additional practice for unit 1

1 INTRO TO ECOLOGY AND BIOSPHERE

1. Explain why global climate patterns are largely determined by the input of solar energy and the earth’s movement in space.

   The amount of solar energy determines the climate of an area. It warms or cools to ocean and land. The angel of the earth’s movement determines the climate of certain area. The spin of the earth determines how long to solar energy is available which determines day and night.

2. List key factors that can regionally and locally modify climate

Latitude, altitude, wind/ocean patterns, proximity to ocean/bodies of water, cloud cover, human activity

• Earth can be divided into latitudinal zones (or bands) that describe broad climate zones.

  a. Sketch the planet (in this case the sketch IS the answer), divide it into three major
  latitudinal zones (indicate at which latitudes you are dividing your climate zones) and
  label the climate zones (note - the answer is NOT low, mid, and high-latitudes).
  b. List the two parameters that are primarily used to define climate, and briefly
  explanation why global climate patterns are largely determined by solar input and
  earth's movement in space (remember to explain the patterns of both parameters).

• Biomes are characterized by distinct climate patterns that result in characteristic patterns of vegetation (and animals).
  a. List the three primary parameters that determine the climatic conditions of a biome.

  temp, precipitation, and seasonality
  

  b. One of these parameters impacts one biome in particular - list the parameter and the biome in question and explain how this impacts where biome is found compared to other biomes.

  desert, This parameter is key because it limits plant growth and influences the adaptation strategies of organisms in deserts, such as water conservation and the ability to withstand extreme heat. Compared to other biomes, deserts are more sparsely populated by life due to the challenging environmental conditions created by low precipitation.

• Biomes typically form broad latitudinal bands(ish - distribution of continents, and regional features like mountains will impact this).
  a. The Alpine biome is primarily defined by altitude. List the other two parameters that
  are generally used to describe the climate conditions characteristic of a biome and
  briefly describe what metrics are used to do this (Hint think of the definition of a
  climate zone).

  • Temperature:

    • Metrics used: Average annual temperature, seasonal temperature variations, and extreme temperatures(maximum and minimum temperatures).

    • These metrics help define the temperature ranges typical of a biome, determining whether it's tropical, temperate, or polar. They also influence plant and animal adaptations, as different species thrive in specific temperature ranges.

  • Seasonality:

    • Metrics used: Length and severity of seasons (winter, spring, summer, autumn), timing of precipitation patterns, and temperature fluctuations throughout the year.

    • These metrics describe how temperatures and precipitation vary over the course of a year, helping to classify biomes based on their seasonal patterns (e.g., seasonal forests vs. evergreen forests, or tundra vs. tropical forests). Seasonality determines growing seasons for plants and animal behavior, such as migration or hibernation

    • b. Use a sketch (the sketch of the "biome pyramid" IS the answer to this question) to
      organize the major biomes four major latitudinal climate zones (name them),organize the biomes according to the two paramete

  c. Choose two biomes and compare and contrast them in terms of their characteristic climate conditions, primary vegetation, typical animals that inhabit them, and where they are found geographically (i.e. list example locations).

Deserts and tropical rainforests both have the same average temperature. The changing factor between the two is that the deserts have low precipitation and the rainforest has high precipitation. The rainforest can then sustain more life. It has more vegetation and can have life of more varitety. The deserts can only sustain orgaisms that can survive in hot and dry climate.

• List 5 key physical and chemical properties that characterize aquatic biomes.

  Salinity – The concentration of dissolved salts in the water. This is a key factor in distinguishing between freshwater (low salinity) and marine (high salinity) biomes. The salinity affects the types of organisms that can thrive in the ecosystem.

• Temperature – The water temperature affects the metabolic rates of aquatic organisms and influences species distribution. Water temperature can vary by depth, location, and season, playing a crucial role in ecosystem dynamics.

• Light Availability – The amount of sunlight that penetrates the water. In aquatic environments, light decreases with depth, impacting photosynthesis in plants and algae, which are crucial for energy production in these ecosystems.

• Dissolved Oxygen – The amount of oxygen dissolved in water, which is vital for respiration in most aquatic organisms. Oxygen levels can vary depending on temperature, salinity, and water movement.

• pH Levels – The acidity or alkalinity of the water. Aquatic organisms have specific pH ranges in which they can survive, and changes in pH can significantly impact the health of the ecosystem, affecting species diversity and water chemistry.

1. Describe how water depth and distance to shore result in stratification of abiotic factors characterizing aquatic communities/ecosystems.

   1. Water Depth

   • Light Penetration: As depth increases, less sunlight penetrates the water. The upper layer, called the photic zone, receives enough light for photosynthesis to occur. Below this, the aphotic zone receives no light, so photosynthesis is not possible.

     • In shallow waters, light can penetrate deeper, supporting more plant and algae growth.

     • In deeper waters, the lack of light limits primary production, affecting the types of organisms that can survive.

   • Temperature: Water temperature also varies with depth. In the epilimnion (upper layer), the water is typically warmer due to direct sunlight, while in the hypolimnion (deeper layer), the temperature is colder and more stable.

     • In deeper bodies of water, temperature differences between layers create thermal stratification, often leading to a thermocline — a distinct boundary between warm and cold water layers.

   2. Distance to Shore

   • Proximity to Land: The area closer to the shore is typically more influenced by land-based factors, such as temperature fluctuations, nutrients from runoff, and wave action. This is known as the littoral zone.

     • Shallow areas near the shore tend to be warmer, more nutrient-rich, and have greater light penetration, which supports a high diversity of plant and animal life.

     • The limnetic zone, which is farther from shore, tends to be more uniform in temperature but is also affected by water depth and nutrient availability.

   • Wave and Currents: Water movement near the shore creates currents, leading to mixing in the upper layers (epilimnion), while deeper areas experience more stagnant conditions. This can affect nutrient distribution and oxygen levels, contributing to differences in species composition.

     • In shallow, coastal areas, nutrient mixing is higher, which supports a wide variety of organisms.

     • Farther from shore, in the pelagic zone (open water), there is less mixing, and the water tends to be more stable, with different organisms adapted to these conditions.

   Resulting Stratification of Abiotic Factors:

   • Temperature and light decrease with increasing depth, creating distinct layers with different living conditions (e.g., the warm, light-rich surface zone vs. the colder, darker deep zone).

   • Oxygen levels may be higher near the surface where photosynthesis occurs but can decrease in deeper waters due to lower productivity and limited water mixing.

   • Nutrient availability can vary, with the shallow areas often being more nutrient-rich due to runoff from land, while deeper areas might be limited by the availability of nutrients unless water mixing brings them to the surface.

   This stratification leads to distinct ecological zones within aquatic ecosystems, with different species adapted to each layer's unique environmental conditions.

2. Figure 40.1 (52.1) in your text gives you a visual overview of factors that strongly affect species distribution. Notice that the factors that have the strongest effect on terrestrial systems are different from the ones affecting aquatic systems.
   a. Create a flow chart that shows these differences and then bring the chart to a
   common end with dispersal and interactions.

   ?????

3. b. For any of the four communities represented (tropical forest, desert, coral reef, or
   deep-sea vent), describe all the factors that work together to determine the location
   of a single species found in that community.

   1. Temperature

   • Coral reefs are found in tropical and subtropical regions, where water temperatures typically range between 20°C and 30°C (68°F to 86°F). Corals are highly sensitive to temperature changes, and their symbiotic relationship with zooxanthellae (photosynthetic algae) requires stable, warm temperatures.

   • Species like Acropora corals require consistent warmth to maintain the photosynthesis process within their symbiotic algae, which provides the corals with nutrients. Water temperatures that are too cold or too hot can cause coral stress, bleaching, and death.

   2. Light

   • Corals need sufficient sunlight for the zooxanthellae to perform photosynthesis. The photic zone (the upper layer of the ocean where light can penetrate) is essential for corals.

   • Corals typically live at depths of up to 50 meters (though some can go deeper) where light levels are still high enough for photosynthesis. Without enough light, corals cannot thrive and will be unable to grow and reproduce effectively.

   3. Salinity

   • Coral reefs require saltwater, typically with a salinity level of 32-42 PSU (Practical Salinity Units), which is characteristic of tropical seas. Significant deviations from this salinity range, such as in brackish waters, can affect the survival of coral species.

   • Fluctuations in salinity, often caused by freshwater influx from rivers or heavy rainfall, can be stressful for corals and disrupt the delicate balance of their ecosystem.

   4. Nutrient Levels

   • Coral reefs thrive in nutrient-poor waters because excessive nutrients (like nitrogen and phosphorous) promote algal overgrowth that can smother corals. However, some nutrients are necessary for coral growth and support the photosynthetic activity of zooxanthellae.

   • Coral species like Acropora are adapted to living in nutrient-poor environments, and the symbiotic algae help provide most of the nutrients needed for coral growth.

   5. Water Movement and Currents

   • Water currents play a vital role in the location of coral species by transporting plankton and other food sources, as well as facilitating the reproductive dispersal of coral larvae.

   • Wave action can also help corals by ensuring proper oxygenation and preventing the buildup of sediment, which can smother coral polyps.

   • Coral species like Acropora prefer areas with moderate wave action, as they benefit from the constant flow of oxygenated water.

   6. Substrate (Surface for Attachment)

   • Corals need a stable, solid substrate (such as rock or older reef structures) to attach their polyps and grow. Coral larvae settle on hard surfaces, and the availability of such surfaces plays a key role in the distribution of coral species.

   • Shallow, rocky seabeds in tropical regions provide the ideal conditions for the growth of coral colonies.

   7. Competition and Symbiosis

   • Coral species are influenced by their competition with other species (like algae or other corals) for space and resources. Acropora corals are fast-growing and often compete with other coral species for optimal light and space.

   • The symbiotic relationship between corals and zooxanthellae algae is a defining factor that affects coral distribution. Without this mutualistic relationship, the coral species would not be able to survive in the nutrient-poor waters of a reef.

   8. Human Impact and Environmental Stress

   • Pollution, such as agricultural runoff, oil spills, and sewage, can affect coral health by introducing harmful substances that disrupt the reef ecosystem. Overfishing, especially practices like blast fishing, also damages coral habitats.

   • Climate change and the associated ocean acidification and rising sea temperatures significantly affect coral species. Corals are especially vulnerable to rising sea temperatures, which can cause coral bleaching, where the corals expel their zooxanthellae due to stress, leading to a loss of their vibrant colors and a weakened state.
     

1 ARG INTRO TO ECOLOGY

2. Define what emergent properties are and give two examples.

Emergent properties are characteristics or behaviors that arise from the interaction of simpler components within a system. One example is coral reefs. They provide structure and stability to the marnien life. They can life or hide in the structure. They filter the water and increase the photosynthesis by symbiotic(close) relationships with photosynthetic organisms. Meaning there are more nutrients present in the water.

Biosphere→Ecosystems→ Community→Populations→Organisms→Organ Systems→Organ→Tissue→Cells→ Organelle→Molecules


1. All life is organized into three domains. List the three domains below and identify which
are prokaryotic and which are eukaryotic.

The three domains are bacteria, archaea, and eukarya. Bacteria and archaea are
prokaryotic and eukaryotic is eukaryotic.

2. List the four major life groups that form the Eukarya.

Kingdom Plantae, Kingdom Animalia, Kingdom Fungi, and protists

9. Define what a terrestrial biome is and describe which two abiotic factors are most
important in determining their distribution

A terrestrial biome describes similar areas around the world that can support similar
organisms. Their personal cimalte allows for certain growths to take place. The
temperature and amount of precipitation in these areas helps determine if it can
sustain the same type of life. Other abiotic factors are important as well, but
especially for vegetation, these factors need to be similar to built the same kind of
ecosystem

12. List the most important factors that influence the distribution of aquatic biomes.

Freshwater biomes are closely linked to the soils and biotic components of the surrounding
terrestrial biome. Freshwater biomes are also influenced by the patterns and speed of water
flow and the climate to which biome is exposed. In both fresh and marine environments,
communities are distributed according to water depth, degree of light penetration, distance from
shore, and whether they are found in open water or near the bottom

19. Describe the role of abiotic factors in limiting a species’ distribution.

Abiotic factors such as temperature, water, oxygen salinity, sunlight, and rocks and soil. The
salinity of wetlands is important to keep the organisms living inside content. An increase in
salinity may push the organisms into one particular area away from the source of salinity

20. Describe the role of biotic factors in limiting a species’ distribution.

Biotic factors such as predation, herbivory, pollinators, food resources, parasites, pathogens,
and competing organisms. Pathogens can attack and kill certain species like an epidemic. A
species may need to emigrate from one another in order not to catch the disease. A lack of
pollinators can cause a plant to no longer be able to reproduce from the lack of cross pollination. Plants may begin to grow closer together to make cross pollination easier

2 POPULATION ECOLOGY

a. Define dispersion.

The way organisms disperse from one another. The patterns individuals of a population distribute within an area.

b. List the three main patterns.

Uniform, random, clumping

c. Describe each of the three main patterns.

Uniform is when individuals of a population stay a uniform distance from one another due to territorial reasons. Random dispersion is when individuals disperse not taking into account of presence of other individuals. The best example of this is seeds dispersing randomly in the wind. Clumping happens when individuals find a resource and stay there to keep obtaining that nutrients. This is so they have a higher chance of survival.

d. Explain the mechanism that causes each of these different patterns.

Uniform is caused by interactions between individuals. Random is determined by the wind and rain patters. They don’t have strong interactions that deter them from one another. Clumping happens because resource availability and behavioral patterns.

e. Compare and contrast these three patterns.

f. Come up with a scenario of how an organisms is typically dispersed (e.g.
penguins, grizzly bears, bees, wild flowers in a meadow) and practice arguing
what mechanism you think causes their scenario or explain how you would
predict them to be dispersed.

Penguins are uniform dispersion. They are territorial of their eggs and the males fight to protect their eggs and wont let anything get in their space.

2. Draw a plot that describes the change in population size over time (generations) and a
second plot that shows the change in the per capita population growth rate over time for
both exponential vs logistic growth.

Population Size: Exponential growth occurs when a population grows at a constant rate without any limiting factors (like resources or space). The population size increases rapidly over time.

Logistic growth accounts for environmental limits. As the population approaches the carrying capacity (K), the growth rate slows and eventually levels off.

• Exponential Growth:

  • Population size increases exponentially, with a constant rate of growth.

  • The per capita growth rate remains constant (rr) throughout.

• Logistic Growth:

  • Population size grows rapidly at first but slows as it approaches the carrying capacity KK.

  • The per capita growth rate starts high, then decreases as the population nears KK.

3. Explain why a constant per capita rate of growth (rmax) for a population produces a curve
that is J-shaped

The J-shape: This results in a curve that initially increases slowly (as the population is small), but as time passes and the population grows, the growth rate accelerates and the curve steepens. The curve looks like a "J" because it starts with a slow rise and then shoots upward more steeply as the population size increases.

4. Explain why a population that fits the logistic growth model increases more rapidly at
intermediate size than at relatively small and large sizes

• At small sizes: When the population is small, the growth rate is initially exponential because there are plenty of resources (food, space, etc.) available for the population to use. However, the population growth is still somewhat limited by factors like predation and disease, and the growth rate is still increasing, but not as fast as it could be.

• At intermediate sizes: As the population increases, there are still sufficient resources available, but the population has grown large enough to experience a more significant amount of intraspecific competition (competition within the species). The growth rate accelerates because the individuals in the population are reproducing in large numbers, but the effects of resource limitation and competition have not yet slowed it down significantly. This results in the most rapid growth, as the population size is large enough to generate substantial births but still below the carrying capacity, where environmental limits start to come into play.

• At large sizes: As the population approaches the carrying capacity of the environment, the growth rate starts to slow down because resources become limited. Competition for food, space, and mates intensifies, leading to fewer births and higher mortality rates. At this point, the growth rate begins to level off and eventually stabilizes, becoming zero once the population reaches carrying capacity

5. Argue what type of population model you would expect to best describe a species with
Type I compared to Type III survivorship.

A species in type I is a mammal that produces few offspring and lives a long life. A species in type III is a fish, seeds, and larvae organisms that focuses on reproduction over survival. They produce lots of offspring early on in life and die off young because they used all their energy towards reproduction.

6. Argue what type of population model you would expect to best describe a r-selected
compared to a K-selected species.

K: carrying capacity (absolute # when cpaitalized)

N: population size

r: per capita growth rate (per indivudal) , made up of birth rates and death rates, per capita death rates are (on average per individual), individuals died per year divided by the number of populaiton alive total

K would most likely have a logistic growth graph. r would have a expoential graph.

7. Argue whether you would expect (a) the removal of predators, (b) favorable climate
conditions, or (c) competition for resources to cause a population to shift most quickly
from an exponential to a logistic growth model. Note: your argument should also include
why the other two options either do not cause this shift, or the shift occurs more slowly
than the one you are arguing for.

I would expect competition for resources to cause a population to shift from exponential to logistic growth model. The compeiition for resources would limit the amount of organisms a community can support. Some organisms would die off. They would not be able to have enough resources to survive. They would reach their carrying capacity for the amount of resources that are avalible. The removal of predators and favorable climate would make the population go up and not reach K.

8. An organism’s life history comprises the traits that affects its schedule of reproduction
and survival.
a. Explain how trade-offs of maximizing reproduction or survival produce different
life history strategies (evolutionary pressure).

Some organisms like fish create thousands of eggs in order to create a larger population. This energy is spent and the organism cannot survive long because it used all its energy on reproduction. Some organisms chose survival. They create only a few offspring, take care of them, and focus on their survival and not the amount of offspring they produce.

b. Argue which of the following examples are most likely to be K-selected and which are most likely to be r-selected species. Remember to make a statement about why their characteristics more likely make them fall in one or the other category; refer to your answer for part a

i. Long-lived tree species that grows slowly and reproduces infrequently
with a small number of seeds per reproductive event.

This is an example of K because the tree does not need to reproduce. The tree population is at carrying capacity. The tree is more focused on growth and maintaining its integrity and not for the seeds it produces.
ii. A small fast-growing annual plant that produces many small seeds that
disperse widely.

This is an example of r selected species because it is more focused on the per capital growth rate. Its focus is on reproduction. They create a vast amount of offspring. Their survival rate is lower due to this imput of energy to reproduction and not survival.

iii. A small mammal that has many offspring per reproductive event but has a
short lifespan.

This is an example of r selected species because it is more focused on the per capital growth rate. Its focus is on reproduction. They create a vast amount of offspring. Their survival rate is lower due to this imput of energy to reproduction and not survival.
c. Argue whether you would expect to find the plants described in scenarios a and b

????

2 ARG POPULATION ECOLOGY

1. Explain the difference between the per capita population growth rate r compared to
   the realized per capita growth rate and the maximum per capita growth rate

This refers to the actual growth rate of a population in a given environment, considering the influence of factors such as resources, environmental conditions, and any limiting factors (e.g., food, space, predation, disease).

This refers to the growth rate of the population under ideal conditions, where resources are unlimited, and no environmental factors restrict the population's ability to grow.

2. Explain under which conditions you would expect to see exponential growth occur.

You would expect to see exponential growth under an abundance of food and freedom to
reproduce.

3. Define the term carrying capacity and list six examples of limiting resources that can
   influence the carrying capacity of an ecosystem.

Carrying capacity is the maximum population size that a particular environment can sustain.
Limiting resources that can influence this is energy, shelter, refuge from predators, nutrient,
ability water, and suitable nesting sites

• Population rate decreases at N approaches K

5. List and define the three key variables that form the life history of a species (
   life history traits).
   

The three variables that form life history are how often the organism reproduces, the number
and size of offspring produced per reproductive episode, and when reproduction begins

6. Describe how each major life history strategy attempts to maximize reproductive output.
   Keep in mind that the concepts of K-selection and r-selection represent two extremes in a range of possible life histories. Each species has its own unique life history strategy.
   

K selection is for traits that are advantageous at high densities. K selection is to operate in
populations living at a density near the limit imposed by their resources where competition
among individuals is strong. R selection is for traits that maximise reproductive success in
uncrowded environments. It occurs in environments in which population densities are well below carrying capacity or individuals face little competition

density-independent regulation: A birth rate or death rate that does not change with
population density.
density-dependent regulation: A death rate that increases with population density or a
birth rate that falls with rising density

7. Negative Feedback Mechanism Explanation Example
   

Competition for resources: Higher levels of an organism leads to overcrowding. This can decrease the amount of reproduction due to limited space and resources when crowded together. Farmers apply fertilizer to crops to reduce nutrient limitations on crop yield.

disease: If the transmission rate of a disease increases, the diseases impact is density dependent. Flu and tuberculosis are spread through the air while an infected person
sneezes or coughs. Both affect people in larger populations and not rural areas.

Territoriality Limit: population density when space becomes the resource for which individuals
compete. Cheetahs use chemical markers in urine to warn other cheetahs of their territorial boundaries. The presence of surplus, or non breeding individuals is a good indication that
territoriality is restricting population growth.

Intrinsic factors: Regulate population size, Reproductive rates of white footed mice in field
enclosure can drop even when food and shelter are abundant. Aggressive interactions and hormonal changes within individual mice that delay sexual maturation and depress the immune system

3 ECOLOGICAL COMMUNITIES

1 chart on extra questions on 3 ARG

2. Compare and contrast how competition, predation, and mutualism differ in their effects
on members of the two interacting species.

Competition is when organisms are competing for the same resource to survive. Predation is when an organism uses another organism as its food source. Mutualism is when individuals of different species assist one another in a way that is mutually beneficial.

3. Army ants march across the forest floor flushing out and consuming insects, spiders,
and even small lizards. However, they flush out considerably more potential prey than
they can consume so there are a lot of prey that flee the ant army – the ant army keeps
moving on and doesn’t chase them down because plenty remain in their pathway for
them to consume. There are bird species that follow the army ants and eat some insects
as they scurry out of the path of the army ants.
a. Briefly argue what type of species interaction is being observed.

This relationship is called predation. The ants get a food source while the insects, spiders, and lizards are their prey. The ants benefit from this interaction while the prey loses and has a negative impact on their fitness.

b. Assume that the birds develop a pattern of behavior where they not only follow behind the ant army but are also found on the sides, this results in some of the larger prey (e.g. lizards) that would normally be able to flee to be forced back into the path of the army ants. It is much more efficient for the army ants to kill and eat larger prey like lizards, especially since they frequently carry excess prey back to their colony. Briefly argue what type of species interaction is now being observed between birds and ants.

This is an commensalism interaction. The birds help the ants by making the lizards a more likely food source. This action does not affect the bird’s fitness. The ants’ fitness is improved because they gain more resources.

c. Assume that the birds have become increasingly bold, they now actively invade the path of the army ant and start eating some of the prey that are most valuable to the army ants. Briefly argue what type of species interaction is now being observed between birds and ants.

This interaction is considered a parasitism relationship. The birds begin taking the ants’ resources. The birds’s fitness is positively affected. The ants’s fitness is negatively affected. The birds are taking advantage of the work that the ants do to corral the lizards.

d. Assume that researchers have analyzed the gut contents of ant birds and found army ants within their stomachs. Briefly argue what type of species interaction is now being observed between birds and ants.

This is an explotiative/predation relationship because the birds use the ants to improve their fitness. The ants fitness decreases.

4. Use the concept of competitive exclusion to argue what you think the expected outcome
will be if two species with

(a) identical niches

One species will be domainant while the other will go extinct. This will happen because the species will be competing for the same resouce in the same area. One organism will adapt better than the other.

(b) overlapping ecological niches compete for a resource.

If their niches overlap, they do not compete in the same areas for the same resource. This means that their competition is limited. The different species are able to live in peace with one another. They can coexist without issues of comeptition. They have their own specialized niches, to be specialized to hunt for resources in their own area.

5. Come up with an example that illustrates the difference between a species fundamental
and realized ecological niche.

The realized niche is when there is competition. Krill get phytoplankton from under iceburgs when there is competiton for phytoplankton in the open ocean. They hunt there because there is no competion and they are specialized to utilize this resource. The fundamental niche is when there is no competition for resources. If there was no compeition for the krill, they could get phytoplankton in the open ocean and under ice glaciers.

6. Explain how species interactions can function as selective (evolutionary) pressures.

Species interactions influence other organisms to get better traits that are more adapted to survival. If trees are taller than others and getting all the sunlight, then the other trees will change through evolution to become taller as well. Ex: rats with darker coats are less likely to be spotted by hawks so they survive longer than light coated ones, this genetic information is passed on so more rats can live and adapt to hawks hunting them

7. Define species abundance and species richness and use these definitions to explain how two communities with the same number of species can differ in species diversity.

Species abundance is the amount of a species in a particular area. Species richness is the amount of different species in the same area.

8. Compare and contrast a food web vs a food chain.

Food chain tells the what animals are predators and prey in a specific area. A food web shows how nutrients flow within the system. A food web shows multiple food chains put together.

9. A typical food web in a grassland ecosystem could consist of five trophic levels –
grasses, mice, snakes, racoons, and bobcats.
a. Assuming there is a top-down control of the ecosystem, argue how you would
expect the grass biomass to change if bobcats are added to the system.

If bobcats are added to the system, then the population of the other trophic levels will change as well. The racoons will decrease, the snakes will increase, the mice will decrease, and the grasses will increase. The increased biomass of the bobcats will make them need more racoons to eat as nutrients. Therefore, there are less rancoons to eat the snakes, so more snakes will survive.

b. Explain what you would expect to happen if there is bottom up control of the
ecosystem if bobcats are added to the system.

If the ecosystem is bottom up control, then there would little to no change on the rest of the ecosystem. A bottom up ecosystem is dependent on the primary producers for the production of biomass. The increase of an apex predator will not affect the population sizes of other species.

10. Explain why high levels or very low levels of disturbance lead to reduced species
diversity.

Low levels of disturbance lead to reduced species diversity because the species will not be affected and limited. Disturbances eliminate organisms that cannot adapt. This lowers the population size of species and creates room for organisms to grow and evolve. If there is a low disturbance, then the species will change very little. Few organisms will die off and there will be no change in population size.

11. Outline how early species facilitate the arrival of other species during (secondary)
ecological succession.

Early species prep for the arrival of other species by altering the soil composition, creating proper primary producers to sustain life, and creating microclimates.

12. Compare and contrast the concepts of an ecological niches and an ecological role.

ecological niche" refers to the specific position or "role" a species occupies within an ecosystem, encompassing all its interactions with the environment, including its food sources, habitat, and relationships with other organisms, while "ecological role" simply describes the function or activity that a species performs within that ecosystem, focusing more on its contribution to the community dynamics

ecological role - the role of an organism, only worry about its personal function not related to other organisms

ecological niche - the job of an organism in an ecosystem related to other organisms(broader than the role), food and where it lives

13. Make connections to ecosystem ecology:
a. Identify categories of ecological roles based on the importance of an organism in structuring an ecosystem and increasing/maintaining the diversity and functioning of an ecosystem, and describe an example in each category.

primary producers - plants, transfer solar energy into energy that can be translated into the system as usable energy

primary consumers - rabbits, eat the primary producers

decomposers - break down feces and dead matter to recycle nutreints back into the soil for primary producers

keystone species - small population but large impact, usually predator

ecosystem engineers - modify/improve the habitat for a better quality ecosystem

structural species - ex: coral reef, create habitat of structural improvements to the ecosystem,

b. Identify categories of ecological roles based on trophic roles (metabolism) and
how they contribute to maintaining biodiversity and ecosystem functioning.

primary producers/primary consumers/decomposers

primary producers create food resources for a variety of primary consumers, decomposers support life of many primary producers

14. Make a connection to population ecology:
a. Argue whether you would expect to find r-selected species at early or late stages
of ecological succession.

I would expect to find r-selected species at the early stages of ecological succession because their traits allow them to survive well early on. They have a low maturity age, fast and high levels of reproduction. This is important to get a population started in the early stages of ecological succession because they can adapt well to limited conditions with not much biodiversity yet.

b. Argue whether you would expect to find K-selected species at early or late
stages of ecological succession.

I would expect to find K-selected species late in the stages of ecological succession because they have a later reproduction rate. They need to live longer to reproduce. They also only have a few offspring. If the species is able to survive with few offspring, it needs an environment that is more established with diversity.

15. As you study two closely related predatory insect species, the two-spot and the three-
spot avenger beetles, you notice that each species seeks prey at night when present in
an area where the other beetle species is absent. However, where their ranges overlap,
the two-spot avenger beetle hunts at night and the three-spot hunts in the morning.
When you bring them into the laboratory and isolate the two different species, you
discover that the offspring of both species are nocturnal.
a. Argue whether this is an example of character displacement or resource
partitioning.

"character displacement" - evolutionary change in a trait of a species, causing them to become more distinct from another similar species when they co-exist in the same environment

"resource partitioning" - broader ecological phenomenon where different species within a community utilize different aspects of a shared resource to minimize competition, often leading to the evolution of specialized traits that facilitate this partitioning. 

This is an example of resouce partitioning because the two similar species adapt to be around the other species. They adopt traits so that they can coexist. One insect begins to eat in the morning so the other insect can eat at night to minimize competition. The change that causes this alter is the resource partitioning, The resource partitioning is the cause of the species needing a change its habits in order to survive.

b. Depending on whether your decided that this is character displacement or
resource partitioning, modify this scenario to describe what it would look like if it
were the opposite scenario.

If it was character displacement, the insects would have adapted a mechanism to eat different bug so the insects don’t have to be shared with the other birds. Character displacement is the physical change of an organisms to better suit a niche so they limit competiton.

16. Argue whether more diverse communities are more productive or more stable than less
diverse communities.

More diverse communities are more stable becuase they are not fighting over the same resources. If there is a disturbance, a diverse community is more likely to survive and sustain because they have a variety of ways to adapt and continue on the community. A less diverse community would get wiped out if their one food source went exstinct which would alter the entire community.

17. During our population ecology module we looked at the example of predatory-prey
interactions of hare and lynx causing a boom and bust cycle in their population
dynamics. Explain the pattern assuming a bottom-up vs a top-down control

If it was a bottom up control, boom and bust of hairs would provide more or less priamry poducers avaiable. If it is a top down control, the amount of lynx increase or decrease the amount of hares in a boom bust cycle.

4 ARG extra questions

1. Compare and contrast the concepts of an ecological role and an ecological niche.

An ecological role is the specific job an organism has. An ecological niche is how an organism fits into an ecosystem. This includes their role, environmental factors, and other biotic factor (other species interacting).

2. Compare and contrast the concepts of ecological roles and trophic roles.

Ecological role is the job of an organism. How an organism contributes to the ecosystem through its role or job. Trophic roles are how an organism obtains its energy. It explains where it got its energy and where it will get passed to. How it contributes to the flow of energy within a system.

3. Compare and contrast the concepts of trophic roles and trophic levels.

Trophic roles are how an organism contributes to the flow of energy within a system. Trophic levels are the distinct separations between primary producers, primary consumers, ect. It shows the difference in what animals consume others. It shows how energy is cycled through organisms in a system.

4. Compare and contrast food chains and food webs.

Food chains show how organisms are organized into food sources. The primary producers are at the bottom while the apex predators are at the top. The food chains show which organisms eat which other organisms. Food webs are food chains linked together. They explain how an ecosystem’s flow of energy works. The energy is connected from apex predators to decomposers. The web shows how the nutrients of each organism is recycled back into the system.

5. Compare and contrast top-down vs bottom-up control of an ecosystem.

Top down control is when the primary producers of an ecosystem control the bioavaibalility of the ecosystem. If there are more primary producers, the rest of the ecosystem will flourish. If there are less primary producers, the rest of the ecosystem will suffer and not be as dense.

6. Draw a simple diagram listing major trophic roles depicting energy flow and nutrient cycling in an ecosystem. Use this diagram to explain (in words) why the transfer of energy is referred to as “energy flow” which the transfer of nutrients between these groups is referred to as “nutrient cycling”.
7. Review case studies for ecological roles.
8. Review case studies for ecosystem processes, trophic cascades etc.
9. Explain how ecologists can experimentally determine the factor that limits primary
production in an ecosystem.

ecologists can determine the factor that limits primary production by removing certain factors. They can relocate the plant to a different area. Or protect it from predators, or change the pH of the soil.

sunlight→plants→GPP (growth primary production 1%): total amount of solar enegry converted into primary production, 1,500,000 kcal/m2/year x 1% =0.01 15,000 kcal/m2 →NPP (net priamry production, total amount of energy that consumers can gain after primary producers do cellular respiration)

GPP -Ra 40-50% 15,000 - (15,000 × 0.5) =-7,500 kcal/m2/year →primary consumers → 10% rule lose energy to consumption, 750 kcal/m2/year respiration rate, and if they do not consume entire organism or feces, goes into biomass and available to →secondary consumers ASK TUDOR TOMORROW!!

ask O’leary

ask about questions 14-19 on last ARG and how much of it we need to know

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