unit 20 - human influence on ecosystems

How do agricultural machinery increase food production?

Agricultural machinery, such as tractors, plows, and harvesters, allow farmers to cultivate larger areas of land more efficiently, increasing productivity and reducing labor time.

What is a disadvantage of using agricultural machinery?

Heavy machinery can cause soil compaction, which reduces water drainage and lowers soil fertility.

How do chemical fertilizers increase food production?

Chemical fertilizers provide essential nutrients (such as nitrogen, phosphorus, and potassium) to crops, leading to increased yields.

What is a disadvantage of using chemical fertilizers?

Overuse of fertilizers can cause eutrophication, which leads to algae blooms and oxygen depletion in water bodies.

How do insecticides increase food production?

Insecticides are used to kill pests that feed on crops, reducing crop damage and increasing yield.

What is a disadvantage of using insecticides?

Insecticides can harm beneficial insects like pollinators and lead to the development of insecticide

How do herbicides increase food production?

Herbicides kill weeds that compete with crops for light, nutrients, and water, allowing crops to grow more efficiently.

What is a disadvantage of using herbicides?

Some herbicides persist in the environment for a long time, potentially contaminating water sources.

How does selective breeding increase food production?

Selective breeding involves choosing organisms with desirable traits (e.g., high yield, disease resistance) to improve future generations of crops and livestock.

What is a disadvantage of selective breeding?

Selective breeding reduces genetic diversity, making crops and animals more vulnerable to diseases.

What is a monoculture?

A monoculture is the cultivation of a single crop type over a large area.

What is an advantage of large scale monocultures?

Monocultures allow efficient farming, as specialized machinery can be used for planting and harvesting, increasing crop yields.

What is another advantage of large scale monocultures?

Monocultures simplify pest and weed control, as specific insecticides and herbicides can be applied to one crop type.

What is a disadvantage of large scale monocultures?

Monocultures deplete soil nutrients, as the same crop is grown repeatedly, reducing soil fertility.

What is another disadvantage of large scale monocultures?

The lack of genetic diversity in monocultures increases the risk of pests and diseases wiping out entire crops.

What is another disadvantage of large scale monocultures?

Large-scale monocultures rely heavily on chemical inputs such as fertilizers, insecticides, and herbicides, which can harm the environment.

What is intensive livestock production?

Intensive livestock production involves keeping large numbers of animals in confined spaces to maximize meat, milk, and egg production.

What is an advantage of intensive livestock production?

Intensive livestock farming allows for higher efficiency and food production in less space.

What is another advantage of intensive livestock production?

Intensive livestock production reduces the cost of meat and dairy products, making food more affordable.

What is another advantage of intensive livestock production?

Controlled conditions in intensive farming allow farmers to regulate feeding, breeding, and health, leading to improved yields.

What is a disadvantage of intensive livestock production?

Animals are often kept in crowded conditions, limiting movement and natural behaviors, leading to animal welfare concerns.

What is another disadvantage of intensive livestock production?

Intensive livestock production increases the risk of diseases spreading rapidly due to close confinement, requiring the use of antibiotics.

What is another disadvantage of intensive livestock production?

Intensive livestock production generates large amounts of waste, which can pollute water sources and contribute to greenhouse gas emissions.

What is biodiversity?

Biodiversity refers to the variety of living organisms in a given area, including different species of animals, plants, fungi, and microorganisms.

Why is high biodiversity important?

High biodiversity is essential for ecosystem stability, providing resources such as food, medicine, and oxygen.

How do human activities impact biodiversity?

Human activities that destroy habitats lead to a loss of biodiversity, negatively impacting ecosystems.

What is the cause of habitat destruction?

Habitat destruction is primarily caused by human activities, leading to the loss of ecosystems and species.

How does expanding areas for housing contribute to habitat destruction?

Expanding cities and towns require deforestation and land clearing, leading to habitat loss.

How does large scale monoculture farming contribute to habitat destruction?

Large-scale monoculture farming removes natural habitats, leading to biodiversity loss.

How does livestock farming contribute to habitat destruction?

Livestock farming requires vast areas of land, contributing to deforestation and biodiversity loss.

How does the extraction of natural resources cause habitat destruction?

Mining destroys land and pollutes nearby water sources, while oil drilling can lead to oil spills, damaging marine ecosystems.

How does deforestation for timber contribute to habitat destruction?

Deforestation for timber reduces tree cover, leading to soil erosion and loss of animal habitats.

What impact does freshwater and marine pollution have on habitats?

Industrial waste, sewage, and agricultural fertilizers and pesticides pollute water bodies, while plastic pollution harms marine life.

How do oil spills impact marine ecosystems?

Oil spills coat marine organisms, disrupting their ability to breathe and move.

How does habitat destruction impact food webs and food chains?

Habitat destruction can break food chains, leading to imbalances in ecosystems and loss of species.

What happens to predators when habitat destruction breaks food chains?

Predators may lose prey, forcing them to migrate or die out.

How does loss of plant species impact food webs?

Loss of plant species reduces food sources for herbivores, affecting the entire food web.

How do foreign species affect food webs?

The introduction of foreign species due to habitat destruction can lead to competition with native species, sometimes leading to extinctions.

What is deforestation?

Deforestation is the clearing of forests for agriculture, urban development, or logging.

How does deforestation reduce biodiversity?

Deforestation destroys habitats that support a wide range of plant and animal species, leading to species extinction.

What is the impact of deforestation on extinction?

Animals and plants that rely on forests may die out if they cannot adapt, with species that have specialised habitats being most at risk.

How does deforestation lead to soil loss?

Trees help hold soil in place with their roots; without tree cover, soil erosion increases, leading to desertification.

How does deforestation contribute to flooding?

Trees absorb excess rainwater; without forests, rainwater runs off quickly, causing floods in nearby areas.

How does deforestation increase carbon dioxide levels?

Trees absorb CO₂ through photosynthesis; deforestation reduces this carbon absorption, contributing to global warming. Burning or decaying trees releases stored carbon, further increasing CO₂ levels.

What are the effects of untreated sewage on aquatic ecosystems?

Untreated sewage contains harmful bacteria and viruses, leading to diseases like cholera and typhoid. Organic waste is broken down by decomposers, using up oxygen and depleting oxygen levels, causing the death of aquatic organisms.

How does excess fertiliser affect aquatic ecosystems?

Excess fertilisers contain nitrates and phosphates that leach into water bodies, causing eutrophication, algal blooms, and oxygen depletion, resulting in the death of aquatic organisms.

What is eutrophication?

Eutrophication is the excessive growth of algae in water bodies due to nutrient runoff from fertilisers and sewage, leading to oxygen depletion and the death of aquatic organisms.

What are the steps in the process of eutrophication?

Increased availability of nitrate and other ions, rapid growth of producers, algae blocking sunlight, death of producers, decomposers breaking down dead organisms using aerobic respiration, oxygen depletion, and death of aquatic animals due to lack of oxygen.

How do non biodegradable plastics affect aquatic ecosystems?

Plastic waste pollutes oceans, rivers, and lakes, harming marine animals through ingestion and entanglement. Microplastics enter the food chain, affecting marine life and human health.

How do non biodegradable plastics affect terrestrial ecosystems?

Plastics accumulate in landfills, leaching harmful chemicals into the soil and contaminating groundwater. Animals ingest plastic, leading to starvation and death

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What are the sources of carbon dioxide (CO₂) pollution?

Carbon dioxide is released by burning fossil fuels (coal, oil, gas) and deforestation, which reduces the number of trees that absorb CO₂.

What are the effects of carbon dioxide on the environment?

CO₂ contributes to the enhanced greenhouse effect, trapping heat in the atmosphere, leading to global warming, climate change, and rising sea levels.

What are the sources of methane (CH₄) pollution?

Methane is released from livestock farming (during digestion), decomposing organic waste in landfills, and the extraction of natural gas.

What are the effects of methane on the environment?

Methane is more potent than CO₂ in trapping heat, worsening the greenhouse effect and contributing to climate change by raising global temperatures.

What is the enhanced greenhouse effect?

The enhanced greenhouse effect occurs when increased levels of greenhouse gases like CO₂ and CH₄ trap more heat in the Earth's atmosphere, causing global warming.

How does the enhanced greenhouse effect contribute to climate change?

The enhanced greenhouse effect leads to rising global temperatures, melting polar ice caps, rising sea levels, extreme weather events, and disruption of ecosystems.

What are the consequences of climate change?

Climate change causes rising global temperatures, extreme weather events, melting polar ice caps, rising sea levels, and species extinction due to ecosystem disruption.

What is a sustainable resource?

A sustainable resource is one that is produced as rapidly as it is removed from the environment, ensuring it does not run out.

What are examples of sustainable resources?

Forests (if replanted after logging) and fish stocks (if overfishing is avoided and breeding populations are maintained).

How can forests be conserved?

Through education, protected areas, quotas, and replanting efforts.

How can fish stocks be conserved?

Through education, closed seasons, protected areas, controlled net types and mesh size, quotas, and monitoring.

What are the causes of species becoming endangered or extinct?

Climate change, habitat destruction, hunting, overharvesting, pollution, and introduced species.

How can endangered species be conserved?

Through monitoring and protecting species and habitats, education, captive breeding programmes, and seed banks.

What is the importance of conservation programmes?

To maintain or increase biodiversity, reduce extinction, protect vulnerable ecosystems, and maintain ecosystem functions like nutrient cycling and resource provision.

How can forests be conserved using education?

By raising awareness of the importance of forests and sustainable practices.

How can forests be conserved using protected areas?

By establishing national parks and reserves where logging is prohibited.

What are quotas in forest conservation?

Limiting the number of trees that can be cut down to prevent overharvesting.

How can fish stocks be conserved using closed seasons?

By banning fishing during breeding seasons to allow populations to recover.

How can fish stocks be conserved using protected areas?

By creating marine reserves where fishing is restricted to protect fish populations.

What is the role of controlled net types and mesh size in fish stock conservation?

Ensuring that small fish can escape to grow and reproduce, maintaining fish populations.

What is the role of monitoring in fish stock conservation?

Using satellite tracking and patrols to enforce fishing regulations and prevent overfishing.

What is the effect of climate change on species endangerment?

Climate change disrupts food sources and habitats, leading to species being endangered or extinct.

How does habitat destruction contribute to species endangerment?

Deforestation, urbanisation, and pollution destroy natural habitats, leaving species without shelter or food.

How does hunting contribute to species endangerment?

Overhunting and poaching drastically reduce populations, pushing species toward extinction.

What is overharvesting and how does it contribute to species endangerment?

Overharvesting, like overfishing and deforestation, depletes resources faster than they can be replenished.

How does pollution lead to species endangerment?

Pollution from oil spills, pesticides, and plastics harms wildlife and disrupts ecosystems.

How do introduced species contribute to species endangerment?

Introduced species outcompete native species for resources, leading to population declines.

What is the role of education in conserving endangered species?

Education raises awareness about endangered species and promotes conservation efforts.

How does captive breeding help conserve endangered species?

Captive breeding programmes breed endangered species in captivity to increase their population size.

What are seed banks?

Seed banks store seeds from endangered plants to preserve biodiversity and ensure their survival.

What are the goals of conservation programmes?

To maintain or increase biodiversity, reduce extinction, protect vulnerable ecosystems, and maintain ecosystem functions.

What is the role of nutrient cycling in ecosystem conservation?

Nutrient cycling helps maintain soil fertility and supports plant and animal life in ecosystems.

What resources do conservation programmes aim to protect?

Food, medicine, fuel, and genetic diversity for breeding.

How does artificial insemination (AI) help in captive breeding?

AI involves collecting sperm from a male and inserting it into a female without mating, increasing genetic diversity.

How does in vitro fertilisation (IVF) help in captive breeding?

IVF fertilises eggs outside the body and implants embryos into females, aiding the breeding of endangered species.

Why is genetic diversity important for species survival?

It helps species adapt to environmental changes and resist diseases, improving their chances of survival.

What are the risks of reduced genetic variation in species?

Reduced genetic variation increases the risk of diseases, genetic disorders, and reduces the species' ability to adapt to environmental changes.