Ecology
Ecology is the study of the relationships that living things have with each other and the non-living things around them. In this Unit, it is important to remember that every living things need ENERGY to survive, grow, and reproduce but energy cannot be destroyed but recycled from one living thing to another to non-living things and back again.
Ecology is organized into different levels: Individual (one animal or plant)--> population (a group of the same species) --> Community ( groups so different species in an area)--> Ecosystem (living and non-living things in an area)--> Biomes--> Biosphere
Ecology is organized into different levels: Individual (one animal or plant)--> population (a group of the same species) --> Community ( groups so different species in an area)--> Ecosystem (living and non-living things in an area)--> Biomes--> Biosphere
Terms:
1) Biotic= living things [ex: deer, wolves, squirrel, owl, rabbit, bear, trees, grass, fungi, bacteria, etc.]
2) Abiotic= non-living things [sun, water, rocks, soil, wind, etc.)
BIODIVERSITY
It is important to have a high biodiversity (variety/assortments of livings things in an ecosystem)...just like it is important to have high genetic variety in Evolution. The more biodiversity an ecosystem has, the more stable it is (against changing conditions). Because everything in an ecosystem depends on something else to live, a single change-biotic or abiotic- could have a big impact on the rest. Species that have this big impact is called keystone species, in which it has an unusually large effect on its ecosystem. [ex: beavers-beavers in wetlands build dams and its their dams that provide ponds for living things and keep water level high for plants and so much more]
1) Biotic= living things [ex: deer, wolves, squirrel, owl, rabbit, bear, trees, grass, fungi, bacteria, etc.]
2) Abiotic= non-living things [sun, water, rocks, soil, wind, etc.)
BIODIVERSITY
It is important to have a high biodiversity (variety/assortments of livings things in an ecosystem)...just like it is important to have high genetic variety in Evolution. The more biodiversity an ecosystem has, the more stable it is (against changing conditions). Because everything in an ecosystem depends on something else to live, a single change-biotic or abiotic- could have a big impact on the rest. Species that have this big impact is called keystone species, in which it has an unusually large effect on its ecosystem. [ex: beavers-beavers in wetlands build dams and its their dams that provide ponds for living things and keep water level high for plants and so much more]
Energy in Ecosystems
Energy flows between biotic things and abiotic things. Within biotics, they are divided into Autotrophs and Heterotrophs. Autotrophs include producers (organisms that can make their own food/energy-such as plants) and Heterotrophs include consumers (organisms that need to eat other livings things or once-living things to get their energy-such as deers, wolves, hawks, humans, fungi, bacteria, buzzards, etc.)
But there are also organisms that feed on dead organisms, we call them decomposers and detritivores. Detritivores eat dead organic matters [ex: worms] and decomposers are detritivores that break down organic matter into simpler compounds and return the nutrients back into the soil/environment [ex: fungi and bacteria]. Decomposers are very important to an ecosystem because without them, nutrients are not returned for plants to absorb and so the cycling of energy will stop.
Trophic Levels, Food Chain, and Food Webs
Within an ecosystem, there are many feeding relationships between living organisms. The many feeding relationships is called a food web. If only a single feeding relationship is focused on in the ecosystem, then it's called a food chain.
The picture on the left is a food web because it shows the many different feeding relationships in this ecosystem. It includes autotrophs and heterotrophs. The arrows indicate the direction the energy is flowing to. For example, the arrow is going from the deer to the mountain lion. If you drew it the other, you would be saying that the energy is going from the mountain lion to the deer (or that the mountain lion is eaten by the deer...which is WRONG). The picture is also a food web because you can see that there are multiple arrows going away or toward one organism.
|
The 2 pictures on the left show food chains because it shows one possible feeding relationship for the owl. Notice that the food chain may or may not include decomposers, it depends on the ecosystem given. Of course, a stable ecosystem should have decomposers.
So, if we were to look back up at the food web above, what could be the different food chains of the mountain lion? 1: grass-->grasshopper-->shrew-->snake--> mountain lion-->fungi (and then back to grass) 2: grass-->rabbit-->snake-->mountain lion-->fungi (and then back to grass) Note: there is no food chain from grass to squirrel because there is no arrow pointing from grass to squirrel. |
As one organism feeds off of another, energy is transferred. However, the amount of energy transferred is a lot...about 90% less! Each feeding level is called a trophic "feeding" level. It is best represented through a pyramid. An energy pyramid starts wide at the base, symbolizing alot of energy, and as you go up the pyramid, energy decreases. So, why does energy decrease? Well, if you think about it, it makes sense. Energy is used to power all activities, so it would make sense that energy will be used up for bodily functions. Also, energy is lost as heat. As you sit and read this website, you are losing heat from your body and that's energy. When the organism is eaten, only whatever unused energy is transferred...and that's usually only 10%...the other 90% is used up.
Biogeochemical (Nutrient) Cycles
Other than energy, living things need many types of nutrients to survive: water, oxygen, carbon, nitrogen, etc. These matters are incorporated in living things but when decomposed, are returned to the soil where they can re-absorbed or cycled to the atmosphere and return to earth again. You will need to know at least 4 cycles for Mrs. Dinh (but other teachers may require you to know one more).
Oxygen Cycle
A simple cycle. Oxygen (O2) is produced through Photosynthesis by plants. Animals inhale oxygen and produce carbon dioxide (CO2) through Cellular respiration. Plants take in CO2 again and the cycle repeats.
Oxygen Cycle
A simple cycle. Oxygen (O2) is produced through Photosynthesis by plants. Animals inhale oxygen and produce carbon dioxide (CO2) through Cellular respiration. Plants take in CO2 again and the cycle repeats.
Water Cycle
Water comes down as Precipitation (rain, ice, snow). Water goes up to the atmosphere in 3 ways:
1) transpiration: from plants
2) evaporation: from bodies of water or land
3) respiration: from animals
In the atmosphere, water condenses in clouds and fall back down to earth again as precipitation.
Water comes down as Precipitation (rain, ice, snow). Water goes up to the atmosphere in 3 ways:
1) transpiration: from plants
2) evaporation: from bodies of water or land
3) respiration: from animals
In the atmosphere, water condenses in clouds and fall back down to earth again as precipitation.
Carbon Cycle
Carbon is one of the main building blocks of life-all living things are made of Carbon. It is in the ocean, air and even rocks. From the atmosphere, carbon goes down through Photosynthesis (so that means we need plants to bring down the Carbon....and yet we burn and cut down trees?) Carbon then goes from one organism to another as they are being eaten. Then, when the organism dies, it decomposes (by decomposers) and return carbon back into the soil so that plants can absorb. Carbon is also in fossil fuels within the ground (like oil). So when we burn gasoline, carbon is returned to the atmosphere. The burning of trees also adds carbon in the atmosphere. The picture below shows the carbon cycle and the many ways that Carbon goes back into the atmosphere: **we don't want too much carbon in the atmosphere because then it becomes pollution for us. There are different forms of Carbon. Carbon dioxide is used up by plants but Carbon monoxide (from cars) is toxic to us.
Carbon is one of the main building blocks of life-all living things are made of Carbon. It is in the ocean, air and even rocks. From the atmosphere, carbon goes down through Photosynthesis (so that means we need plants to bring down the Carbon....and yet we burn and cut down trees?) Carbon then goes from one organism to another as they are being eaten. Then, when the organism dies, it decomposes (by decomposers) and return carbon back into the soil so that plants can absorb. Carbon is also in fossil fuels within the ground (like oil). So when we burn gasoline, carbon is returned to the atmosphere. The burning of trees also adds carbon in the atmosphere. The picture below shows the carbon cycle and the many ways that Carbon goes back into the atmosphere: **we don't want too much carbon in the atmosphere because then it becomes pollution for us. There are different forms of Carbon. Carbon dioxide is used up by plants but Carbon monoxide (from cars) is toxic to us.
Nitrogen Cycle
Nitrogen is also an important element/molecule that makes up our DNA (amino acids). Nitrogen(gas) is absorbed into the soil when it rains and there are special bacteria called Nitrogen-Fixing bacteria that live near roots of legumes that can convert this nitrogen gas into another form called Ammonium. This process is called Nitrogen Fixation. Plants absorb ammonium and as organisms eat plants, nitrogen is passed on.
Nitrogen is also an important element/molecule that makes up our DNA (amino acids). Nitrogen(gas) is absorbed into the soil when it rains and there are special bacteria called Nitrogen-Fixing bacteria that live near roots of legumes that can convert this nitrogen gas into another form called Ammonium. This process is called Nitrogen Fixation. Plants absorb ammonium and as organisms eat plants, nitrogen is passed on.
Community Interactions (Symbiosis)
As you watched Planet Earth's: Jungle, you might have noticed the many different relationships that goes on in the rainforest/jungle. These relationships help organisms survive in their environment. These relationships are called Symbiosis: the close relationship between 2 or more species. There are 3 types of symbiosis (relationships):
1) commensalism: one organism benefits while the other is NOT harmed nor benefits from this relationship
ex) humans take milk without hurting or killing the cow.
ex) A spider building a web on a tree.
2) mutualism: BOTH organisms benefit.
ex) in Africa when the crocodile needs a plover bird to clean his teeth. Crocodile benefits from the bird because the teeth are cleaned and the bird benefits also because it gets to eat.
3) parasitism: one organism benefits and the other is harmed.
ex) tapeworms in dogs. The tapeworms feed off from the food the dog eat while the dog loses his nutrients and eventually dies.
1) commensalism: one organism benefits while the other is NOT harmed nor benefits from this relationship
ex) humans take milk without hurting or killing the cow.
ex) A spider building a web on a tree.
2) mutualism: BOTH organisms benefit.
ex) in Africa when the crocodile needs a plover bird to clean his teeth. Crocodile benefits from the bird because the teeth are cleaned and the bird benefits also because it gets to eat.
3) parasitism: one organism benefits and the other is harmed.
ex) tapeworms in dogs. The tapeworms feed off from the food the dog eat while the dog loses his nutrients and eventually dies.
Population Density and Growth
Population of organisms live either in packs or scattered. We call this Population Density.
Ecological Succession
adfasd