T5: On the wild side

• What is an ecosystem?

  All the organisms living in a particular area and all the nonliving elements of that environment.
• What is a community in ecological terms?

  All of the populations of all the organisms living in a particular habitat at a particular time.
• Define a population in ecology.

  All of the organisms of a particular species living in a particular habitat at a particular time.
• What is a habitat?

  The place where an organism lives.
• What factors control the distribution and abundance of organisms in a habitat?

  Both biotic (living) factors and abiotic (non-living) factors.
• What is an ecological niche?

  The particular role of a species in its habitat, including its biotic and abiotic interactions.
• How does species distribution and abundance depend on ecological niches?

  It depends on the number and type of ecological niches available within that habitat.
• What does the niche concept state about organisms occupying niches?

  Only one organism can occupy each niche in a given habitat at a given time.
• What happens when two or more species have overlapping niches?

  The best adapted species will out-compete the others for survival and reproduction.
• What is succession in ecological terms?

  The change in species inhabiting an area over time.
• What initiates primary succession?

  It occurs when an area previously devoid of life is first colonized by communities of organisms.
• What is an example of primary succession?

  Colonization after the eruption of a volcano.
• What is secondary succession?

  It occurs with existing soil that is clear of vegetation.
• What are pioneer species?

  Species such as lichens that are adapted to survive in harsh conditions.
• How do pioneer species contribute to soil formation?

  They decompose and add organic matter, leading to the formation of soil.
• What happens to the soil as more organisms are decomposed over time?

  The soil becomes richer in minerals, enabling larger and more varied plants to survive.
• What is a climax community?

  The most productive, self-sustaining, and stable community of organisms that the environment can support.
• What are the two stages of photosynthesis?

  Light-dependent reactions and light-independent reactions (Calvin cycle).
• What occurs during the light-dependent reactions of photosynthesis?

  Electrons are excited to a higher energy level using energy trapped by chlorophyll.
• What is the role of photosystems in photosynthesis?

  They contain chlorophyll molecules that trap light energy.
• What is photophosphorylation?

  The process that generates ATP from ADP and inorganic phosphate during light-dependent reactions.
• What is the final electron acceptor in the light-dependent reactions?

  NADP, which forms reduced NADP when it accepts an electron.
• What is the light-independent reaction also known as?

  The Calvin cycle.
• What is the role of RUBISCO in the Calvin cycle?

  It catalyzes the reaction between RuBP and carbon dioxide during carbon fixation.
• What happens to the unstable 6 carbon intermediate formed in the Calvin cycle?

  It immediately splits into two molecules of glycerate 3-phosphate (GP).
• How is glucose produced in the Calvin cycle?

  One in six GALP molecules is used to make glucose, which is then converted to essential organic compounds.
• What is the function of chloroplasts in photosynthesis?

  They are the site of photosynthesis, containing thylakoid membranes and stroma.
• What is the role of the chloroplast envelope?

  It controls the movement of substances into and out of the organelle.
• What is net primary productivity (NPP)?

  The rate at which energy from the sun is converted into organic molecules that make up new plant biomass.
• What is gross primary productivity (GPP)?

  The energy transferred to primary consumers.
• How do NPP and GPP differ?

  NPP is the energy available for new biomass, while GPP is the total energy produced by photosynthesis.
• What are the stages of primary succession?

  1. Colonization by pioneer species.
  2. Soil formation through decomposition.
  3. Establishment of more complex organisms.
  4. Development of a climax community.
• What are the stages of secondary succession?

  1. Disturbance clears vegetation but leaves soil intact.
  2. Colonization by pioneer species.
  3. Soil enrichment through decomposition.
  4. Establishment of a climax community.
• What are the components of the light-dependent reactions?

  1. Photon absorption by chlorophyll.
  2. Electron excitation and transport.
  3. ATP synthesis through photophosphorylation.
  4. NADP reduction to form NADPH.
• What are the steps of the Calvin cycle?

  1. Carbon fixation by RUBISCO.
  2. Formation of glycerate 3-phosphate (GP).
  3. Reduction of GP to GALP using ATP and NADPH.
  4. Production of glucose from GALP.
  5. Regeneration of RuBP.
• What are the photosynthetic pigments found in chloroplasts?

  Chlorophyll
• What is the site of the light-dependent stage of photosynthesis?

  Photosystems in the chloroplasts
• What does the stroma in chloroplasts contain?

  • Fluid surrounding the grana
  • Enzymes required for the light-independent stage of photosynthesis
• What is the function of the chloroplast envelope?

  It controls the movement of substances into and out of the organelle
• What do starch granules in chloroplasts store?

  The products of photosynthesis