Environmental Factors in Ecosystems

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Questions and Answers

Which of the following is NOT considered an abiotic limiting factor in terrestrial environments?

Temperature

Humidity

Predation (correct)

Soil pH

What relationship describes mutualism?

One species benefits while the other is harmed.

Both species are harmed by the interaction.

Both species benefit from the interaction. (correct)

One species benefits without affecting the other.

Which of the following biotic factors primarily leads to competition among species?

Area size

Availability of nesting sites (correct)

Soil nutrient content

Temperature fluctuations

What effect does predation typically have on prey and predator populations?

A balance often exists with cyclic fluctuations in both populations. Signup and view all the answers

Which of the following is an example of parasitism?

A tick feeds on a dog. Signup and view all the answers

What is a characteristic of a realized niche?

The actual conditions under which a species exists. Signup and view all the answers

Which abiotic factor is crucial for regulating aquatic life?

Salinity Signup and view all the answers

How does disease impact a population of organisms?

It typically reduces the population significantly. Signup and view all the answers

What is species richness primarily defined as?

The number of different species in an ecosystem Signup and view all the answers

Which of the following provides a quick evaluation of biodiversity but has limitations?

Frequency Table Signup and view all the answers

Which measure indicates the proportion of area covered by a species?

Percentage Cover Signup and view all the answers

Which index is used to measure species diversity taking both richness and evenness into account?

Shannon-Wiener Index Signup and view all the answers

Relative species abundance is calculated by which of the following formulas?

Number of target species / Total number of all species Signup and view all the answers

What does evenness refer to in an ecological context?

The degree to which different species are represented in an area Signup and view all the answers

In assessing percentage cover, which of the following is NOT a type?

Foliage Cover Signup and view all the answers

What limitation does species richness have?

It cannot indicate the health of the ecosystem Signup and view all the answers

Study Notes

Environmental Limiting Factors

Abiotic factors are non-living components of an environment that can limit population growth
- Terrestrial factors include:
  - Climate: Temperature, humidity, wind, cloud cover, sunlight
  - Soil: Thickness, structure, porosity, pH, nutrient content, salinity
  - Area size: Space available
- Aquatic factors include:
  - Salinity: Salt concentration
  - Turbidity: Water clarity
  - Depth: Distance from the water surface
  - Light: Availability of sunlight
  - Temperature: Water temperature
  - Oxygen: Dissolved oxygen levels
  - Currents: Water movement
  - pH: Acidity or alkalinity of water
Biotic factors are living components of an environment that can limit population growth
- Predator-Prey Interactions:
  - Predators consume prey, influencing prey population size
  - Typically, more prey than predators exist due to energy transfer limitations
- Competition: Organisms compete for resources such as food, nesting sites, and water
  - Competition can restrict organisms to their realized niche, which is smaller than their potential fundamental niche.
- Symbiosis: Relationships where at least one species benefits
  - Mutualism: Both species benefit
  - Commensalism: One species benefits, the other is unaffected
  - Parasitism: One species benefits at the expense of the other
- Disease: Pathogens (disease-causing agents) can damage or kill their hosts, impacting population size

Biodiversity Measurements

Species Richness: Number of different species present in an ecosystem
- Standard species richness is the number of species per unit area.
- Frequency tables can be used to quickly assess species richness in a particular area.
- Limitations include not identifying the species or indicating ecosystem health.
Relative Species Abundance: Proportion of one species compared to the total number of all species in an area
- Can be hard to use if species are difficult to distinguish
- Only provides information about a single target species
Percentage Cover: Estimate of the proportion of an area covered by an organism
- Measures the contribution and influence of each species in an area
- Types of percentage cover include basal, ground, leaf, and canopy cover
Species Evenness: Relative abundance of species compared to the total number of all species, indicating how evenly distributed species are
- Can be measured using percentage cover or the Shannon-Wiener Index.
- The Shannon-Wiener Index incorporates species richness and the relative abundance of each species into a single value.

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Description

Explore the various abiotic and biotic limiting factors that affect population growth in ecosystems. From climate and soil composition to predator-prey dynamics, this quiz covers essential concepts that influence living organisms in both terrestrial and aquatic environments.