Unit 1 Ecosystems, Biomes, and Energy Flow Review

Flashcards generated from Unit 1 lecture notes covering Ecosystem Basics, Biomes, Biogeochemical Cycles, Primary Productivity, and Trophic Energy Flow.

What is symbiosis?

Any close and long-term interaction between 2 organisms of different species.

What is mutualism, and what example is given in the notes?

A relationship that benefits both organisms; an example given is a coral reef.

What is commensalism, and what example is given in the notes?

A relationship that benefits 1 organism and does not impact the other; an example given is birds nesting in trees.

What is parasitism?

A relationship where 1 organism lives on or inside another host organism.

Why does competition for limited resources reduce population size?

Because fewer resources are available, resulting in fewer organisms being able to survive.

What is resource partitioning?

When different species use the same resource in different ways to reduce competition.

What are the three types of resource partitioning described in the notes?

1. Temporal (using resources at different times), 2. Spatial (using different areas of a shared habitat), and 3. Morphological (using different resources based on different evolved body features).

What is a biome, and what two main characteristics define it?

An area that shares a combination of average yearly temperature and precipitation; defined by yearly temperature and precipitation.

What are the characteristics of tropical range biomes (rainforest, seasonal/savanna)?

Closer to the equator so warm and wet. Tropical rainforests have year-round frequent rainfall and the most biodiversity on Earth; savannas have long dry seasons, grasses, and grazing animals.

What are the characteristics of temperate range biomes (grassland, seasonal/rainforest)?

Hot summers, cold winters, and moderate rain (except temperate rainforest which has heavy rainfall); located at mid-latitudes between $30^\bullet\text{--}60^\bullet$.

What are the characteristics of boreal forest and tundra biomes?

Boreal forests have long, cold, dry winters and short, cool, wet summers. Tundra is the coldest and driest biome, located at $60^\bullet+$ latitude.

How does distance from the equator affect biomes, and how can biome locations change?

Distance from the equator (latitude) determines temperature and precipitation; biomes can shift location as climate changes on Earth.

How are desert plants adapted to their environment?

They are adapted to prevent water loss due to low rainfall and high temperatures.

What are three primary human water sources mentioned in the notes?

Rivers, lakes, and freshwater wetlands.

How is a marine biome defined?

A large aquatic ecosystem defined by a high concentration of dissolved salt.

What are estuary biomes, and what are two examples?

Areas where rivers empty into the ocean; examples include salt marshes and mangrove swamps.

What is a freshwater wetland?

An area with soil submerged or saturated in water for at least part of the year, but shallow enough for emergent plants.

What are intertidal zones, and what must organisms adapt to there?

A narrow band of coastline where organisms must adapt to surviving crashing waves and heat during low tide.

Where is the majority of Earth's freshwater found?

In ice caps and glaciers.

What is a carbon source, and what examples are listed in the notes?

Processes that add carbon to the atmosphere; examples include fossil fuel combustion, animal agriculture (cow burps), deforestation, and cellular respiration.

What is a carbon sink, and what reservoirs act as carbon sinks?

A reservoir that stores more carbon than it releases; examples include oceans, plants, and soil.

What are the short-term and long-term carbon reservoirs?

Short-term reservoirs: soil and atmosphere. Long-term reservoirs: fossil fuels, sedimentary rocks, and ocean layers.

How is a steady state maintained between the atmosphere and biosphere in the carbon cycle?

Photosynthesis removes $CO_2$ from the atmosphere while cellular respiration releases $CO_2$ back, keeping them balanced.

How does fossil fuel combustion alter atmospheric carbon levels?

It increases carbon stored in the atmosphere because it releases stored carbon as $CO_2$.

What is the largest major reservoir for nitrogen?

The atmosphere.

What is nitrogen fixation?

The process of $N_2$ gas being converted into biologically available $NH_3$ or $NO_3^-$ / $NO_2^-$.

What is nitrogen assimilation?

Plants and animals taking nitrogen in and incorporating it into their bodies.

What is the order of steps in the nitrogen cycle pathway shown in the notes?

$N_2$ nitrogen gas \rightarrow nitrogen fixation \rightarrow organic nitrogen \rightarrow ammonification \rightarrow ammonium ($NH_4^+$) \rightarrow nitrification \rightarrow nitrate ($NO_3^-$) / nitrite ($NO_2^-$) \rightarrow denitrification.

How do humans perform synthetic nitrogen fixation?

By combusting fossil fuels to convert $N_2$ gas to nitrate.

What are the sources, sinks, and major reservoir of the phosphorus cycle?

Sources: phosphate rocks and soil. Sinks: sedimentary rock and ocean sediments. Major reservoir: sedimentary rock.

Why is phosphorus often a limiting nutrient in aquatic ecosystems?

Because the weathering process (wind and rain breaking down rock to release phosphate) is extremely slow.

What phase is absent in the phosphorus cycle?

The phosphorus cycle has no gas phase and moves strictly through rocks and sediments.

What drives the hydrologic cycle, and what are its sinks and sources?

Energy source: the sun drives the cycle. Sinks: oceans and groundwater. Sources: evaporation and evapotranspiration.

What reservoirs serve as human drinking water sources?

Ice caps and groundwater.

What is infiltration in the hydrologic cycle?

When water runoff trickles through soil down into groundwater aquifers.

What is primary productivity, and what unit is it measured in?

The rate that solar energy is converted into organic compounds via photosynthesis, measured in energy per area per time ($\text{kcal/m}^2/\text{yr}$).

What formula defines Net Primary Productivity (NPP)?

$\text{NPP} = \text{GPP} - \text{RL}$, where GPP is Gross Primary Productivity (total solar energy captured via photosynthesis) and RL is Respiration Loss.

If GPP is $600\,\text{J/m}^2/\text{yr}$ and Respiration Loss is $450\,\text{J/m}^2/\text{yr}$, what is the NPP?

$\text{NPP} = 600\,\text{J/m}^2/\text{yr} - 450\,\text{J/m}^2/\text{yr} = 150\,\text{J/m}^2/\text{yr}$.

Why can a pyramid represent different trophic levels, and which level has the most biomass?

Because the amount of usable energy decreases as you move up the food chain (lost as heat); producers have the most biomass.

What are the four trophic levels listed in order from base to top?

1. Producers, 2. Primary consumers, 3. Secondary consumers, 4. Tertiary consumers.

What is the $10\%$ rule in energy flow?

Since energy is needed for growth and only $10\%$ of energy transfers from 1 trophic level to the next, only $10\%$ of biomass can be grown.

Which physical law states that energy is lost as heat during energy transfers?

The 2nd law of thermodynamics.

If producers contain $100{,}000\,\text{J}$ of energy, how much energy is available at the secondary consumer level?

$1000\,\text{J}$ (divided by 10 twice).

If secondary consumers have $100\,\text{kg}$ of biomass, how much biomass was required at the producer level?

$10{,}000\,\text{kg}$ (multiplied by 10 twice).

What is the difference between a food web and a food chain?

A food web shows multiple paths of matter and energy flow through an ecosystem, whereas a food chain shows one direct path.

What do the arrows in a food chain represent?

The direction of energy flow.

According to the notes, what is the effect of removing deer from an ecosystem?

It impacts predator population food sources and increases plant vegetation growth due to less grazing.