Topic 9 - Ecosystems and Material Cycles

• What is an individual in Biology?

  A Single organism.
• What is population in Biology?

  All organisms of one species in a habitat.
• What is a community in Biology?

  All organisms of different species living in a habitat.
• What is an eco-system?

  A community of organisms and their physical (abiotic) environment.
• What are the abiotic factors that affect communities?

  Temperature: changes in temperature affects the distribution of species in an area as they might get (un)comfortable.

  Amount of water: A change in water in a community might drastically change the growth of organisms.

  Light intensity: A limiting factor of photosynthesis - it would affect the distribution of plants in a community.

  Levels of pollutants: Organisms may not survive if there is a high concentration of a pollutant in the air.
• What is the importance of independence in a community?

  Biodiversity, Ecological balance, Food chains and Energy flow.
• What is mutualism?


  Mutualism is a type of symbiotic relationship where both organisms benefit. For example, clownfish and sea anemone.
• What is parasitism?


  A symbiotic relationship where one organism benefits at the expense of another. For example, Lice and a dog.
• What are the biotic factors that affect communities?

  Competition: Organisms compete with other species for the same resources.

  Predation: Increasing the number of predators decreases the number of prey.
• How do you use a quadrat to study the distribution with small animals?

  • Select study area
  • Place quadrat randomly
  • Count animals in the quadrat
  • Record species and numbers
  • Repeat in multiple locations
  • Analyze data statistically
  • Conclude distribution
  • Evaluate the method's limitations and improvements.
• How do you used a belt transect and a quadrat to study a distribution along the gradient?

  • Choose study site
  • Use quadrats: count organisms
  • Use belt transects: record along the tape
  • Analyze data statistically
  • Conclude relationship
  • Evaluate methods for improvements.
• Mean = total number of organisms/ total number of quadrats.
• Some energy is transferred to less useful forms at each trophic level. This affects the number of organisms at each trophic level, limits the length of a food chain and determines the shape of a pyramid of biomass in an ecosystem.
• Energy in the food chain can be lost due to preparation homeostasis and lost in waste.
• How do you calculate the efficiency of energy transfer?

  efficiency = energy transferred to the next level/energy available at the previous level.

  
• What are the positives and negatives of fish farming?

  Positives: Increased food production, reduced pressure on wild fish populations. Negatives: Pollution from waste, disease transmission to wild fish.
• What are the positives and negatives of introducing non-indigenous species into a new habitat?

  Positives: Increased biodiversity, pest control. Negatives: Disruption of ecosystem, competition with native species.
• What is Eutrophication?


  Excessive nutrients in a body of water leading to excessive plant growth and oxygen depletion.
• What are the positives and negatives of Eutrophication?

  Positives: Increased plant growth, and higher fish populations. Negatives: Algal blooms, oxygen depletion, fish kills.
• What are some ways of maintaining local and global biodiversity?

  Reforestation: replanting land that used to contain plants to restore habitats and biodiversity.

  protecting endangered species: Protecting species in safe areas and using seed banks to prevent extinction.
• What are the main benefits of biodiversity?

  1. protecting the human food supply
  2. ensuring minimal damage to food chains
  3. Providing future medicines
  4. Eco-tourism
  5. Providing new jobs.
• What are the biological factors affecting levels of food security?

  Increasing human population: Food production must increase to meet the human population's demand.

  Increased consumption of meat and fish: More farming and land are needed to meet the demand.

  Pests and pathogens: can cause damage to crops and livestock which reduces yield.

  Environmental changes caused by human activity: Global warming increases temperature - make some crops harder to grow.

  Sustainability: fossil fuels will eventually run out making food transport a bigger problem.
• How do materials cycle through ecosystems?

  • Abiotic components: Non-living materials cycle (carbon, nitrogen, water).
  • Biotic components: Living organisms interact with materials for life processes.
  • Processes: Photosynthesis, respiration, and decomposition drive cycling.
  • Human impact: Activities disrupt cycles, leading to degradation.
  • Importance: Conservation and sustainability are crucial for ecosystem health.
• What is the importance of the carbon cycle?

  The carbon cycle is crucial for climate regulation, oxygen production, ecosystem balance, biodiversity support, and understanding human activity impacts.
• What are the main stages of the carbon cycle?

  • Photosynthesis: Plants absorb CO2, produce glucose, release O2.
  • Respiration: Plants, and animals release CO2 through metabolism.
  • Decomposition: Decomposers break down matter, and release CO2.
  • Combustion: Burning releases CO2 from fossil fuels, and biomass.
  • Diffusion and Dissolution: CO2 dissolves in water, used by aquatic life.
  • Sedimentation: Burial of organic matter forms fossil fuels.
  • Weathering: Release of carbon from rocks into soil, and water.
  • Fossilization: Organic matter becomes fossilized, forming rocks.

  
• What is the importance of the water cycle?

  • Essential for providing freshwater for drinking, agriculture, and industry.
  • Regulates Earth's climate by transporting heat around the globe.
  • Supports ecosystems by providing water for plants and animals.
• What are the stages of the water cycle?

  • Evaporation: Water heats, turns to vapour, and ses.
  • Condensation: Vapor cools, and forms clouds.
  • Precipitation: Clouds release water as rain or snow.
  • Infiltration/Percolation: Water seeps into soil, and groundwater.
  • Runoff: Excess water flows over land into rivers and oceans.
  • Transpiration: Plants release water vapour through leaves.
  • Surface Evaporation: Surface water evaporates into vapour.

  
• What is the role of the nitrogen cycle?

  • Converts atmospheric nitrogen into forms usable by living organisms.
  • Essential for the synthesis of proteins, DNA, and other biomolecules.
  • Facilitates nitrogen fixation, nitrification, assimilation, and denitrification processes.
• What are the stages of the nitrogen cycle?

  • Nitrogen Fixation: Bacteria convert N2 to NH4+ or NO3-.
  • Nitrification: NH4+ converted to NO2-, then to NO3-.
  • Assimilation: Plants absorb NO3- for organic compounds.
  • Ammonification: Decomposers release NH4+ from organic matter.
  • Denitrification: Bacteria convert NO3- to N2 or N2O.
  • The cycle repeats, maintaining nitrogen balance in ecosystems.

  
• What are the 4 different types of bacteria and their uses in the nitrogen cycle?

  • Decomposers: Break down proteins, urea into ammonia.
  • Ammonia: Converted to ammonium ions for plant use.
  • Nitrifying Bacteria: Convert ammonia to nitrites, then nitrates.
  • Nitrogen Fixers: Turn atmospheric N2 into ammonia, then ammonium ions.
  • Denitrifying Bacteria: Convert nitrates to N2 gas, no benefit to organisms often found in waterlogged soils.
• What are indicator species?

  Species sensitive to environmental changes.
• What are examples of indicator species?

  • Butterflies: Habitat quality indicators.
  • Birds: Reflect habitat and climate changes.
• What indicator species are found and not found in water pollution?

  Found: blood worms and sludge worms. Not found: Mosquito and larvae.
• What indicator species suffer from air pollution?

  Lichens - can't grow due to a large presence of sulfur dioxide.

  Black spot fungi - cannot grow without the presence of clean air.
• What factors affect the rate of decomposition?

  Temperature, water content and oxygen availability.
• How does temperature speed up the rate of decomposition?

  a warm temperature speeds up the rate of enzyme-controlled reactions in the microbes. Enzymes will denature if the temperature gets too high.
• How does water content affect the rate of decomposition?

  Decays take place faster in moist environments because the organisms involved in decay need water to survive and carry out biological processes.
• How does oxygen availability affect the rate of decomposition?

  Many of the microorganisms responsible for the decomposition rate require oxygen to carry out aerobic respiration.
• How do you reduce or stop the rate of decomposition?

  • Refrigeration/freezing: Lowers temperature, slows or stops decomposers.
  • Airtight cans: Prevent microorganism entry, sterilized to kill existing microbes.
  • Drying: Removes water, and deprives microorganisms of needed moisture.
  • Salt/sugar: Causes microorganisms to lose water through osmosis.
• How do you calculate rate changes in the decay of biological material?

  divide the number of moulds by the number of days in the given data.