APES Midterm

APES Midterm Study Guide - Unit 1: Ecosystems

1.1 - Introduction to Ecosystems
 

1. Explain the difference between symbiosis and mutualism: 

Symbiosis just refers to any organism living in close proximity to another, an example is when humans or any other organism pick up a tapeworm. For it to be mutualism this must be mutually benefiting both organisms, which it is not, therefore it is symbiosis. Mutualism is a symbiotic relationship of organisms that both benefit from the interaction, like bees and flowers through pollination. 

2. Describe the difference between habitat and ecosystem. 

A habitat is just the specific environmental conditions for a species to survive. An ecosystem on the other hand is a specific portion of the environment that is the interaction of the living and nonliving things in a specific area. 

1.2 - Terrestrial Biomes

1. Describe the word biome:

A biome is a region on earth that shares a consistent yearly average temperature and precipitation pattern. Some examples of this are Tropical Rainforests, which have a high annual average temperature and precipitation.

2. Identify a biome with lower annual precipitation and temperature averages than the tropical rainforest. 

The Tundra

3. Identify a desert species and describe how its adapted to the average annual temperature and precipitation of its biome. 

Cactus. The cactus is in the desert which contains little to no precipitation. Due to high temps and low precipitation the cactus adapted to carry a lot of water and not require much rainfall.

4. Describe how a warming global climate may impact the distribution of the tundra. 

Warming of the global climate starts to push other biomes away from the equator as the other parts of the world are warmer than they were. As the other biomes are being pushed the tree line is being pushed up as well, which therefore decreases the size of the tundra, which is a treeless biome.

5. Describe how a warming global climate may impact the distribution of the tropical rainforests. 

Tropical Rainforests are meant to be in hotter areas typically around the equator, but as of global warming they have been starting to spread out. Warming has made the climate more suitable farther north and south of the equator for Tropical Rainforests to thrive.

1.3 - Aquatic Biomes

1. Describe an adaptation of the mangrove tree that enables it to tolerate the salinity levels of estuaries. 

Mangrove trees have an adaptation such as thicker membranes and more pores in their leaves that pump salt out. This adaptation enables them to tolerate the salinity in the water.

2. Identify TWO unique characteristics of estuaries. 

• Where the mouth of the freshwater river connects to the salt water body of water.

• Contain brackish water 

3. Identity TWO ecosystems services of wetlands. 

• They provide habitat for wildlife

• They store floodwaters 

4. Explain why estuaries are highly biodiverse ecosystems. 

Estuaries contain brackish water which is fresh and salt water combined. This makes the species that live there forced to uniquilly adapt to these salinity levels, like mangroves. Also it is very productive as the estuary carries a lot of nutrient sediment for plants to have high biodiversity, therefore helping animals have high biodiversity.

Review of Biogeochemical Cycles: Define the following terms in relation to these cycles:

Reservoir: temporary storage sight of substance

Source: processes that move matter between reservoirs 

Sink: reservoirs that take in increasing amounts of matter of time, they take more than they give

1.4 - Carbon Cycle

1. Explain why the atmosphere is a consequential carbon reservoir. 

The atmosphere is a major carbon reservoir that determines the global climate based on levels of carbon and other gases. The more CO2 that is stored in the atmosphere the more heat that is trapped, influencing the Earth's climate.  Human activities like burning FF increased atmospheric CO2, impacting global warming.

2. Explain the difference between carbon sources and sinks.

Carbon sources are processes that release Carbon into the atmosphere, an example is burning fossil fuels. A Carbon sink is a process in which Carbon is absorbed from the atmosphere, an example of this is plants through photosynthesis. The balance between sources and sinks affect the atmosphere and therefore the global climate.

3. Identify a carbon source and a carbon sink. 

Carbon source= burning fossil fuels or Cell Resp

Carbon Sink= plants through photosynthesis

4. Explain why the carbon released from the combustion of fossil fuels has a different effect on the atmospheric carbon levels than the carbon released during cellular respiration. 

Carbon from fossil fuel combustion increases atmospheric CO₂ by releasing carbon that was stored for millions of years. In contrast, carbon from cellular respiration is part of a natural cycle, returning CO₂ that was recently captured by plants. Fossil fuel use adds new carbon, while respiration recycles existing carbon.

1.5 - Nitrogen Cycle

1. Describe TWO ways that the N cycle differs from the C cycle. 

Compared to the carbon cycle the N cycle is far quicker through its reservoirs. Also the Nitrogen available in the atmosphere is unusable to plants and animals, unlike the Carbon available in the atmosphere.

2. Describe nitrogen fixation. 

Nitrogen Fixation is when the unusable nitrogen is being converted into a usable form of nitrogen, like ammonia and nitrate. This process of fixation occurs through specialized bacteria that can break down the nitrogen gas into usable forms.

3. Identify a biotic and abiotic form of N fixation. 

Biotic= Rhizobacteria

Abiotic=Lightning strikes

4. Describe assimilation

Assimilation is when plants or animals are taking nitrogen and converting it into body tissues. Assimilation can only occur when it is in a solid or fixed form or nitrogen like ammonia or nitrate.

5. Describe ammonification

Process where bacteria and fungi break down nitrogen compounds from dead organisms and waste into ammonia or ammonium. This returns nitrogen to the soil in a form that plants can use.

6. Describe nitrification 

Nitrification is a 2 step process that specialized bacteria convert ammonia or ammonium into nitrites, and then into nitrates. Nitrates are a more accessible form of nitrogen for plants to absorb.

7. Describe denitrification 

Process where specialized bacteria convert nitrates back into nitrogen gas released into the atmosphere. This process typically happens in anaerobic conditions like waterlogged soils.

1.6 - Phosphorus Cycle

1. Describe one way that the Phosphorus cycle differs from the Carbon and Nitrogen cycles. 

The P cycle is different from the other cycles because it does not obtain a gas phase. C and N cycles go through the atmosphere and phosphorus on the other hand is just stuck in rocks.

2. Describe the difference between weathering and erosion in relation to the phosphorus cycle. 

Weathering is when rocks break down from weather conditions and release phosphate into the soil. Erosion is when soil particles that contain phosphorus particles move to new locations via wind and rain.

3. Explain how one of these differences from the question above makes phosphorus a limiting nutrient in many ecosystems. 

A limiting nutrient means that plants don't have enough of this nurturing nutrient to grow. The P cycle is so slow that not enough P particles can be released into the soil for plants to grow. Since the P cycle lacks a gaseous phase, it depends on the very slow process of weathering.

1.7  - Hydrologic Cycle

1. Identify the source of energy driving the hydrologic cycle. 

Suns energy

2. Identify a step of the hydrologic cycle and explain how the sun’s energy drives that step.  

Evaporation. 

Evaporation is a process in which water turns into a gaseous phase from a liquid phase. This happens due to heat on the water causing water molecules to evaporate into vapor and enter the atmosphere. This process is driven by the sun's energy which produces this heat.

3. Describe how vegetation density influences infiltration and transpiration in a given ecosystem. 

Dense vegetation increases transpiration as there are more leaves and pores for water to be released into the atmosphere from. It also enhances infiltration by slowing surface runoff and allowing water to seep into the soil.

4. Identify the largest freshwater reservoir on Earth. = Glaciers

1.8 - Primary Productivity 

1. Describe what is meant by the term primary productivity. 

Primary productivity is the rate of Photosynthesis in the area. When energy is produced over a certain amount of time.

2. Identify the units used to measure primary productivity. 

Energy=kilo calories

Area= meters squared

time= year

3. Describe what is meant by the term respiration loss. 

Respiration loss is the energy plants use up for their own cell respiration. This is otherwise known as the taxes a plant has to pay for upkeep of its body and other vital things to live. 

4. Identify out the formula for calculating NPP.

Npp=Gpp-RL

5. NPP Practice Problems (show your work with units. Just so you’re aware, g C refers to grams of Carbon biomass)
    

   1. Darien High School’s football field has a GPP of 1150 g C/m² /yr and a respiration loss equivalent to 375g C/m² /yr . Calculate the NPP.

2. The Country Club of Darien Golf Course has an NPP of 1,725 g C/m² /yr  and a respiration loss equivalent to 430 g C/m² /yr. Calculate the GPP.

3. Mr. Viderman’s elodea tank had an NPP of 207 kcal/m² /yr and a GPP of 320g kcal/m² /yr. Calculate the respiration loss.     

1.9 & 1.10 - Trophic Levels & 10% Rule

1. Create a trophic pyramid below with organisms found in a deciduous temperate forest. Label each level. 

2. Starting with 8,000 kcal of energy at the producer level, identify the level of energy available at each trophic level. 

Primary producer= 8000

Primary consumer= 800’

Secondary consumer= 80

Tertiary consumer=8

3. Explain the 2nd law of thermodynamics as it relates to trophic pyramids and the 10% rule.

The 2nd law of thermodynamics is when some energy is lost as heat each time energy is transferred. An example of this is when animals from separate trophic levels consume one another, the organisms from the level above only receive about 10% of the energy from the level below. For example, a primary producer stores 8,000 kcal of energy then the primary consumer only has 800 kcal available to it and the rest is lost as heat.

4. Explain why it takes a very large amount of land to support 12 hawks living in a forest. 

Hawks are tertiary consumers which mean they rely on the energy from secondary consumers that has already passed through multiple trophic levels. To be able to sustain 12 hawks in a forest there must be a large land biomass of producers so there can be more energy to go through each trophic level and therefore provide enough at each trophic level. This requires a vast are of land to produce sufficient resources to maintain the food web

1.11 - Food Webs

1. Describe what the arrows in a food web represent. 

The arrows represent the energy being transferred from one organism to another. For example, when a hawk eats a snake it takes 10% of its energy.

2. Describe how a decrease in the populations of frogs in the ecosystem below would impact both a primary consumer and primary producers. 

A decrease in frog populations would increase the number of insects (primary consumers) they prey on, potentially causing overgrazing of plants. This would reduce the plant population (primary producers), impacting the overall ecosystem stability.

3. Identify an organism from the food web below that is both a secondary and quaternary consumer. 

hawk

4. Identify an organism below that is only a secondary consumer in the food web below. 

Frog

APES Midterm Study Guide - Unit 2: Biodiversity

2.1 - Introduction to Biodiversity

1. Define genetic diversity and provide an example. 

Genetic diversity is the variety of genes within a population. For example, different coat colors in a population of wolves represent genetic diversity.

2. Explain how high genetic diversity for the trait you identified in part (a) would be beneficial to a population. 

High genetic diversity in wolf coat colors allows better adaptation to changing environments, such as camouflage in various habitats. This increases survival rates and reduces the risk of extinction from environmental changes.

3. Describe the difference between the terms species richness and evenness. 

Species richness refers to the number of different species in an area, while species evenness measures how evenly the individuals are distributed among those species. Both are important for assessing biodiversity.

4. Define ecosystem diversity. 

Ecosystem diversity is the variety of ecosystems within a given region, encompassing different habitats, communities, and ecological processes.

5. Identify the relationship between ecosystems diversity and species diversity. 

Direct relationships

2.2 - Ecosystem Services

1. Describe provisioning services using an example from an ocean ecosystem.

Provisioning services involve products obtained from ecosystems, such as fish and seafood harvested for human consumption from oceans.

2. Describe supporting services using an example from a grassland ecosystem.

Supporting services include processes necessary for all other ecosystem services, like nutrient cycling. Grasslands provide this service by decomposing organic matter and maintaining soil fertility.

3. Describe regulating services using an example from a tropical rainforest ecosystem.

Regulating services involve ecosystem functions that maintain balance, such as tropical rainforests sequestering carbon and regulating global temperatures.

4. Describe cultural services using an example from a wetland ecosystem.

Cultural services are non-material benefits, such as recreation and inspiration. Wetlands offer birdwatching opportunities and contribute to local cultural identity.

2.3 - Island Biogeography

1. Identify the two rules of the Theory of Island Biogeography 

Islands closer and larger have more species biodiversity

2. Explain why the two rules you stated above help determine the biodiversity found on islands. 

Larger islands provide more habitats and resources, supporting diverse populations. Proximity to the mainland allows for easier immigration of species, increasing biodiversity.

3. Explain why islands generally have a higher percentage of specialist species.

Islands often have unique conditions and limited resources, favoring species adapted to specific niches and reducing competition with generalists.

2.4 - Ecological Tolerance 

1. Define each of the following zones: 

   1. Optimal range:  where species thrive

2. Zone of physiological stress:  survivable is possible but growth and reproduction is reduced

3. Zone of intolerance: he range where the species cannot survive

2. Explain the ecological range of tolerance a plant species has for soil moisture. 

A plant species may thrive in moderate moisture, experience stress in very dry or waterlogged conditions, and die in extreme drought or flooding.

3. Describe how genetic biodiversity in the plant population would be beneficial in the example you explained above if an area experiences a prolonged drought. 

High genetic biodiversity may include drought-tolerant variants, allowing some plants to survive and reproduce, preserving the species during environmental stress.

2.5 - Natural Ecosystem Disruption

1. Identify an example of a periodic, episodic and random event: 

Periodic: Seasonal flooding.

Episodic: Volcanic eruptions.

Random: Meteor strikes.

2. Describe one way that earth’s orbit around the sun naturally changes over time. 

Earth’s orbit shifts between more circular and elliptical shapes (eccentricity) over thousands of years. This is one of the three milankovitch cycle.

3. Explain how variation in earth’s orbit influences global climate. 

These cycle impact the climate by tilting the hemisphere closer or further away from the sun, or brings the orbit closer or farther away from the sun. 

4. Identify the relationship between global atmospheric temperature and sea level. 

Warmer means level rises and vise versa. Direct relationship of increase to increase and decrease to decrease

5. Explain one cause for the relationship you identified in part (d)

Global warming accelerates ice melting in polar regions, adding water to the oceans and increasing sea levels.

2.6 - Adaptations

1. Define adaptation: 

Adaptation is a trait that improves an organism’s survival and reproduction in its environment

2. Describe the selective pressure that selected for giraffes to have longer necks over time. 

Selective pressure came from competition for food, as giraffes with longer necks could reach leaves higher in trees, giving them a survival advantage.

3. Describe an adaption in a tundra species. 

The Arctic fox has thick fur and a compact body to retain heat and survive extreme cold in the tundra.

2.7 - Ecological Succession

1. Describe how moss and lichen are able to colonize bare rock and explain their role in the regrowth of a forest ecosystem.  

Moss and lichen secrete acids that break down rocks into soil, enabling plant growth. They are essential for initiating soil formation during primary succession.

2. Describe the difference between primary and secondary succession. 

Primary succession occurs on bare surfaces with no soil, while secondary succession happens in areas with existing soil after disturbances.

3. Describe the characteristics of pioneer species and provide an example.

Pioneer species are hardy, fast-growing, and able to thrive in harsh conditions. An example is lichen.

4. Describe the characteristics of climax community species and provide an example. 

Climax species are stable, long-lived, and dominate at the final stages of succession. An example is oak trees.

5. Define keystone species. 

A keystone species is one that has a disproportionately large impact on its ecosystem relative to its abundance.

6. Define indicator species. 

An indicator species is sensitive to environmental changes and signals the health of an ecosystem.

7. Identify an example of a top predator keystone species and an ecosystem engineer keystone species.

A top predator keystone species is the wolf, and an ecosystem engineer keystone species is the beaver.

8. Describe one example of how the removal of a keystone species could destabilize an ecosystem. 

The removal of wolves from Yellowstone caused overpopulation of deer, leading to overgrazing and loss of vegetation, destabilizing the ecosystem.