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Questions and Answers
What type of interaction occurs when two species compete for the same limited resource?
What type of interaction occurs when two species compete for the same limited resource?
Which of the following is NOT a type of interspecific interaction?
Which of the following is NOT a type of interspecific interaction?
In the context of community ecology, what does interspecific competition result in?
In the context of community ecology, what does interspecific competition result in?
Which of the following best describes the term 'community' in ecology?
Which of the following best describes the term 'community' in ecology?
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What is the primary focus of community ecology?
What is the primary focus of community ecology?
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What does the variable $N_0$ represent in community ecology?
What does the variable $N_0$ represent in community ecology?
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Which equation represents the relationship involving births in population ecology?
Which equation represents the relationship involving births in population ecology?
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In which scenario would a discrete model of population growth be appropriate?
In which scenario would a discrete model of population growth be appropriate?
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What does the term 'intrinsic rate of increase' refer to?
What does the term 'intrinsic rate of increase' refer to?
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Which of the following correctly describes the model involving parental generation?
Which of the following correctly describes the model involving parental generation?
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What happens during competitive exclusion?
What happens during competitive exclusion?
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What is meant by resource partitioning?
What is meant by resource partitioning?
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What defines the fundamental niche of an organism?
What defines the fundamental niche of an organism?
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What results from character displacement?
What results from character displacement?
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What does the realized niche refer to?
What does the realized niche refer to?
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What is the primary purpose of cryptic coloration in prey species?
What is the primary purpose of cryptic coloration in prey species?
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What is the difference between Batesian and Mullerian mimicry?
What is the difference between Batesian and Mullerian mimicry?
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Which of the following statements about mimicry is true?
Which of the following statements about mimicry is true?
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How does mimicry potentially benefit non-toxic species?
How does mimicry potentially benefit non-toxic species?
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What does the term 'advertise bad taste/toxicity' refer to in the context of animal defense strategies?
What does the term 'advertise bad taste/toxicity' refer to in the context of animal defense strategies?
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What is a characteristic of ectoparasites?
What is a characteristic of ectoparasites?
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Which interaction type benefits both species involved?
Which interaction type benefits both species involved?
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What does the Shannon diversity index measure?
What does the Shannon diversity index measure?
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How do trophic levels relate to energy flow in an ecosystem?
How do trophic levels relate to energy flow in an ecosystem?
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What limits the length of food chains in communities?
What limits the length of food chains in communities?
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Which type of ecological succession is characterized by the growth of a community from bare rock?
Which type of ecological succession is characterized by the growth of a community from bare rock?
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In what way can keystone species influence community structure?
In what way can keystone species influence community structure?
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What is an example of a positive interaction where one species benefits without affecting the other?
What is an example of a positive interaction where one species benefits without affecting the other?
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What type of consumers are tertiary consumers in an ecosystem?
What type of consumers are tertiary consumers in an ecosystem?
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Which of the following is a type of disturbance that can impact communities?
Which of the following is a type of disturbance that can impact communities?
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Which of the following statements about mutualism is true?
Which of the following statements about mutualism is true?
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What distinguishes primary consumers from other trophic levels?
What distinguishes primary consumers from other trophic levels?
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What is a key benefit of having a highly diverse community?
What is a key benefit of having a highly diverse community?
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What role do predators play in maintaining healthy populations?
What role do predators play in maintaining healthy populations?
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Which of the following options describes an exploitation relationship?
Which of the following options describes an exploitation relationship?
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How does natural selection relate to predation?
How does natural selection relate to predation?
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What is one major evolutionary response to predation that prey species exhibit?
What is one major evolutionary response to predation that prey species exhibit?
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What can be a consequence of predator-prey interactions on population dynamics?
What can be a consequence of predator-prey interactions on population dynamics?
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In what way can competition among barnacles affect their realized niche?
In what way can competition among barnacles affect their realized niche?
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What is an 'arms race' in the context of predator-prey interactions?
What is an 'arms race' in the context of predator-prey interactions?
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Why are predators often perceived negatively despite their ecological benefits?
Why are predators often perceived negatively despite their ecological benefits?
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What occurs when two species shift to avoid direct competition?
What occurs when two species shift to avoid direct competition?
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What is the difference between a fundamental niche and a realized niche?
What is the difference between a fundamental niche and a realized niche?
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What phenomenon occurs when closely related species diversify to minimize competition?
What phenomenon occurs when closely related species diversify to minimize competition?
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Which of the following best describes the disadvantages for the winner in a competitive interaction?
Which of the following best describes the disadvantages for the winner in a competitive interaction?
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What is a potential consequence of competitive exclusion on species diversity?
What is a potential consequence of competitive exclusion on species diversity?
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What impact does competition have on species trying to access limited resources?
What impact does competition have on species trying to access limited resources?
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Which statement accurately describes interspecific competition?
Which statement accurately describes interspecific competition?
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In a community, what is the primary resource that species compete for?
In a community, what is the primary resource that species compete for?
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How can intra-specific competition manifest among individuals of the same species?
How can intra-specific competition manifest among individuals of the same species?
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What distinguishes competition from exploitation in ecological interactions?
What distinguishes competition from exploitation in ecological interactions?
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What does the variable $N_p$ signify in population ecology?
What does the variable $N_p$ signify in population ecology?
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Which equation best describes the model for discrete population growth?
Which equation best describes the model for discrete population growth?
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Which aspect describes intrinsic rate of increase correctly?
Which aspect describes intrinsic rate of increase correctly?
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What best characterizes continuous population growth in ecological models?
What best characterizes continuous population growth in ecological models?
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In community ecology, what happens when overlapping of discrete and continuous growth occurs?
In community ecology, what happens when overlapping of discrete and continuous growth occurs?
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What is the primary function of cryptic coloration in prey species?
What is the primary function of cryptic coloration in prey species?
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Which type of mimicry involves a harmless species mimicking a harmful one?
Which type of mimicry involves a harmless species mimicking a harmful one?
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Which statement best describes Mullerian mimicry?
Which statement best describes Mullerian mimicry?
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What does the phrase 'advertise bad taste/toxicity' signify in animal defense mechanisms?
What does the phrase 'advertise bad taste/toxicity' signify in animal defense mechanisms?
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How does mimicry benefit non-toxic species in the wild?
How does mimicry benefit non-toxic species in the wild?
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Which of the following statements best describes herbivory?
Which of the following statements best describes herbivory?
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What is one primary role of chemical defenses in plants against herbivores?
What is one primary role of chemical defenses in plants against herbivores?
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Which of the following best exemplifies morphological defenses in plants?
Which of the following best exemplifies morphological defenses in plants?
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What can be a result of the evolutionary arms race between plants and herbivores?
What can be a result of the evolutionary arms race between plants and herbivores?
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Which of the following is NOT an example of a plant defense mechanism?
Which of the following is NOT an example of a plant defense mechanism?
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What characterizes endoparasites in comparison to ectoparasites?
What characterizes endoparasites in comparison to ectoparasites?
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What is one of the main functions of a keystone species in an ecological community?
What is one of the main functions of a keystone species in an ecological community?
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In a food web, which term best describes the role of primary producers?
In a food web, which term best describes the role of primary producers?
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What is a characteristic feature of mutualistic interactions?
What is a characteristic feature of mutualistic interactions?
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What type of succession takes place when a community is regrowing after a disturbance that left the soil intact?
What type of succession takes place when a community is regrowing after a disturbance that left the soil intact?
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What does the term 'species richness' refer to in an ecological community?
What does the term 'species richness' refer to in an ecological community?
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Which of the following accurately describes the effect of disturbances on communities?
Which of the following accurately describes the effect of disturbances on communities?
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Which statement best describes the relationship between trophic levels and energy transfer in an ecosystem?
Which statement best describes the relationship between trophic levels and energy transfer in an ecosystem?
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What defines a community's 'relative abundance'?
What defines a community's 'relative abundance'?
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What is an example of a disturbance that could impact an ecological community?
What is an example of a disturbance that could impact an ecological community?
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How does the Shannon diversity index (H) function in community ecology?
How does the Shannon diversity index (H) function in community ecology?
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What is the primary role of fungi in lichen partnerships?
What is the primary role of fungi in lichen partnerships?
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Study Notes
Community Ecology
- Community: a collection of different species, living and potentially interacting in a specific area
- Interspecific interactions: interactions between different species
- Intraspecific interactions: interactions within the same species
Exponential Growth
- Discrete with overlap: new births added to previous generation; parents reproduce
- Discrete with no overlap: new births after parental generation dies
- Continuous: no time separation between generations
- Exponential Growth equation: Nt = N0ert
- Nt = population size at time t
- N0 = initial population size
- r = intrinsic rate of increase
- t = time
- Exponential Growth equation: Nt = N0ert
Competition (-/-)
- Two or more species compete for the same limited resource(s) -- food, shelter, territory, etc.
- Competitive exclusion: one species is outcompeted and becomes locally extinct
- Resource partitioning: species shift to avoid direct competition
Competition Continued
- Fundamental niche: the ideal space an organism can occupy based on its needs, resources and adaptations
- Realized niche: the actual space an organism occupies due to competition and other limiting factors
- Character displacement: closely related species diverge to avoid direct competition
- can lead to new species
- Species diversify to avoid competition
Exploitation (+/-)
- Relationship where one species consumes some or all of another
- Predation, herbivory, and parasitism
- Impacts of predators
- Removing sick or weak individuals
- Preventing overpopulation
- Maintains healthy population
Predation Effects
- Aposematic coloration: warning colors to advertise bad taste or toxicity
- Cryptic coloration: camouflaging to hide from predators
- Mimicry: resembling another species
- Batesian mimicry: harmless species resembles a harmful species
- Müllerian mimicry: two or more harmful species resemble one another
Herbivory
- Feeding on plants; doesn't always need to kill the plant
- Results in natural selection among plants due to evolutionary arms races
- Plants defend themselves against herbivores through chemical or morphological adaptations
- Chemical defenses: toxins, bitter compounds (e.g., caffeine, strychnine, opiates)
- Morphological defenses: thorns, spines, hairs, difficult to digest compounds (e.g., silica in plants can shred animal guts)
Parasitism
- Feeding on a host while it remains alive
- Ectoparasites: live outside host
- Endoparasites: live inside host
- Impacts of parasites
- Often leads to adaptations for complex life cycles and multiple hosts
- Often leads to significant physical adaptations
- Impacts food chains
Positive Interactions (+/+ or +/0)
- Mutualism (+/+): both species benefit from interaction
- Commensalism (+/0): one species benefits, the other is unaffected
Community Structure
- Species diversity: the variety of organisms making up a community
- Species richness: the number of different species
- Relative abundance: proportions of different species
- Shannon diversity index (H): a measure of diversity; a higher value indicates a more diverse community
Community Roles
- Food web: visual representation of feeding relationships
- Trophic level: grouping of organisms that access energy at the same number of steps from the original energy source (sun)
Trophic levels
- Primary producers (autotrophs)
- Primary Consumers (herbivores)
- Secondary Consumers (predators that eat herbivores)
- Tertiary Consumers (predators that eat secondary consumers)
- Quaternary Consumers (predators that eat tertiary consumers)
Limits to Food Chain Length
- Inefficient energy transfer between trophic levels limits the number of steps/levels in a food chain
- Fewer carnivores than herbivores at higher trophic levels
- Expressed as a comparison of biomass (total mass of all organisms)
Community Control
- Keystone species/ecosystem engineers have disproportionate impacts
- Community complexity: resilient communities tolerate invasive species and removals better than less diverse communities
Disturbance and Succession
- Disturbance: events that change communities by removing organisms or altering resource availability
- Fires, floods, droughts
- Succession: recovery process following disturbance
- Primary succession: from scratch
- Secondary succession: re-growing community
Disturbance Isn't Necessarily Bad
- Intermediate Disturbance Hypothesis: moderate disturbances lead to more diversity
Other Factors Influencing Communities
- Humans: biomes/productivity, size, isolation
- Pathogens: can heavily impact community composition
- Island equilibrium model: island size, isolation control immigration and extinction rates
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Description
Test your knowledge of community ecology concepts with this quiz! Explore various types of interactions, the focus of community ecology, and key population dynamics. Perfect for students studying ecology at different levels.