Ecosystem Dynamics Flashcards
Draw the carbon cycle
Draw the nitrogen cycle
Draw the water cycle
Define ecological niche in terms of habitat, feeding relationships and interactions with other species
The ecological niche refers to a species’ unique position and function within an ecosystem, including its habitat requirements, feeding patterns, and interactions with other species. It encompasses the environmental conditions and resources necessary for survival, the species’ dietary preferences, and its role in the food web. Moreover, it involves the way the species interacts with other organisms, influencing its relationships, competition, and contributions to the ecosystem’s balance and dynamics.
What is the competitive exclusion principle?
The competitive exclusion principle, proposed by ecologist Gause, suggests that two species competing for the same limited resources cannot coexist indefinitely if ecological factors remain constant. Eventually, one species will outcompete and displace the other, leading to the elimination or exclusion of the weaker competitor from that particular niche. This principle underscores how direct competition impacts species distribution and survival within an ecosystem.
Define the term keystone species and describe what they do in a community.
Keystone species are organisms within an ecosystem whose presence significantly influences its structure and function, disproportionately affecting the community’s biodiversity. Their removal can cause significant changes or collapse in the ecosystem due to their pivotal role. They maintain species diversity, regulate population sizes, and have a disproportionate impact on the ecosystem’s stability, influencing various ecological interactions and processes crucial for the community’s health and integrity.
Define the term carrying capacity
the number of people, animals, or crops which a region can support without environmental degradation.
Why is the carrying capacity of a community determined by limiting factors and what are some examples of these factors?
The carrying capacity, a fundamental concept in ecology, is determined by limiting factors that regulate the maximum population size an environment can sustainably support. These factors control population growth by limiting resources or conditions necessary for survival and reproduction.
Examples of limiting factors include:
Food Availability: The quantity and quality of food resources in an ecosystem can restrict population growth.
Availability of Water: Access to water is crucial for survival, and scarcity limits the number of individuals a habitat can support.
Shelter or Nesting Sites: Availability of suitable habitats, shelter, or nesting locations can limit population sizes.
Predation and Disease: The presence and impact of predators and diseases can regulate population sizes.
Space or Territory: Limited space can restrict the number of individuals a habitat can accommodate.
Climate Conditions: Extreme temperatures, rainfall patterns, or other climate factors can limit population growth.
Carrying capacity is determined by the interplay of these limiting factors. As the population size approaches the carrying capacity, these factors impose constraints that prevent unlimited growth, ultimately stabilizing the population size at a level the environment can sustainably support.
Calculate the population of this community at the end of 2023:
2022 starting population: 213
60 births
45 deaths
20 immigrants
12 emigrants
236
What is the Lincoln index formula and how do you use it?
The Lincoln index, often used in ecological studies, estimates the total population size of an animal species based on the capture-mark-recapture method. This method involves capturing a sample of animals, marking them, and then recapturing a second sample, allowing estimation of the total population size.
The formula for the Lincoln index is:
N = (M * C) / R
Where:
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N = Estimated total population size.
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M = Total number of individuals marked in the first capture.
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C = Total number of individuals captured in the second round.
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R = Number of marked individuals recaptured in the second capture.
To use the Lincoln index:
Capture a sample of the population and mark (or tag) these individuals.
Release the marked individuals back into the population.
After some time, recapture a second sample of the population.
Count the total number of individuals captured in the second round (
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C) and the number of marked individuals recaptured (
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R).
Plug these values into the formula to estimate the total population size (
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N).
The accuracy of the estimate depends on several assumptions, including the assumption that marked individuals have had enough time to randomly mix with the population and that marking does not influence their survival or recapture rates.
Draw and logistic graph and an exponential graph and label each with their corresponding method of reproduction
S-curve = K-strategist
J-curve = r-strategist
If a community of humming birds is living in a rainforest, and a sudden influx of flowers occurs, what will happen to the carrying capacity of the humming birds?
It will increase
Define and explain ecological succession
Ecological succession is the gradual process of ecosystem change following a disturbance. It involves the predictable and sequential replacement of plant and animal communities over time. Primary succession occurs in areas devoid of soil, while secondary succession happens in areas where soil remains. Pioneer species establish, altering the environment, paving the way for new species until a stable climax community is reached, representing the endpoint of succession.
Identify, explain and contrast the two types of succession
The two types of ecological succession are primary and secondary succession.
Primary Succession:
Definition: Primary succession occurs in areas devoid of soil, such as bare rock, volcanic terrain, or glacial moraines.
Explanation: It begins with pioneer species like lichens and mosses that colonize the barren landscape, gradually breaking down rocks and organic matter to form soil. Over time, larger plants establish, creating a more complex ecosystem.
Secondary Succession:
Definition: Secondary succession occurs in areas where soil remains, such as after a forest fire, abandoned farmland, or cleared areas.
Explanation: It starts with the growth of new plants on preexisting soil. Disturbances like fire or human activities remove existing vegetation, allowing for rapid colonization by pioneer species. As these species grow and conditions change, more complex and diverse communities gradually re-establish.
Contrast:
Primary succession starts on bare substrates without soil, while secondary succession occurs on preexisting soil. Primary succession takes longer as it involves the formation of soil, while secondary succession progresses relatively faster due to the presence of already established soil and seeds. Both processes lead to the development of more complex and diverse ecosystems over time.
What are the 4 features of pioneer species that make them effective colonisers?
Ability to fixate nitrogen, tolerance to extreme conditions, rapid germination of seeds, ability to photosynthesise
