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Unit 3 Topic 2
Ecosystems dynamics
Question | Answer |
---|---|
What is the formula for photosynthesis and cellular respiration? | C6H12O6 + 6O2 <--------> 6CO2 + 6H20 + energy |
Define cellular respiration. | Cellular respiration is the process of releasing chemical energy from the bonds of glucose molecules. |
Define photosynthesis | The process of converting light energy, water, and carbon dioxide into glucose used for energy by autotrophs |
Which trophic level contributes the largest amount of biomass in an ecosystem? | autotrophs (producers) |
What is photosynthetic efficiency? | Photosynthetic efficiency is how well a producer converts light energy into the chemical energy of carbohydrates |
What are some things that can impact photosynthetical efficiency? | Photosynthetic efficiency is can be impacted by availability o light and raw materials, as well as the nature of the organism, temperature and light intensity |
What are the first five trophic levels in an ecosystem? | 1. Autotrophs (producers) 2. Primary consumers 3. secondary consumers 4. tertiary consumers 5. quaternary consumers |
Generally, around how much of the energy at one trophic level is transferred to the next? | Around 10% of the energy at one trophic level is passed on to the next level. The remaining 90% is transformed by metabolism into heat energy and lost to surroundings, or remains as chemical energy in uneaten portion and body waste. |
What is the formula for trophic energy efficiency? | Percentage efficiency = (net productivity of organism/net productivity of previous trophic level) x 100 |
In the carbon cycle, how is carbon released into the atmosphere? (4) | 1. combustion from burning fossil fuels and forests 2. volcanic action 3. cellular respiration 4. diffusion from oceans |
In the carbon cycle, how is carbon absorbed from the atmosphere? (2) | 1. photosynthesis 2. dissolution from the ocean |
What is a carbon sink? | A carbon sink is an area where carbon atoms naturally accumulate away from the normal nutrient cycle |
How is nitrogen cycled throughout the atmosphere? | N2 is absorbed from the atmosphere by denitrifying bacteria and and released back to the atmosphere by denitrifying bacteria and volcanic activity. Nitrate and Ammonium ions are passed between organisms in the biosphere |
What are the key process of the water cycle? (5) | 1. condensation 2. precipitation 3. evaporation 4. transpiration 5. infiltration and percolation |
What is an ecological niche? | the role and space that an organism occupies in an ecosystem, including all its interactions with biotic and abiotic factors |
What is the competitive exclusion principle? | a key ecological concept that states that no two species can occupy exactly the same niche in an ecosystem |
What is a keystone species? | a keystone species is a plant or an animal that plays a unique role in the way an ecosystem functions |
What role do keystone species play in an ecosystem? | Keystone species have a large influence over the stability and biodiversity of the whole community, including species they do not necessarily interact with. |
What is a carrying capacity? | the greatest density of organisms that an area or resource can potentially support. |
What are some biotic and abiotic limiting factors that determine carrying capacity? | Food availability and abundance, number competitors, mates and predators. Number of disease-causing organisms. Availability of nutrients, shelter, refuge from predators, light, water and nesting sites. |
What is the formula for calculating population growth rate and change? | Population growth rate = (birth rate + immigration rate) - (death rate + emigration rate) |
What is the formula for the Lincoln Index? | N = M x n / m M = # caught initially n = # caught 2nd time m = # recaptured that were marked |
What are the three types of population distributions? | 1. random distribution 2. uniform (continuous) distribution 3. clumped (grouped) distribution |
What is random distribution? | a measurement of distribution in which organisms are spaced irregularly. |
What is uniform distribution? | a measurement of distribution in which organisms are evenly spaced. |
What is clumped distribution? | a measurement of distribution in which individuals are grouped together when biotic/abiotic factors are favourable; can be social (schools of fish) or clumping of vegetation |
What type of growth is represented by a J curve? | exponential population growth. It grows exponentially, increasing at a constant rate resulting in a J-shaped curve |
What type of growth is represented by a S-curve | Logistic population growth - population increases rapidly, then, when growth cannot be sustained any longer, the growth rate begins to level off. |
What is nudation and what are some events that trigger the process of nudation? | Nudation is the development of bare sites with no organisms inhabiting them. Catastrophic events such as volcanic eruptions, cyclones, earthquakes and tsunamis can cause the development of these bare sites. |
Explain what Ecological succession is. | The progressive change of communities over time. Starts with pioneer communities beginning to grow. |
What are pioneer species? | Pioneer species are able to grow in poor soils with low nutrients levels. They have the ability to fix nitrogen in the soil. They are small and photosynthetic and disperse seeds effectively, grow rapidly and reproduce rapidly. |
What is a climax community? | The end of succession is marked by a climax community. The community has become relatively stable eg.g old growth forests and rainforests. |
What are the characteristics of a primary succession community? | 1. r-selected organisms - small and fast growing 2. low biodiversity and low biomass 3. simple interactions, food chains 4. small amount poor quality soil, low nutrient levels, unused resources and living spaces, unstable conditions |
What are the characteristics of a secondary succession community? | 1. K-selected organisms - larger and slow growing 2. high biodiversity and biomass 3. complex interactions, food webs 4. large amounts good quality soil and nutrients, living spaces in-demand, stable |
What are 5 areas/categories where human activities are impacting on ecosystems? | Urbanisation, habitat destruction, land and soil degradation, salinity and monoculture practices. |