Ecosystems: Interactions and Impacts

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Questions and Answers

Describe how combustion impacts nutrient cycling within an ecosystem.

Combustion releases stored nutrients (e.g., carbon) into the atmosphere as gases, altering the nutrient balance and availability within the ecosystem.

Explain the difference between a food chain and a food web, and why food webs are more representative of real ecosystems.

A food chain shows a single, linear pathway of energy transfer, while a food web consists of interconnected food chains. Food webs better represent ecosystems due to the complex, varied diets of most organisms.

A certain plant species experiences increased herbivory from insects. Describe a potential defense mechanism, and how this adaptation helps the plant population persist.

The plant might develop chemical defenses (e.g., producing toxins) that deter the insects. This reduces herbivory, allowing the plant to grow, reproduce, and maintain its population.

Describe how decomposers contribute to the health of an ecosystem.

Decomposers break down dead organic matter, releasing nutrients back into the environment. These nutrients are then available for producers, fueling the food web and supporting plant growth. They also reduce the risk of disease. Signup and view all the answers

Explain how a change in an abiotic factor, such as increased rainfall, could affect a local population of herbivores.

Increased rainfall could lead to greater plant growth, providing more food for the herbivores. This could increase the herbivore population size due to increased food availability and subsequent reproduction rates. It may also bring in new predators. Signup and view all the answers

Describe the difference between commensalism and mutualism.

Commensalism is a relationship where one species benefits and the other is unaffected, while mutualism is a relationship where both species benefit. Signup and view all the answers

A new housing development clears a large area of forest. Describe two potential impacts of this habitat destruction on the local ecosystem.

Habitat loss can lead to a decrease in biodiversity as species lose their homes and sources of food. It can also lead to increased competition for resources among the remaining organisms, and potential fragmentation of populations. Signup and view all the answers

Explain the concept of a niche. Why is it important for an organism to have its own niche within it's ecosystem?

A niche is an organism's role in an ecosystem, including its habitat, food sources, and interactions with other species. Having a distinct niche reduces competition and allows species to coexist by utilizing different resources or playing different roles. Signup and view all the answers

Compare and contrast the roles of autotrophs and heterotrophs in an ecosystem. How does each group contribute to the flow of energy and matter?

Autotrophs produce their own food using energy from sunlight or chemical sources, forming the base of the energy pyramid. Heterotrophs consume other organisms for energy, transferring energy and nutrients through the food web. Autotrophs create, heterotrophs consume. Signup and view all the answers

Explain how the concept of a 'niche' differs from that of a 'habitat'. Provide an example to illustrate your explanation.

A habitat is the physical environment where an organism lives, while a niche is the organism’s role and function within that environment, including its interactions with other species and resources. For example, a tree is the habitat for many birds, but each bird species has a different niche depending on what it eats, where it nests, and how it interacts with other organisms. Signup and view all the answers

Describe a specific example of mutualism and explain how each species benefits from the interaction.

An example of mutualism is the relationship between bees and flowering plants. Bees benefit by obtaining nectar for food, while the plants benefit from the bees' pollination, which aids in their reproduction. Signup and view all the answers

Outline the main processes involved in the carbon cycle, explaining how carbon moves between living organisms and the atmosphere.

The carbon cycle involves photosynthesis, where plants absorb carbon dioxide from the atmosphere; respiration, where organisms release carbon dioxide back into the atmosphere; consumption, where carbon is transferred through food chains as organisms eat each other; decomposition, where carbon is released back into the environment from dead organisms; and combustion, where burning organic material releases carbon into the atmosphere. Signup and view all the answers

Explain how deforestation contributes to climate change. Be sure to include the impact on the carbon cycle.

Deforestation reduces the number of trees available to absorb carbon dioxide from the atmosphere through photosynthesis, leading to an increase in atmospheric carbon dioxide concentrations. Additionally, burning the cut trees releases stored carbon into the atmosphere, further exacerbating climate change. Signup and view all the answers

Describe the process of eutrophication and its effects on aquatic ecosystems.

Eutrophication is the enrichment of a body of water with nutrients, often due to runoff from fertilizers or sewage. This leads to excessive algae growth, which, upon dying and decomposing, depletes oxygen levels in the water, harming or killing aquatic life. Signup and view all the answers

Define 'biodiversity' and explain why it is important for the health and stability of ecosystems.

Biodiversity is the variety of life in a particular habitat or ecosystem. It is important because it enhances ecosystem stability, resilience to environmental changes, and provides essential ecosystem services such as pollination, nutrient cycling, and disease regulation. Signup and view all the answers

Discuss the role of national packs and reserves in conserving biodiversity and protecting vulnerable ecosystems.

National parks and reserves protect biodiversity by preserving habitats, preventing habitat destruction and overexploitation of species, and providing areas for scientific research and education about conservation. They also maintain ecosystem functions, preserve genetic diversity, and serve as a refuge for endangered species. Signup and view all the answers

Explain the relationship between barnacles and whales, and identify the type of symbiotic relationship it represents.

Barnacles attach to whales and gain a habitat, while the whales are unaffected. This is an example of commensalism. Signup and view all the answers

Describe how mistletoe growing on a Pohutukawa tree exemplifies parasitism, and explain the consequences for each organism.

The mistletoe benefits by extracting nutrients and water from the Pohutukawa tree, while the Pohutukawa tree is harmed due to the loss of these resources. This is a parasitic relationship. Signup and view all the answers

How have traditional farming methods differed from modern intensive farming, and what are some ecological consequences of this shift?

Traditional farming involved a diverse range of plants and animals, while modern intensive farming focuses on single crops. This shift has led to habitat destruction, pollution, and a reduction in wildlife due to increased use of fertilizers, herbicides, and pesticides. Signup and view all the answers

Outline the role of photosynthesis and respiration in the carbon cycle, explaining how carbon moves between living organisms and the atmosphere.

During photosynthesis, plants absorb carbon dioxide from the atmosphere to produce glucose. During respiration, organisms break down glucose into carbon dioxide and water, releasing carbon dioxide back into the atmosphere. Signup and view all the answers

Describe how the carbon cycle involves decomposition and fossilisation, and how these processes affect the availability of carbon in an ecosystem.

Decomposition breaks down dead organisms and waste, releasing stored carbon into the environment to be used by producers. Fossilisation traps and compresses carbon in dead organisms, forming fossil fuels. Signup and view all the answers

Explain the process of combustion and its impact on the carbon cycle, including how it affects the amount of carbon dioxide in the atmosphere.

Combustion is the burning of fuels like wood, coal, or petrol, which releases carbon dioxide into the atmosphere, increasing the amount of carbon dioxide in the atmosphere. Signup and view all the answers

Prior to intensive agriculture, how did human food-gathering activities impact the environment compared to modern practices?

Early humans obtaining food by hunting and gathering had a smaller impact on the environment, whereas modern intensive farming has resulted in habitat destruction and pollution. This change has led to an increase in the use of fertilizers, herbicides and pesticides to increase the yield of crops. Signup and view all the answers

Describe the importance of the carbon cycle to living things.

Carbon is found in living organisms. Both plants and animals rely on the carbon cycle to survive. Signup and view all the answers

In the provided New Zealand food web, explain how the Stoat and the Tui occupy different trophic levels? Give an example for each.

The Stoat occupies the tertiary/3rd trophic level by consuming Kereru, while the Tui is at the primary/2nd trophic level when it eats Kowhai nectar. Additionally, Tui can occasionally reach the secondary/3rd trophic level when consuming invertebrates. Signup and view all the answers

Explain why food chains rarely exceed five trophic levels, referencing the concept of energy transfer between levels.

Due to the 10% rule of energy transfer, only a small fraction of energy is available at each successive trophic level. After four or five transfers, the energy remaining is insufficient to support another level. Signup and view all the answers

Contrast the feeding strategies and trophic levels of a Kereru and a Stoat in the given New Zealand food web.

A Kereru is a primary consumer (herbivore) that feeds on plants like Tawa, occupying the second trophic level. A Stoat is a secondary consumer (carnivore) that preys on animals like Kereru, occupying the third trophic level. Signup and view all the answers

Describe the role of 'invertebrates' in the New Zealand food web and predict the impact of a significant decline in their population.

Invertebrates serve as a food source for various consumers like Tui, Kiwi, and Rat, connecting primary producers to higher trophic levels. A decline would negatively impact these consumers, potentially leading to population declines or shifts in diet. Signup and view all the answers

Define the term 'food web' and explain why it is a more accurate representation of energy flow in an ecosystem than a 'food chain'.

A food web is a network of interconnected food chains that depicts the complex feeding relationships within a community. It's more accurate than a food chain because most organisms consume multiple food sources and occupy different trophic levels. Signup and view all the answers

Using the examples provided, differentiate between mutualism and commensalism.

Mutualism is a relationship where both species benefit, like Tui pollinating mistletoe while feeding on its nectar. Commensalism benefits one species while neither harming nor helping the other, as barnacles growing on whales. Signup and view all the answers

Identify the autotrophs and heterotrophs in the Tawa-Kereru-Stoat food chain and outline their respective roles in the flow of energy.

Tawa is an autotroph (producer) that converts sunlight into energy. Kereru and Stoat are heterotrophs (consumers), with the Kereru obtaining energy by consuming Tawa and the Stoat obtaining energy by consuming Kereru. Signup and view all the answers

Explain one possible consequence to the miro population if the kereru population was reduced, referencing the food web.

With less kereru, there may be reduced seed dispersal, leading to a possible decline in the miro population due to less seeds being available. Signup and view all the answers

Explain how the development of agriculture allowed humans to form larger groups.

Agriculture allowed humans to produce more food in a given area, exceeding what could be obtained through hunting and gathering in the same area, thus allowing for increased population density. Signup and view all the answers

Describe two ways in which humans alter ecosystems to support agriculture.

Humans clear forests and woodlands to create farmland and they replace diverse plant communities with single crop species. Signup and view all the answers

List three reasons ecosystems are destroyed.

Ecosystems are being destroyed due to increased area needed for food crop growth/livestock production/housing, extraction of natural resources (over harvesting), and pollution/climate change. Signup and view all the answers

Explain how deforestation results in a buildup of carbon dioxide in the atmosphere.

Deforestation reduces the number of trees available to absorb carbon dioxide through photosynthesis. Also, burning trees releases stored carbon into the atmosphere. Signup and view all the answers

Define the term 'pollutant' and give an example.

A pollutant is any substance that contaminates the environment. Examples include sewage water, harmful chemicals, and gases. Signup and view all the answers

Describe the process of eutrophication.

Eutrophication is when excessive nutrients in a body of water causes increased plant growth, which then dies and is broken down by oxygen-consuming bacteria, leading to a drop in oxygen levels and the death of aquatic organisms. Signup and view all the answers

Identify the main causes of eutrophication in New Zealand.

The agriculture, meat, and dairy processing industries are the main causes of eutrophication in New Zealand. Signup and view all the answers

How do humans alter food webs?

Humans alter food webs by changing the species present in an area, such as deforestation which impacts habitation ultimately altering the food available. Signup and view all the answers

Explain why raw materials like metal ores are considered non-renewable resources.

Metal ores are considered non-renewable because they are formed over extremely long geological timescales, and their rate of formation is much slower than the rate at which humans extract and use them. Therefore, they will eventually run out. Signup and view all the answers

Describe how traditional approaches to food collection, such as restrictions on Kina collection, contribute to sustainability.

Restrictions on food collection ensure that the population can replenish itself. By limiting the amount harvested, there will be enough for future years, ensuring the practice is sustainable. Signup and view all the answers

Explain why a rainforest is considered to have higher biodiversity than a field of wheat.

A rainforest contains millions of different species of plants, animals, and microorganisms, each contributing to the ecosystem's complexity. A field of wheat has very low biodiversity as it contains primarily one species. Signup and view all the answers

What are the three main rationales scientists use to explain why maintaining biodiversity is important?

The three main categories are: biodiversity required for human use (medicinal, food, genetic reasons), biodiversity to maintain nature (keystone species), and ethical considerations. Signup and view all the answers

Describe the connection between biodiversity and food security and how a changing climate might impact this relationship.

Currently, a small number of organisms provide majority of the world's food supply. Climate change may affect the yield of these crops meaning humans will have to find new sources of food from other organisms, so maintaining biodiversity ensures more species are available should current food sources fail. Signup and view all the answers

What is a keystone species, and why is its role significant in an ecosystem?

A keystone species is a species that plays a critical role in maintaining the structure, function, and stability of an ecosystem. Without it, the dynamics of the ecosystem change drastically, often leading to its collapse. Signup and view all the answers

Explain how overfishing of Snapper can lead to an increase in the Kina population, and why this is an ecological concern.

Snapper eat Kina, so overfishing of Snapper removes the predatory pressure on the Kina population. This allows the Kina population to increase rapidly. An overabundance of Kina can lead to overgrazing of kelp forests and other marine habitats, which can severely damage these ecosystems. Signup and view all the answers

In what scenario might genetic resources from wild relatives of major food crops become essential for ensuring food security?

If a major food crop becomes susceptible to a disease, genes conferring immunity from closely related wild organisms may need to be used to provide immunity to that disease. Signup and view all the answers

Flashcards

Species

A group of organisms that can interbreed and produce fertile offspring.

Ecosystem

A community of interacting organisms and their physical environment.

Niche

The role an organism plays in its environment, including its interactions with biotic and abiotic factors.