Biology Chapter: Ecosystems and Food Chains

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Questions and Answers

What is the first step that must be taken when rehabilitating a mine site?

Refill the pit with landfill or water

Introduce vegetation in stages

Spread stockpiled soil over the area

Clear and care for vegetation, seeds, and seedlings (correct)

What is a consequence of ploughing soil during agricultural practices?

Improved water retention

Increased rates of erosion (correct)

Reduction in weed growth

Increased soil fertility

Which methodology can help minimize agricultural erosion?

Using chemical fertilizers

Re-planting vegetation (correct)

Intensive ploughing

Maximizing land clearing

What must Australian construction sites implement to meet legal requirements regarding sediment control?

Effective temporary silt traps Signup and view all the answers

How can native vegetation cover contribute to the environment during development?

It provides wildlife corridors Signup and view all the answers

What defines an ecosystem?

A community of interacting organisms and their physical environment Signup and view all the answers

Which of the following is an abiotic factor affecting terrestrial environments?

Soil quality Signup and view all the answers

What is the role of producers in an ecosystem?

They convert sunlight or chemicals into energy Signup and view all the answers

How do predator numbers typically change in relation to prey populations?

They follow the fluctuations of prey populations Signup and view all the answers

Which factor is least likely to affect predator-prey relationships?

Color of prey species Signup and view all the answers

What typically happens to the populations of predators in a large community?

They fluctuate over time in response to prey numbers Signup and view all the answers

In an ecosystem, what is the function of decomposers?

To break down dead organisms into reusable forms Signup and view all the answers

What is biotic factor NOT typically associated with?

Chemical composition of soil Signup and view all the answers

What primarily contributed to the extinction of large Australian animals in the last 100,000 years?

Changes in climate and arrival of humans Signup and view all the answers

Which of the following is NOT a reason proposed for the extinction of megafauna in Australia?

Increased competition among large animals Signup and view all the answers

How did the Aboriginal rock paintings provide evidence of past ecosystems?

They depicted extinct species and climatic changes Signup and view all the answers

What role did ice core drilling play in understanding past climate changes?

It captures gas bubbles that indicate historical atmosphere conditions Signup and view all the answers

Which of the following is a method used for radiometric dating?

Counting decay products of specific radioisotopes Signup and view all the answers

The presence of iron banded formations indicates what about the early Earth's atmosphere?

It was primarily anaerobic Signup and view all the answers

What factor is believed to have caused a peak in megafauna extinction before the last ice age?

Pre-existing ice ages Signup and view all the answers

What is one significant characteristic of the Thylacine?

It resembles a large dog Signup and view all the answers

Which of these statements about the extinction of the Thylacine is true?

It faced habitat loss and competition from introduced species Signup and view all the answers

What does the study of palaeontology primarily focus on?

The fossils of past organisms Signup and view all the answers

What evidence have scientists used to determine changes in historical environments?

Analysis of rock stratigraphy and fossil records Signup and view all the answers

What benefit do air pocket fossils provide for understanding past climate?

They contain information about the atmosphere when the ice formed Signup and view all the answers

Why are changes in the type and number of organisms depicted in Aboriginal paintings significant?

They reflect climatic changes over thousands of years Signup and view all the answers

What term describes competition between members of the same species?

Intraspecific competition Signup and view all the answers

Which of the following is an example of allelopathy?

Pine trees releasing acidic chemicals Signup and view all the answers

What type of symbiotic relationship benefits both organisms involved?

Mutualism Signup and view all the answers

Which type of disease poses the biggest threat to ecosystems?

Infectious diseases Signup and view all the answers

What does the competitive exclusion principle state?

One species will always outcompete another for resources. Signup and view all the answers

In what way can an organism adapt if forced out of its fundamental niche?

By evolving to fill a new realized niche Signup and view all the answers

What is the purpose of using quadrats in ecology?

To measure abundance in plants or immobile animals Signup and view all the answers

Which of the following is an example of commensalism?

An epiphytic plant growing on a tree Signup and view all the answers

What defines an ecological niche?

The role an organism plays in its ecosystem Signup and view all the answers

What is a possible consequence of habitat isolation on disease spread?

Slower disease transmission Signup and view all the answers

Which factor can exacerbate the spread of infectious diseases in a population?

Environmental changes Signup and view all the answers

How does an increasing human population contribute to selection pressures on ecosystems?

By requiring more space for agriculture and habitation. Signup and view all the answers

What is the primary consequence of salinisation on soil fertility?

It decreases soil microbe populations and plant growth. Signup and view all the answers

What role do generalist species play in ecosystems experiencing competition?

They adapt to changes more easily. Signup and view all the answers

Which process can lead to the biomagnification of toxic substances in an ecosystem?

The accumulation of pesticides in soil and water. Signup and view all the answers

Which of the following species was part of Australia's megafauna?

Giant emu-like bird Signup and view all the answers

What distinguishes capture-recapture methods from other sampling techniques?

They are used for highly mobile organisms Signup and view all the answers

What is eutrophication primarily caused by?

Fertilizers washing into rivers and waterways. Signup and view all the answers

How do introduced species typically affect native ecosystems?

They can out-compete native species for resources. Signup and view all the answers

What role do biologists play in predicting future impacts on biodiversity?

They evaluate past extinction events to create predictive models. Signup and view all the answers

What is a major environmental issue stemming from mining activities?

Contamination and alteration of local ecosystems. Signup and view all the answers

Which of the following is an effect of human-induced climate change on ecosystems?

Increased frequency of extreme weather events. Signup and view all the answers

Which factor contributes to the disruption of ecological relationships?

The introduction of invasive species. Signup and view all the answers

What can excessive use of pesticides lead to in an ecosystem?

Loss of both targeted and non-target species. Signup and view all the answers

What happens to water levels due to land clearing for agriculture?

They rise to the surface, increasing soil moisture. Signup and view all the answers

How does increased salinity affect organisms in an ecosystem?

It causes critical damage to cells and tissues. Signup and view all the answers

What is the result of cleared land leading to habitat fragmentation?

Higher competition for limited resources. Signup and view all the answers

What challenge do biologists face when studying the effects of climate change on ecosystems?

Isolating climate effects from other environmental factors. Signup and view all the answers

What are the consequences of increased efficiency in food production on ecosystems?

It can drive overpopulation and resource exploitation. Signup and view all the answers

Study Notes

Biosphere and Ecosystems

The biosphere encompasses all living organisms and their interactions with both biotic (living) and abiotic (non-living) factors.
Ecosystems are formed by communities of interacting organisms and their environments, influenced by abiotic elements like light, temperature, and soil quality.

Abiotic Factors

Key abiotic components in terrestrial environments: light availability, temperature, rainfall, soil quality, climate, and geology.
In aquatic environments, important factors include depth, salinity, dissolved oxygen, and pressure.

Biotic Factors

Biotic factors include interactions among living organisms across various trophic levels: producers (plants), consumers (animals), and decomposers (fungi and microbes).
Predator-prey dynamics heavily influence population sizes; predator numbers typically follow patterns of prey abundance.

Competition

Competition occurs when organisms vie for limited resources such as food or space, either within the same species (intraspecific) or among different species (interspecific).
Plants exhibit competition through allelopathy, where certain species release chemicals to inhibit growth of nearby individuals.

Symbiosis

Symbiotic relationships enhance biodiversity and ecosystem resilience. Types include:
- Mutualism: both species benefit.
- Commensalism: one species benefits, the other is unaffected.
- Parasitism: one species benefits at the other's expense.

Disease Impact

Diseases can adversely affect populations, with infectious diseases being the most significant threat in ecosystems.
Changes like habitat destruction and overcrowding can facilitate disease spread, as seen in the case of the Devil Facial Tumour Disease affecting Tasmanian devils.

Ecological Niches

Ecological niches define an organism's role within its ecosystem, considering both its physical space and functional interactions.
The competitive exclusion principle states that no two species can occupy the same niche simultaneously without one being outcompeted.

Population Sampling Techniques

Sampling methods like quadrats, transects, and capture-recapture help estimate species distribution and abundance when direct counting is impractical due to the organism's behavior or habitat size.

Extinction Events

Examples include the extinction of Australian Megafauna around 40,000 years ago, likely due to climatic changes and human arrival.
The Tasmanian tiger (Thylacine) went extinct in 1936 due to human impacts such as habitat loss and introduced predators.

Palaeontological and Geological Evidence

Fossils and rock formations provide insights into historical ecosystems and climate changes, such as the difference in atmospheric oxygen levels over time.
Aboriginal rock paintings offer a historical record of past biotic interactions and environmental conditions.

Future Ecosystem Management

Human activities, including overpopulation and resource exploitation, impose selection pressures that can threaten biodiversity.
Key issues include land clearing, salinisation, pesticide use, eutrophication, and introductions of non-native species, all impacting ecosystem balance.

Climate Change Impacts

Ongoing climate change is linked to increased carbon dioxide levels from fossil fuel consumption, resulting in rising global temperatures.
Climate change causes stresses such as hotter temperatures, sea level rise, and more frequent extreme weather events.

Mining and Environmental Practices

Mining activities degrade ecosystems and alter land chemistry. Current legislation mandates rehabilitation efforts post-mining to restore environmental integrity.
Sustainable practices are crucial for future ecosystem management to ensure resilience against ongoing human impacts.### Mining Rehabilitation
Vegetation, seeds, and seedlings should be cleared, stockpiled, and nurtured for later rehabilitation.
Tailings, which are waste products from mining, need proper treatment and management.
Once mining is finished, the pit must be refilled with landfill or water, transforming it into a dam.
Stockpiled soil is then respread, followed by gradual reintroduction of vegetation to support ecosystem recovery.
Successful rehabilitation allows for the return of native animals and plants to the area.

Agriculture and Soil Erosion

Soil is crucial for terrestrial agriculture in Australia, underpinning food production globally.
Traditional farming practices, like ploughing, expose soil to erosion by rain and wind, removing fine particles and essential nutrients.
Techniques to reduce agricultural erosion include:
- Minimizing ploughing by using environmentally safe chemicals to control weeds, preserving topsoil.
- Re-planting vegetation (e.g., trees) to stabilize soil and decrease erosion risks.

Urban Construction and Soil Management

Land clearing in urban settings can contaminate local waterways with excess sediments.
Australian regulations mandate effective temporary silt traps on construction sites to prevent sediment pollution.
Maintaining vegetation cover on road verges, development perimeters, and creek banks helps reduce erosion and provides wildlife corridors.
Native vegetation supports biodiversity while aiding in the rehabilitation of the disturbed land.

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Description

This quiz covers essential concepts about ecosystems, food chains, and the roles of biotic and abiotic factors within the biosphere. Test your understanding of population dynamics and the impact of these interactions on top predators and overall biodiversity. Perfect for biology students looking to solidify their knowledge in ecology.