Cycling in Ecosystems
Describe key steps of the water cycle
Evaporation (from biosphere & geosphere to atmosphere)
Precipitation (from the atmosphere to the Earth's surface)
Transpiration (from biosphere (plants) to atmosphere)
Groundwater flow (through geosphere between reservoirs)
All water = hydrosphere
Are all traits viewed in species today considered adaptations?
No. Adaptations are traits that promote success in an environment.
What is a keystone species?
Species with wide-reaching impact on overall ecosystem.
What are some components of soil?
Sediment from parent material, organic matter (including microbiota), water, air
What does GHG stand for? Name at least 3 GHGs.
Greenhouse gas. CO2, N2O, H2O, CH4, CFCs. These absorb UV & other high-energy radiation, and release IR (heats up Earth).
How does energy flow through ecosystems? What is the trophic pyramid?
Sun -> producers -> primary consumers -> higher order consumers -> decomposers & detritivores
10% of energy from lower level available to next level moving up the pyramid (producers all the way to tertiary consumers)
What is natural selection?
Traits that improve survival & reproduction conserved; traits that harm success tend to be erased.
Differentiate between native, non-native, and invasive species.
Native = naturally occurring in an area
Non-native = not naturally occurring in an area, often introduced by humans
Invasive = non-native and damaging in some way (often outcompetes native species, may do other harm)
Differentiate between sand, silt, and clay (you don't have to be too specific)
Smallest = clay (damp, small pore spaces)
Medium size = silt (medium pore spaces)
Largest = sand (dry, well-draining, large pore spaces)
Are global warming and climate change the same?
No! Global warming = change in Earth's average surface temperature. Climate change results from global warming but has more effects, like more frequent and severe storms, rising sea levels, etc.
What are some sources and sinks in the carbon cycle?
Sources: combustion, cellular respiration
Sinks: photosynthesis
Also two-way movement between the ocean and atmosphere
What are some ways a population can grow? What are some ways a population can shrink?
Grow: births, immigration
Shrink: deaths, emigration
How do lichens help with recovery after an event that wipes out all life in an area?
Pioneer species helps with primary succession. Partnership between fungi and algae. Colonizes rock surface, breaks down into soil. Creates environment for other life to take hold.
What was the Green Revolution and why has it been damaging?
Move from traditional to heavily industrialized agriculture (push to increase productivity). High-input farming degrades soil (unsustainable). Monocultures, pesticides, inorganic fertilizers, irrigation, tilling.
No! Weather = transient, variable, depends on place and time. Climate = long-term average conditions in a place.
What are positive and negative feedback loops? Can you give 1 example of each?
Positive feedback: pushes farther toward extreme (e.g. melting sea ice)
Negative feedback: regulates to maintain equilibrium (e.g. predator-prey cycles)
What is speciation? What are some ways this can occur?
Speciation: divergent evolution where one species splits into different groups that can no longer interbreed.
Allopatric: across different spaces
Sympatric: within the same area, but with a different niche
Competition (interspecific, intraspecific, amensalism)
Predation & herbivory
Parasitism
Mutualism
Commensalism (one benefits, other has no effect)
How does soil salinization occur?
Over-irrigation in hot climates... evaporating water from the surface draws up salts that had leached lower in the soil
What is albedo? How does it relate to melting ice?
High albedo = high reflectivity (low absorption)
Low albedo = low reflectivity (high absorption)
Ice melts & reveals lower albedo surface, absorbs more radiation, heats more (positive feedback)
What are the key steps in the nitrogen cycle and what is the impact of inorganic fertilizers?
Nitrogen fixation, nitrification, denitrification
Eutrophication, algae blooms, hypoxia
What is convergent evolution? Do physical similarities always mean that species are closely related on a phylogenetic tree?
Different starting species evolve similar traits after being exposed to similar environments. No!
Name at least 4 terrestrial biomes
Desert, tundra, boreal forest, temperate deciduous forest, temperate grassland, temperate rain forest, tropical rain forest, tropical dry forest, savannah, mediterranean
What are some ways we can practice regenerative agriculture & protect soil?
Crop rotation/intercropping/companion planting
Less tilling (keeps microbiota alive & reduces CO2 release)
Animal integration
Agroforestry, shelterbelts, contour farming (reduce wind and water erosion)
Habitat for birds, etc. to eat pests
What are mitigation, adaptation, and geoengineering?
Mitigation = reducing GHG emissions to limit warming
Adaptation = changing human practices to limit effects on humans without changing underlying system alteration
Need both of above to combat climate change
Geoengineering = trying to control the climate in new ways (but can be problematic because of complex adaptive, unpredictable system)