ecology test 4

What hypothesis was tested regarding competition among desert rodents?

What hypothesis was tested regarding competition among desert rodents?

If competition among desert rodents is mainly for food, small granivorous rodent populations would increase when larger granivorous rodents are removed.

How did Gause demonstrate resource competition in a lab experiment?

By observing Paramecium species in the presence of different prey concentrations, showing one species dominating in competition.

How does competition impact the niches of small rodents?

Competition among small rodents can lead to changes in their niches, potentially affecting their population dynamics.

How do mathematical and laboratory models contribute to studying interspecific competition?

They provide a theoretical foundation for studying interspecific competition in nature.

Why are niches considered multi-dimensional?

Complete overlap in all dimensions would make species the same; niches can differ in various dimensions.

What does the Competitive Exclusion Principle propose?

Two species with identical niches cannot coexist indefinitely, leading to the prediction of different niches for coexisting species.

How does intraspecific competition affect herbaceous plants?

Competition for resources increases at higher population densities, often leading to mortality among competing plants.

What were the findings of the Paramecium competition experiment?

When grown together, one Paramecium species quickly declined due to resource competition.

How does competition restrict species in terms of their niche spaces?

Competition restricts species to their realized niches, but strong interactions can lead to evolutionary adaptive responses.

Can competitive interactions lead to evolutionary responses in populations?

Yes, strong and pervasive competitive interactions may produce an adaptive change in the competitor population, altering their fundamental niche.

What is the population growth equation related to competition?

Population growth equation includes parameters for species growth rates, carrying capacities, and competition effects.

How do niches of Darwins Finches relate to beak size and diet?

Beak size differences among ground finches translate into diet; individuals with deepest beaks feed on hardest seeds.

What are the modes of competition mentioned in the text?

Interference, intraspecific, and interspecific competition.

How did interspecific competition affect flour beetles in the experiments?

Interspecific competition restricted the realized niches of both flour beetle species to fewer environmental conditions.

What is the relationship between niche width and specialist/generalist species?

Specialists have narrow niche width, while generalists have broader niche width.

According to Gause, what happens when two species have identical niches?

They cannot coexist indefinitely; one will outcompete the other due to higher fitness, eventually leading to exclusion.

What factors contribute to intraspecific competition among arthropods?

Degree of competition due to population aggregations, rapid growth, and the mobile nature of their food supply.

What is the difference between fundamental and realized niches?

Fundamental niche is the entire range of conditions an organism can potentially occupy, while realized niche is where it actually exists due to factors like competition.

Where does competition occur in relation to limited resources?

Competition occurs where niches overlap regarding limited resources on the resource gradient.

What role does Balanus play in determining the lower limit of Chthamalus?

Balanus influences the lower limit of Chthamalus within the intertidal zone through niche restrictions.

Are relationships between predators and prey static or dynamic?

Relationships between predators and prey are dynamically changing over time, influenced by various factors.

What is the significance of the Red Queen Hypothesis in predator-prey interactions?

The Red Queen Hypothesis describes the need for constant evolution and adaptation in predator-prey interactions.

How does Rust fungus manipulate the growth of host mustard plants?

Rust fungus infects host plant, causing elongation and formation of pseudo-flowers attracting pollinators for outcrossing.

How do parasites alter host behavior in the ecosystem?

Parasites may alter host behavior to increase chances of transmission to the next host, sometimes leading to host death.

How did the caddisfly populations influence algal and bacterial populations in the stream?

Caddisfly larvae biomass can reduce algal abundance, impacting community structure in stream ecosystems.

What are some examples of small rodents mentioned in the text?

Examples: Kangaroo rat, Harvest mouse, Scorpion mouse

Why did mountain hare populations increase after the decline of fox populations?

Mountain hare populations increased due to reduced predation pressure from declining fox populations.

How is exploitation defined in the context of population interactions?

Interaction enhancing fitness of one while reducing fitness of exploited individual (e.g., predation, herbivory).

What is an example of parasites altering host behavior mentioned in the text?

Example: Spiny-Headed Worm (Acanthocephalans) altering amphipod behavior to increase predation risk.

How does the presence of a protozoan parasite influence competition in flour beetles?

Presence of protozoan parasite influences competition dynamics between flour beetles, impacting population densities.

How do Galapagos finches respond to competition?

Galapagos finches may respond to competition either allopatrically or sympatrically.

How do blister beetle larvae mimic burrowing bees?

Blister beetle larvae mimic female bee pheromones, swarm onto male and female bees during mating, and consume resources.

What are some examples of exploitative interactions mentioned in Chapter 14?

Predation, parasitism, pathogens influencing distribution, abundance, and structure of prey and host populations.

What are the factors influencing abundance cycles of snowshoe hares and their predators?

Factors include food availability, predator-prey interactions, and plant chemical defenses.

Did the results of the experiment on desert rodents support the hypothesis of increased granivorous rodent populations in response to the removal of larger granivorous rodents?

Reference: Insectivorous rodents would show little or no response.

How did Lindstrom et al. (1994) demonstrate the impact of mange mites on fox populations?

Mange mites caused hair loss and decline in fox populations, leading to indirect increase in mountain hare populations.

What did the study by Lamberti and Resh (1983) reveal about caddisfly larvae and their food supply?

Caddisfly larvae, though abundant, can reduce their own food supply (algae) due to high population numbers.

What is the Predator/Prey Paradox mentioned in the text?

The predator influences prey growth/survival while prey density impacts predator growth/survival, driving coevolution.

What are the different modes of competition mentioned in Chapter 13?

Modes: Interference (direct/aggressive), Intraspecific (own species), Interspecific (> 2 species)

What are parasitoids and how do they interact with their hosts?

Parasitoids consume and kill their hosts, impacting host populations and community dynamics.

How did fox populations change after being affected by mange mites?

Fox populations declined by 70%.

How do ectomycorrhizae contribute to improving plant access to nutrients?

Ectomycorrhizae form mantles around roots, increasing access to immobile nutrients for plants.

What are some of the overpopulation theories suggested by Keith regarding snowshoe hares and lynx cycles?

Decimation by disease and parasitism, physiological stress at high density, starvation due to reduced food.

What is J. J. Christians Stress Hypothesis?

Increase in population density leads to stress (competition), decreased reproduction, and increased mortality; decrease in population density results in decreased stress, increase in reproduction.

How can living in a large group act as a refuge for prey?

Living in a large group can act as a refuge by reducing individual probability of being eaten due to predator satiation.

How did Gause attempt to produce population cycles in the study involving P. caudatum and Didinium nasutum?

Gause attempted to produce population cycles by adding sediment as a refuge for P. caudatum after Didinium extinction.

How much of the mortality during peak densities can predation account for in snowshoe hares?

Predation can account for 60-98% of mortality during peak densities.

What is the concept of predator satiation defense?

Prey can reduce the probability of being eaten by living in dense populations, known as predator satiation defense.

Why do hosts and prey need refuges in the face of exploitation?

To persist in the face of exploitation, hosts and prey need refuges to avoid extinction.

How can the Ecology of Fear influence the behavior of prey animals like elk?

The Ecology of Fear can lead to alterations in prey behavior, where prey may avoid certain areas due to predators, affecting ecosystem dynamics.

What happened to the population of mountain hares (Lepus timidus) after the decline in the predator population?

Mountain hares increased 2-4 times after the predator population declined.

What did Utida study in terms of reciprocal interactions in adzuki bean weevils?

Utida studied reciprocal interactions in adzuki bean weevils over several generations.

What are some of the factors that can lead to cyclic population fluctuations discussed in the context of snowshoe hares and lynx?

Factors include reciprocal fluctuations, starvation, and weight loss leading to increased predation.

What is the relationship between plants and mycorrhizae as described in the context of the plant-water balance?

Mycorrhizae associations improve plant water balance by enhancing nutrient absorption and increasing surface area for nutrient exchange.

Who proposed abundance cycles driven by variation in solar radiation for snowshoe hares and lynx?

Elton proposed abundance cycles driven by variation in solar radiation.

How did Huffakers experimental design involve utilizing refuges in the study of spider mites?

Huffaker used wooden post launching pads as refuges to maintain population oscillations spanning 6 months.

What are some examples of mutualistic interactions mentioned in Chapter 15?

Plant partnerships, coral reef mutualisms.

What are the effects of mange mites (Sarcoptes scabiei) on foxes in Sweden?

Hair loss, deterioration, and death in foxes.

How do resource availability and fertilization impact the allocation of plants to roots?

Resource availability and fertilization influence plant allocation to roots, with reduced root allocation selected for better mycorrhizal competitor species.

What is the significance of Arbuscular Mycorrhizal Fungi (AMF) in plant-fungus associations?

AMF enhance nutrient uptake for plants and play a crucial role in nutrient exchange in mycorrhizal associations.

How do plants manage conflicts between mutualistic partners like ants and pollinators?

Plants avoid competition between mutualists by segregating resources such as nectar and bodies for different partners on different plant parts.

What roles do pollination, pollen transport, and nectar play in mutualistic relationships?

Pollination involves the transfer of pollen for reproduction, while nectar serves as a food reward for pollinators, facilitating mutualistic relationships between plants and pollinators.

How do yellow spotted salamanders engage in a mutualistic relationship with algae inside their eggs?

Yellow spotted salamanders benefit from algae inside their eggs by receiving oxygen and nutrients from the algae in return for protection and habitat.

What experimental evidence supports the mutualism between ants and Acacias?

Experimental evidence shows that ants significantly improve the plant performance of Acacias by reducing herbivorous insects and promoting shoot growth and survival.

What is the relationship between fertilization and root allocation?

Fertilization leads to less root allocation in plants.

What factors are considered in the evolution of mutualism according to Keelers models?

Keelers models consider relative costs and benefits in successful, unsuccessful, and non-mutualistic relationships for the evolution of mutualism.

How do corals control the rate of zooxanthellae population growth?

Corals control the rate of zooxanthellae population growth by altering organic matter secretion.

How does coral health benefit from the activity of crab mutualists?

Crab mutualists promote coral health by increasing the production of fat bodies in corals.

According to Johnson, can fertilization select for more or less mutualistic mycorrhizal fungi?

According to Johnson, fertilization can select for more or less mutualistic mycorrhizal fungi.

How do crustacean mutualists protect coral species according to Glynns findings?

Crustacean mutualists improve coral survival by deterring sea stars and promoting coral health through their activities.

How do extrafloral nectaries attract ants in temperate plant protection mutualism?

Extrafloral nectaries attract ants by providing them with a rich source of sucrose and amino acids.

What benefits do Acacia trees provide to ants in the mutualistic relationship?

Acacia trees provide ants with shelter, food in the form of Beltian bodies and foliar nectaries.

In nutrient-poor environments, why do many plants invest disproportionately in roots?

In nutrient-poor environments, many plants invest more in roots to compensate for the lack of nutrients.

What conditions are necessary for a facultative ant-plant mutualism to evolve and persist?

For facultative ant-plant mutualism to evolve and persist, the energy saved by ants from herbivore destruction must exceed the energy cost of producing extrafloral nectaries and nectar.

How do ants reciprocate the benefits to Acacia trees in the mutualistic relationship?

Ants provide protection to Acacia trees from competitors.

What benefits do higher nutrient levels, especially N and P, provide to zooxanthellae?

Higher nutrient levels, especially nitrogen and phosphorus, provide more nutrition to zooxanthellae, enhancing their growth and functions.

How do Acacia trees and ants engage in mutualism?

Acacia trees provide ants with shelter and food, while ants protect acacias from competitors.

How do zooxanthellae and corals engage in a mutualistic relationship?

Zooxanthellae provide carbohydrates and oxygen to corals, while corals provide zooxanthellae with ammonium.

How does resource availability control plant allocation?

Resource availability controls plant allocation by influencing the distribution of resources within the plant.

What are extrafloral nectaries and what role do they play in mutualistic relationships?

Extrafloral nectaries are nectar-producing structures outside flowers that provide food to insects in exchange for protection from predation.

What is the significance of the Lognormal Distribution of Abundance?

The Lognormal Distribution of Abundance graphs the abundance of species in collections as frequency distributions, indicating regularities in species abundance that hold regardless of the ecosystem.

What is the concept of disturbance in ecology?

Disturbance in ecology refers to discrete external events that disrupt ecosystems, communities, or populations, creating opportunities for new individuals or populations to establish.

How can communities be structured?

Communities can be structured based on physiognomic (physical structure), species composition (diversity), trophic (energy transfer, functional groups), and temporal (seasonal or diurnal activity) aspects.

What are the characteristics of disturbances?

Disturbances can be characterized by their size (area of impact), frequency (number of events per unit time), turnover (time between disturbances), intensity (physical force of the event), and severity (impact on the biota).

What types of species succeed in environments with no/rare disturbances?

In environments with no/rare disturbances, only good competitors succeed, leading to lower overall diversity.

What is resource division or niche partitioning?

Resource division or niche partitioning refers to the division of available resources among species in a community to reduce competition and promote coexistence.

What are examples of disturbances?

Examples of disturbances include wind, flood, fire, drought, animal overuse, farming, mining, timbering, pollution, and human activities.

Why is diversity higher when disturbance is intermediate?

Diversity is higher when disturbance is intermediate because it allows a variety of species to colonize, preventing competitive exclusion and favoring a mix of successful species.

How is diversity quantified using the Shannon-Wiener Index?

Diversity is quantified using the Shannon-Wiener Index: H’ = - Σ p(i) log e p(i), where p(i) is the proportion of the ith species, and s is the number of species in the community.

How is diversity affected by predation?

Predation can impact species diversity by influencing population sizes and interactions among species in a community.

What factors can affect diversity in communities?

Factors affecting diversity include climatic stability, resource division, predation, and disturbance.

How are animals often categorized based on?

Animals are often categorized based on their feeding strategy: when, where, what, and how they feed.

How does environmental complexity impact diversity?

Environmental complexity can increase diversity by providing varied niches and reducing competitive exclusion.

What is the Intermediate Disturbance Hypothesis?

The Intermediate Disturbance Hypothesis states that intermediate levels of disturbance promote higher diversity in communities, while both high and low levels of disturbance reduce diversity.

What was the focus of MacArthurs warbler feeding study?

MacArthurs warbler feeding study focused on how environmental complexity influences the feeding behavior and diversity of species.

What factors determine species diversity?

Richness and Evenness determine species diversity.

What role does environmental heterogeneity play in biodiversity?

Environmental heterogeneity contributes to biodiversity by providing diverse habitats and resources that support coexistence of multiple species.

What is an ecological community?

An ecological community is an assemblage of plant and animal populations that interact and influence one another.

Who developed the concept of distribution of commonness and rarity?

Frank Preston developed the concept of distribution of commonness and rarity.

What did Hutchinson observe about phytoplankton communities?

Hutchinson observed that despite competing for the same nutrients in relatively simple environments, many phytoplankton species coexist without competitive exclusion.