactions are:
Competition, predation, symbiosis, mutualism, commensalism and parasitism.
4.2 What Shapes an Ecosystem?
1. Competition- occurs when organisms of the same or different species attempt to use the same ecological resource at the same time. (table in notes: interaction, human example, animal example)
2. Predation- one organism captures and feeds on another organism.
4.2 What Shapes an Ecosystem?
3. Symbiosis- two species live closely together.
a. mutualism- both species benefit from the relationship.
b. commensalism- one member benefits the other is not helped or harmed.
c. Parasitism- one organism lives on or inside the other and harms it.
4.2 What Shapes an Ecosystem?
Main idea: these interactions between different organisms and their environment can affect the size of their population.
5.1 How Populations Grow
Exponential Growth vs.
Logistical Growth
Occurs when individuals reproduce at a constant rate
Occurs when a population’s growth slows or stops after a period of exponential growth.
Usually occurs under ideal conditions with unlimited resources.
Limited by carrying capacity- the max number of individuals an environment can support.
5.1 How Populations GrowExponential Growth
5.1 How Populations GrowLogistical Growth
5.1 How Populations Grow
5.1 How Populations Grow
Food for thought: If the rate of reproduction is constant, then why does the population shoot up over time?
What are some factors that might limit population growth in a logistic growth pattern?
6.3 Biodiversity
Biodiversity- the sum total of the genetically based variety of all organisms in the biosphere.
a. Ecosystem diversity- the variety of habitats and communities in the world.
b. Species diversity- the number of different species in the world.
c. Genetic diversity- all of the ways that organisms differ genetically (within their DNA).
6.3 Biodiversity
Why do we need a variety of organisms on Earth?
Provide humans with food, products, clothing, medicines, etc.
When one species becomes extinct it may affect many other species (think food web!).
When a species becomes extinct we will never know its hidden potential (i.e. drugs).
6.3 Biodiversity
Human activity can reduce biodiversity by:
Give an example of each-
a. Altering habitats
b. Hunting to extinction
c. Introducing toxins to a food web
d. Introducing foreign species
6.3 Biodiversity
a. Altering habitats- when humans/nature alters or destroys the habitat that an organism lives in.
6.3 Biodiversity
b. Hunting to extinction
Now illegal to hunt to extinction.
Hunting protected species is called poaching.
Ex: carrier/passenger pigeons hunted to extinction in early 1900’s.
6.3 Biodiversity (pg. 151)
Extinct species
Both Endangered species
6.3 Biodiversity
c. Pollution/toxins
Many forms of pollution can affect biodiversity such as smog, acid rain, garbage and agricultural runoff.
Biological magnification- when concentrations of harmful substances increase in higher trophic levels. Example: DDT pesticide.
6.3 Biodiversity
d. Introduced species
Humans sometimes unknowingly transport food/plants/animals from other parts of the world, which can upset the local food web.
Sometimes organisms are purposely introduced to control another species.
Invasive species- Organisms that when introduced to a new habitat reproduce rapidly and threaten local species.
6.3 Biodiversity
Food for thought: What could cause a species to grow exponentially in a new habitat when they did not in their habitat?
6.3 Biodiversity
Example of invasive species: Zebra muscles. Arrived via ship into the Great Lake in the 1980’s.
6.3 Biodiversity
What can we do to protect biodiversity?
Conservation- wise management of natural resources including the preservation of habitats and wildlife.
6.3 Biodiversity
Strategies for Conservation:
a. Protecting entire ecosystems
b. Captive breeding programs (zoos)
c. Protected areas- national/state parks
d. Ban hunting of endangered species
e. Enforce environmental laws
6.3 Biodiversity
Challenges:
a. Financial hardship on businesses (catch 22 because if not protected may not be there to use, i.e. fishing industry).
b. Economic costs to enforce laws.
6.4 The Future
Today much of the Earth’s land surface has been altered by human activities.
6.4 The future
One major change is a decrease in the ozone layer.
The ozone layer is a concentration of gases about 20-50 kilometers above the Earth.
It helps protect the Earth against some of the UV radiation from the sun.
6.4 The Future
In the 1970’s it was discovered that a product called CFC’s were responsible for much of the damage done to the ozone layer.
CFC’s were banned in products like hairsprays and refrigerators.
6.4 The Future
Another way humans have affected the biosphere is through greenhouse gases.
Greenhouse gases are pollutants released by cars, factories and homes such as: Carbon dioxide, methane and water vapor.
When these gases are released into the atmosphere they can form a layer around the Earth which traps the sun’s heat close to the surface. This is called the greenhouse effect.
6.4 The Future
6.4 The Future
So what if it gets warmer, I like summer! Melting glaciers= sea levels will rise.
Which means…
Increased temperatures= affects growing season.
Which means…
Some organisms may not be able to adjust to their new climate.
Which means…
6.4 The Future
Partner up and brainstorm 3 ways that humans can
a. Decrease our affect on the environment
b. Fix the damage that has already been done.
