ecology + cycles

• What is the main topic of the video?

  Energy transfer and productivity
• What should new viewers do to stay updated?

  Click subscribe
• How is energy transferred in an ecosystem?

  Through a food web
• Who are the producers in an ecosystem?

  Plants
• What do producers create using carbon dioxide and water?

  Carbohydrates or organic matter
• What is lost between each trophic level?

  Energy
• What are two ways energy is lost in an ecosystem?

  Respiration and excretion
• What is biomass in an ecosystem?

  Energy available to the next trophic level
• How can biomass be measured?

  Mass of carbon or dry mass of tissue
• How do you calculate the biomass of a plant?

  Remove all water to get dry mass
• What do GPP and NPP stand for?

  Gross primary productivity and net primary productivity
• What does GPP measure?

  Total energy from photosynthesis
• How is NPP calculated?

  GPP minus energy lost in respiration
• Why is NPP important?

  It indicates energy available for new biomass
• How does a rainforest compare to a desert in terms of productivity?

  Rainforest has higher GPP and NPP
• What is the formula for net production of consumers?

  Energy ingested minus energy lost
• What additional components are considered for consumers compared to plants?

  Energy lost in feces and urine
• What units are used to measure productivity?

  Kilojoules per hectare per year
• Why do we use per hectare in productivity calculations?

  To standardize results for fair comparison
• Why is productivity measured per year?

  To account for variations throughout the year
• What are the key concepts of energy transfer and productivity in ecosystems?

  • Energy is transferred through food webs.
  • Producers (plants) create carbohydrates.
  • Energy is lost at each trophic level.
  • Biomass is the energy available for the next level.
  • GPP measures total energy from photosynthesis.
  • NPP measures energy available for new biomass.
• What factors influence the productivity of an ecosystem?

  • Abiotic factors: water, light intensity, temperature
  • Biotic factors: presence of green plants
  • Higher productivity with favorable conditions
• What is the significance of measuring NPP in ecosystems?

  • Indicates energy available for new biomass
  • Essential for understanding ecosystem productivity
  • Helps compare different ecosystems
• Who is the presenter of the nitrogen cycle video?

  Miss Esther
• Why is the nitrogen cycle important?

  It helps convert nitrogen gas for plants and animals
• What percentage of the atmosphere is nitrogen gas?

  30 percent
• Why can't animals and plants obtain nitrogen through gas exchange?

  Nitrogen gas has a triple bond, making it inert
• What do microorganisms do in the nitrogen cycle?

  They break nitrogen gas bonds to convert it
• How do plants absorb nitrogen-containing substances?

  Through active transport in their roots
• What biological molecules contain nitrogen?

  Proteins, amino acids, ATP, nucleic acids
• What are the four key processes of the nitrogen cycle?

  • Ammonification
  • Nitrification
  • Nitrogen-fixing
  • Denitrification
• What is ammonification in the nitrogen cycle?

  It is the creation of ammonium from organic matter
• What is nitrification?

  It is the conversion of ammonium to nitrates
• What is nitrogen-fixing?

  Converting nitrogen gas into nitrogen-containing compounds
• Where does nitrogen-fixing occur in plants?

  In root nodules
• Which plants typically have root nodules for nitrogen-fixing?

  Leguminous plants
• What do nitrogen-fixing bacteria convert nitrogen gas into?

  Ammonium or nitrates
• What is the role of nitrifying bacteria in the soil?

  They convert ammonium into nitrites and nitrates
• What happens to nitrates in the soil?

  They are absorbed by plants through active transport
• What do plants use nitrates for?

  To create amino acids, ATP, and DNA