Ecology Flashcards

Flashcards based on lecture notes covering topics from population ecology to ecosystem ecology and anthropogenic impacts.

What was the primary finding of Hypothesis 1 in the paper discussion regarding interspecies competition among ant species?

Both species had decreased survivorship in the presence of competitors. The species that outcompetes was not predicted correctly.

What are the key conclusions from the ant species competition study regarding resource allocation and invasive species?

Multiple species in competition with each other will exhibit resource allocation, and dominance over nests lays the groundwork for invasive species to outcompete native species.

What is the difference between direct and indirect effects in multi-species interactions?

Direct effects occur between two species without an intermediate, while indirect effects involve some intermediate species.

What are trophic cascades, and can you give an example?

Indirect effects initiated by a predator, such as crabs eating snails leading to increased seagrasses.

What defines a keystone species, and what is an example?

Keystone species have a disproportionate effect on the abundance and strength of a community, such as sea otters and sea urchins.

What role do food webs play in ecological studies?

Adding complexity to food chains and reflecting the reality of species that feed on similar consumer guilds within the same trophic level.

What methods are used to determine the structure of food webs?

Observational studies, gut content analysis, fecal analysis (metabarcoding), and stable isotopes.

What is the difference between species richness and species evenness?

Species richness refers to the number of species in a sample site, while species evenness is the distribution of relative abundance for species in a sample/site.

What is the purpose of the Shannon's Diversity Index (H')?

Useful for comparing sites, with H’ maximized when all species have the same relative abundance.

In the Species-Area Relationship, what do S, A, c, and z represent?

S = species richness, A = area, c = number of species expected in one unit of area, z = value <1 indicating how fast species accumulate with area.

What are the key assumptions behind the Chao1 Index?

Assumptions include: more singletons indicate more undiscovered species and that all species having at least two individuals present means there are no more undiscovered species to sample.

What are alpha, beta, and gamma diversity?

Local (# species in all habitats within a small/homogenous region), Regional (# species in all habitats within a geographic region), and Beta (difference in species composition between locations).

Define functional traits, functional richness, and functional redundancy.

Functional traits are characteristics of species that describe their ecological role; functional richness is the number of different functional traits in a community, and functional redundancy refers to species with similar functional traits within the ecosystem.

What is the definition of movement in movement ecology?

A to B, not mechanism; improves individual or group fitness.

What is migration and what are its benefits?

Round trip group movement. Reproduction benefits in one area and survival better in another.

What is dispersal and what are its benefits?

Individual to new location, colonize new areas/seek better habitat, find mates, decrease inter-familial competition.

What is the Ideal Free Distribution?

Individuals disperse to maximize individual benefits/per capita benefit.

What are the assumptions of the Levins Metapopulation Model?

Births and deaths constant, subpopulations exist in two states: occupied or empty, only occupied patches produce dispersing individuals, dispersing individuals equally likely to disperse into occupied or empty patches, all patches equally accessible to dispersing individuals, empty patches get colonized based on proportion of occupied patches, patches go extinct at constant rate, e (independent of proportion occupied patches).

What are the assumptions for the equilibrium theory from island biogeography?

Rate of colonization decreases as diversity increases; rate of extinction increases as diversity increases.

What are Interdependent Communities?

Species depend on one another to exist; remove one species, the entire community suffers.

What are Independent Communities?

Species depend on habitat requirements rather than other species.

What is a Seral Stage?

Each stage of community change during the process of succession.

What is Primary Succession?

Development of communities in habitats that are initially devoid of plants and soils.

What is Secondary Succession?

Development of communities that contain no plants but do have organic soil.

What is the difference between species found in different stages of succession?

Early successional species are usually R-selected while late successional species are K-selected.

What characteristics do plants in the early stages of succession demonstrate?

Good dispersers, rapid growth & reproduction, tolerant of harsh abiotic conditions but are poor competitors and shade intolerant.

What characteristics do plants in the late stages of succession demonstrate?

Bad dispersers, slow growing/invest in below-ground biomass, intolerant of harsh abiotic conditions but are large in size as adults and shade tolerant.

What are three models of succession?

Facilitation, Inhibition, and Tolerance models.

What is Ecosystem Ecology?

Study of the transfer of energy/matter among living and non-living components within and between systems.

How does photosynthesis affect the carbon cycle?

Photosynthesis "fixes" carbon, making it usable for humans to yield glucose and oxygen.

What is the equation for Net Primary Productivity (NPP)?

NPP = GPP - Respiration

How is primary productivity measured in terrestrial ecosystems?

Light vs. Dark Method measuring changes in CO2 in light and dark conditions to isolate photosynthesis and respiration rates.

What is Secondary Production?

The amount of energy converted by herbivores used for energy, growth, and reproduction.

What regions have the highest productivity and why?

Tropical regions and along coasts are the most productive regions and act as carbon sinks due to heavy rainfall, warm temperatures, and more assimilation than respiration.

What are the main limiting nutrients in ecosystems?

Nitrogen and phosphorus.

What is consumption efficiency and assimilation efficiency?

Consumption Efficiency is the % energy of one trophic level consumed by the next higher trophic level; Assimilation Efficiency is the % consumed energy that is assimilated.

How do you describe ecological efficiency?

% net production from one trophic level compared to the next lower trophic level

What are the benefits of cloning and reintroduction of species?

Introduces new genetic diversity to increase the population's resilience.

What were the findings of the paper discussion regarding declining otter populations?

Characterized by a decrease in # of otters via increased death rates caused by killer whale predation.

What does the Leslie Matrix study tell us about decrease in sea urchin populations?

Significant bottom-up effects that would result in a decrease in the entire chain.