Ecology Exam 3
Neutral
(00) Neither species affects the other e.g. rabbits, deer, and frogs all live together in a field with no interaction between each other
______________________ mimicry occurs when many unpalatable or venomous species share a similar color pattern.
Mullerian
When is a fundamental niche larger than a realized niche? When can a realized niche be larger than a fundamental niche?
Mutualism and Commensalism can result in a realized niche that is larger than the fundamental niche.
Under certain conditions, __________________ fungi live in the roots of many species of plants and have a mutually beneficial relationship with plants.
Mycorrhizae
Mutualism
(++) Both species mutually benefit e.g. pollination biology
Predation
(+-) One species feeds on another, killing it. E.g. bear feeding on fish
Parasitism
(+-) One species feeds on another, reducing its fitness but not killing it e.g. malaria, scabies
Parasatoidism
(+-) One species uses another for reproduction, and its larvae feed on it, eventually killing it e.g. moths lay one or many eggs on or in caterpillars
Commensalism
(+0) One species benefits and the other is unaffected e.g. an orchid growing on a tree limb
Competition
(--) Both species compete for resources e.g. cheetahs and lions
Ammensalism
(-0) Asymmetric competition e.g. a taller plant species shades a shorter plant species
What effect does environmental heterogeneity have on community structure?
- Affects community structure - A landscape has a mix of concentrations of multiple species of plants and animals (biological), or of terrain formations (geological), or environmental characteristics (e.g. rainfall, temp., wind) filling its area
Describe the factors that may potentially affect an animal's decision about how it forages in a food patch.
- Hunting profitability - Risk of predation
Discuss the relative difficulties of studying interspecific competition in a laboratory and in the field.
- In the lab, variables are controlled - Variables are not controlled in the field - In the field, niche partitioning: species sharing resources
Describe three types of responses by animal hosts to minimize the impact of parasites.
- Inflammatory response: release of histamines that act as a chemical alarm - Internal cyst: can encase the parasite - Immune response: antibodies affect the ability of the parasite to feed, spread, and reproduce, but do not have to kill it
Describe two examples of mutualism involving the transfer of nutrients.
- Seed dispersal - Pollinator relationships
What is a guild?
A measurement that relates number and relative abundance of species within a community. This mix of species defines the biological structure of a community. 1. count of all species 2. relative abundance of each species in a community
What is meant by a "null model" in community ecology
A null model assumes that community structure is based on independent responses to the abiotic environment. i.e. interspecific interactions not important - provides a useful framework for comparing actual patterns
Discuss the ecological differences between early successional species and late successional species within a sere.
A sere is the sequence of communities in succession (e.g. grass to shrub to forest) Early successional species are initial colonists, or pioneer species - high growth rates - smaller size - high degree of dispersal and colonization - high rates of per capita population growth Late successional species arrive later - longer life spans - larger size - lower rates of dispersal and colonization - lower rates of per capita population growth
What is a chronosequence?
A series of sites within an area that are at different successional stages (seral stages)
When predators come together in areas of high prey density, it is referred to as ________________.
Aggregated response
Chemical interaction competition in plants is called ______________.
Allelopathy
Discuss the costs and benefits of each of the three hunting methods employed by predators.
Ambush: minimal energy, low success rate e.g. snake waiting on a long Stalking: pursuit time is minimal, most time and energy spent finding prey e.g. cheetah, crane (bird catching fish) Pursuit: pursuit time is long, most time and energy are spent capturing and handling prey
What is the difference between autogenic and allogenic factors that affect community succession?
Autogenic: change results directly from organisms - trees determine light profile in forest Allogenic: change results from physical (abiotic) process - decline in temp. with increased elevation
Compare and contrast two types of mimicry.
Bayesian: some animals evolve coloration that resembles toxic species e.g. butterfly, snake Mullerian: unpalatable, venomous, or toxic species share a similar color pattern e.g. bee, wasp
A shift in the morphology, behavior, or physiology of a species in response to resource competition is referred to as _______________ displacement.
Character
The process in which a network of species undergoes reciprocal evolutionary change through natural selection is referred to as ___________________.
Coevolution
________________ competition results when individuals of one species inhibit individuals of another by using up a shared resource.
Consumptive
The host species in which a parasite becomes an adult and reaches maturity is referred to as a(n) ______________ host.
Definitive
What is the difference between direct and indirect transmission of a parasite?
Direct: pass from infected person to not infected person via physical contact (blood or bodily fluid) Indirect: no direct contact (contaminated clothing, bedding, food)
What does it mean for a species to be "dominant" in a community?
Dominant: makes up more biomass Abundant species may not be dominant
According to the competitive exclusion principle, what will happen when populations of two species live in the same place and have exactly the same ecological requirements?
Environmental conditions remain constant
A mutualism in which two species benefit when living together but can survive when apart is referred to as a(n) __________________.
Facultative mutualist
The relationship between the per capita rate of consumption and the number of prey is known as the predator's _________________ response.
Functional
Plant parasites that are photosynthetic but draw water and nutrients from their host plant are referred to as ________________.
Hemiparasites
A relationship that affects the populations of two or more species adversely is referred to as _____________ competition.
Interspecific
Adaptive Radiation
Interspecific interactions can contribute to evolution of ecotypes. - populations that are adapted to their local environment - development of mammals after the extinction of dinosaurs
Define a keystone species. Give an example of the changes that may occur within a community when a keystone species is removed.
Keystone species: has a disproportionate impact on the community relative to its abundance. Removal will lead to changes in community structure and loss of biodiversity. - create or modify habitats - influence interactions among other species
What would a rank-abundance curve look like for a community with low evenness?
Low evenness: steep slope High evenness: gradual slope Low richness: short curve High richness: long curve
A species that consumes both plant and animal tissue is called a(n) _________________.
Omnivore = eats both plants and animals Herbivores = eats just plants Carnivores = eats just meat
What is the difference between a parasite and a parasitoid?
Parasite: lives on to in another organism, the host, causing it harm but does not kill it. Parasitoid: an organism that lives in close association with its host at its expense, later on kills the host.
The length of a butterfly tongue perfectly matches the nectar tube of a flower it pollinates. This is an example of __________________.
Specialization or Coevolution
When prey produce so many offspring in a short period of time that predators can attack only a fraction of them, it is referred to as ________________.
Predator satiation
When prey produce so many offspring in a short period of time that predators can attack only a fraction of them, it is referred to as ___________________.
Predator satiation
What is the difference between primary and secondary succession?
Primary: occurs at a location that was not previously occupied by a community, a newly exposed surface Secondary: occurs at a location that was previously occupied by a community
What is the difference between qualitative and quantitative inhibitors? Give examples.
Qualitative: toxic secondary compounds; interfere with metabolic pathways (nicotine, caffeine) Quantitative: secondary compounds produced in large quantities; interfere with metabolic pathways
When a species expands its niche in response the the removal of a competitor, the species has experienced competitive ________________.
Release
Coexisting species of wild cats differ in the size of their canine teeth, which corresponds to differences in their preferred species of prey. This outcome is most likely the result of __________________.
Resource partitioning: similar species can coexist in the same habitat because they partition available resources. e.g. plants use nutrients in different proportions and tolerate different levels of light. - Each species uses a portion of the resource not used by the other it lives with. - Same as meso predator release - lower and higher species can expand when middle is moved out.
When an ecologist compares the diversity of different communities by counting the number of species within each community, the measure of diversity being used is called _________________.
Species richness
What is the intermediate disturbance hypothesis? When might it be useful?
The highest species diversity is seen at intermediate frequencies of disturbance relationship between diversity and disturbance.
What is the difference between top-down and bottom-up control?
Top-down: top trophic levels (predator) determine abundance/structure of the lower trophic levels Bottom-up: lower trophic levels determine abundance/structure of the higher trophic levels
