ECOLOGY
Biodiversity
a. Define biodiversity and describe the effects on biodiversity of alteration of habitat
Biodiversity: the collective variety of organisms needed to sustain a particular ecosystem or community. Influenced by alternations in habitat through factors such as climate changes, pollution, influx of nonnative species, flood, and fire. Ecosystems work best when there are many different species with numerous interactions. A healthy ecosystem will be diverse and will be more protected in case of a natural disaster. If a particular species is wiped out due to a disaster, then there will be other species to take over some of the same roles in nutrient cycling and in food webs. However, if an ecosystem consists of a few species, then it is much more vulnerable if a disaster were to strike. If a species is lost due to, say, a flood, than the other species that depended on it may not be able to survive.
Biodiversity: the collective variety of organisms needed to sustain a particular ecosystem or community. Influenced by alternations in habitat through factors such as climate changes, pollution, influx of nonnative species, flood, and fire. Ecosystems work best when there are many different species with numerous interactions. A healthy ecosystem will be diverse and will be more protected in case of a natural disaster. If a particular species is wiped out due to a disaster, then there will be other species to take over some of the same roles in nutrient cycling and in food webs. However, if an ecosystem consists of a few species, then it is much more vulnerable if a disaster were to strike. If a species is lost due to, say, a flood, than the other species that depended on it may not be able to survive.
Energy Flow and Nutrient Cycles
a. Evaluate the importance of stability of producers, consumers, and decomposers
The relationship between predators and prey help to keep an ecological community stable. Predators keep populations in check. For example, wolves can help to keep a population such as elks or rabbits from overproducing. If they were allowed to reproduce without a predator to thin their numbers, then their population would become overwhelming. They would overgraze the vegetation. Its species would experience starvation and death. (see the link in the next section from BBC for an example on how wolves effected the elk population of Yellowstone National Park).
Decomposers are important as these plants and animals break down dead plants and animals into organic materials, which go back into the soil. Producers are the green plants that create their own food. These two groups are also very important and factors that may threaten the stability of producers and decomposers, jeopardizes the availability of energy and their ability to recycle matter. The soil is a very critical part of the ecosystem as it provides nutrients for the plants (producers). The soil also helps to anchor in the plants, absorb water, and provide a home for living organisms.
The relationship between predators and prey help to keep an ecological community stable. Predators keep populations in check. For example, wolves can help to keep a population such as elks or rabbits from overproducing. If they were allowed to reproduce without a predator to thin their numbers, then their population would become overwhelming. They would overgraze the vegetation. Its species would experience starvation and death. (see the link in the next section from BBC for an example on how wolves effected the elk population of Yellowstone National Park).
Decomposers are important as these plants and animals break down dead plants and animals into organic materials, which go back into the soil. Producers are the green plants that create their own food. These two groups are also very important and factors that may threaten the stability of producers and decomposers, jeopardizes the availability of energy and their ability to recycle matter. The soil is a very critical part of the ecosystem as it provides nutrients for the plants (producers). The soil also helps to anchor in the plants, absorb water, and provide a home for living organisms.
Interrelationships and Change in Ecosystems
a. Describe various species interactions (e.g., predator/prey, parasitism, mutualism, commensalism, competition)
Predator-Prey: this interaction is an advantage to the predator, death to the prey. A predator hunts another animal to use as food. This relationship plays a role in effecting the population diversity and community social organization as it removes those who could potentially reproduce. If predators did not exist, a single species could overpopulate. For example, if there were no wolves, then the deer population would increase which would effect the availability of food (grass) in the ecosystem. This decrease in grass may have a detrimental effect on the whole entire ecosystem. The predator-prey relationship can also allow evolution for preys to have escape mechanisms as well as for predators to evolve better capturing structors. For example, antelopes developed an incredible speed-burst ability to match the cheetahs' speed and the lions' camouflage and hunting tactics.
Here is short video from BBC explaining how reintroducing wolves back into the Yellowstone National Park effected the ecosystem:
http://www.bbc.com/future/story/20140128-how-wolves-saved-a-famous-park
Fun fact: one of the largest animals on Earth is the blue whale. It is predator to one of the tiniest animals on Earth which is the krill.
Parasitism: another relationship where one species benefits while the other is harmed. Endoparasites are internal and are categorized into three groups: roundworms (or nematodes), tapeworms (or cestodes), and flukes (or trematodes). Ectoparasites are external and includes fleas, lice, ticks, mosquitoes, and leeches. Ectoparasites have a structure that allows them to cling on or drill a hole through the skin. The goal of parasites is to absorb food from the body of the host and doing harm to the host. An example of a parasite is the guinea worm. This parasite lives in the human body and its infestation runs high in Africa and India. They are contracted when the human drinks water that is infested with water fleas that are almost invisible. The water fleas have eaten the worm larvae. As the water flea is ingested, the gastric juice kills the flea but not the larvae. The larvae passes through the stomach lining and after mating, the males die and the females that are carrying new larvae are carried to other parts of the body. The worms grow to 2-3 feet long and causes blisters to form on the feet and legs of the human body. The worms are able to emerge from these blisters and when the poor host enters a water source, they exit the host and enters the water, continuing the cycle. The guinea worm had two hosts, the water fleas and then the human body. Another parasite that uses multiple hosts is the Chinese liver fluke.
Mutualism: this relationship allows two organisms to live together as well as benefit from each other. One example of this type of relationship is the crocodile and the Egyptian plover. The crocodile is relieved of the irritation of leeches on its tongue by keeping its mouth open and allowing the Egyptian plover to eat them. Both species are able to live on their own without each other, but they provide a benefit to the other. Another example is the coevolution of pollinators and plants. Pollinators such as birds and bees seek out food from plants and as they do pick up pollen which they bring to the next plant. The pollinators are able to eat and the plants are able to reproduce.
Commensalism: In this relationship, one species lives off of another without doing any harm. It also does not help the other species. An example of this type of relationship is the suckerfish. It attaches itself to the underside of a shark, who then transports the suckerfish around. It also eats the food that is dropped by the shark. The shark is not harmed and is unaffected by the suckerfish.
Competition: increases as density of an environment increases as more individuals are in need of a finite amount of resources such as food, water, and space (habitat). Competition leads to individuals and species to develop either new ways to get their resources or minimizing their need for the resource.
b. Analyze the fluctuations in population size in an ecosystem due to the relative rates of birth, immigration, emigration, and death
Population does not experience a simple, linear growth. A population will start out slow as the number of reproduction organisms is still small. As the population grows, the number of individuals who are able to reproduce begins to increase. A population can then experience an exponential growth. If you were to graph this, it would look like a J-shaped curve. However, its population will be kept in check (Limiting Factors) by factors such as food, disease, predators, and space. Now, if we were to graph this population growth, it will show move of an S-shaped curve. The limiting factors define the growth rate and establishes a stable population size for an environment called the carrying capacity. The carrying capacity is the maximum number of individuals that a particular environment is able to sustain. This is established through a combination of limiting factors. In a population that is grown and developing and has resources, then the amount of births in the population will grow until it reaches the carrying capacity. When the population goes over the carrying capacity, then limiting factors may come into play. Deaths begin to exceed the number of births, bringing it below the carrying capacity. Fluctuations will occur as the number of organisms rise and fall below the carrying capacity due to the limiting factors.
Birth rate: number of live births per 1,000 people in a population in a given year
Death rate: number of deaths per 1,000 people in a population in a given year
Immigration: this is the movement of individuals into a population
Emigration: this is the movement out of a population
Population change= (births + immigration) - (deaths + emigration)
c. Analyze changes in an ecosystem resulting from changes in climate, human activity, introduction of nonnative species, and changes in population size
Predator-Prey: this interaction is an advantage to the predator, death to the prey. A predator hunts another animal to use as food. This relationship plays a role in effecting the population diversity and community social organization as it removes those who could potentially reproduce. If predators did not exist, a single species could overpopulate. For example, if there were no wolves, then the deer population would increase which would effect the availability of food (grass) in the ecosystem. This decrease in grass may have a detrimental effect on the whole entire ecosystem. The predator-prey relationship can also allow evolution for preys to have escape mechanisms as well as for predators to evolve better capturing structors. For example, antelopes developed an incredible speed-burst ability to match the cheetahs' speed and the lions' camouflage and hunting tactics.
Here is short video from BBC explaining how reintroducing wolves back into the Yellowstone National Park effected the ecosystem:
http://www.bbc.com/future/story/20140128-how-wolves-saved-a-famous-park
Fun fact: one of the largest animals on Earth is the blue whale. It is predator to one of the tiniest animals on Earth which is the krill.
Parasitism: another relationship where one species benefits while the other is harmed. Endoparasites are internal and are categorized into three groups: roundworms (or nematodes), tapeworms (or cestodes), and flukes (or trematodes). Ectoparasites are external and includes fleas, lice, ticks, mosquitoes, and leeches. Ectoparasites have a structure that allows them to cling on or drill a hole through the skin. The goal of parasites is to absorb food from the body of the host and doing harm to the host. An example of a parasite is the guinea worm. This parasite lives in the human body and its infestation runs high in Africa and India. They are contracted when the human drinks water that is infested with water fleas that are almost invisible. The water fleas have eaten the worm larvae. As the water flea is ingested, the gastric juice kills the flea but not the larvae. The larvae passes through the stomach lining and after mating, the males die and the females that are carrying new larvae are carried to other parts of the body. The worms grow to 2-3 feet long and causes blisters to form on the feet and legs of the human body. The worms are able to emerge from these blisters and when the poor host enters a water source, they exit the host and enters the water, continuing the cycle. The guinea worm had two hosts, the water fleas and then the human body. Another parasite that uses multiple hosts is the Chinese liver fluke.
Mutualism: this relationship allows two organisms to live together as well as benefit from each other. One example of this type of relationship is the crocodile and the Egyptian plover. The crocodile is relieved of the irritation of leeches on its tongue by keeping its mouth open and allowing the Egyptian plover to eat them. Both species are able to live on their own without each other, but they provide a benefit to the other. Another example is the coevolution of pollinators and plants. Pollinators such as birds and bees seek out food from plants and as they do pick up pollen which they bring to the next plant. The pollinators are able to eat and the plants are able to reproduce.
Commensalism: In this relationship, one species lives off of another without doing any harm. It also does not help the other species. An example of this type of relationship is the suckerfish. It attaches itself to the underside of a shark, who then transports the suckerfish around. It also eats the food that is dropped by the shark. The shark is not harmed and is unaffected by the suckerfish.
Competition: increases as density of an environment increases as more individuals are in need of a finite amount of resources such as food, water, and space (habitat). Competition leads to individuals and species to develop either new ways to get their resources or minimizing their need for the resource.
b. Analyze the fluctuations in population size in an ecosystem due to the relative rates of birth, immigration, emigration, and death
Population does not experience a simple, linear growth. A population will start out slow as the number of reproduction organisms is still small. As the population grows, the number of individuals who are able to reproduce begins to increase. A population can then experience an exponential growth. If you were to graph this, it would look like a J-shaped curve. However, its population will be kept in check (Limiting Factors) by factors such as food, disease, predators, and space. Now, if we were to graph this population growth, it will show move of an S-shaped curve. The limiting factors define the growth rate and establishes a stable population size for an environment called the carrying capacity. The carrying capacity is the maximum number of individuals that a particular environment is able to sustain. This is established through a combination of limiting factors. In a population that is grown and developing and has resources, then the amount of births in the population will grow until it reaches the carrying capacity. When the population goes over the carrying capacity, then limiting factors may come into play. Deaths begin to exceed the number of births, bringing it below the carrying capacity. Fluctuations will occur as the number of organisms rise and fall below the carrying capacity due to the limiting factors.
Birth rate: number of live births per 1,000 people in a population in a given year
Death rate: number of deaths per 1,000 people in a population in a given year
Immigration: this is the movement of individuals into a population
Emigration: this is the movement out of a population
Population change= (births + immigration) - (deaths + emigration)
c. Analyze changes in an ecosystem resulting from changes in climate, human activity, introduction of nonnative species, and changes in population size
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