ISAT 320 Exam 1 texbook questions

Outline the wildebeest migration pattern and tie that together with rainfall patterns, the availability of nutritious grass, and the timing of when wildebeest give birth to their offspring.

In the northeast the nutrient levels are low but receive the highest rainfall and the southeast has the highest nutrient levels but low with rainfall so the wildebeest and othe animals will spend the wettest months in the southeast and then migrate northwest when in becomes dryer

2. What were Sinclair's three hypotheses for increases in buffalo and wildebeest abundance in the 1960s and 1970s? How did he test the predictions of each hypothesis, and what did he conclude based on each test?

Food: Hypothesised it was the food which had a correlation to the amount of rainfall-created exclosures and harvested veggies from the inside, positive correlation between rainfall and food availability, but since the rainfall frequency was average to prior years food didnt make sense.

Water:Hypothesised it was the food which had a correlation to the amount of rainfall-created exclosures and harvested veggies from the inside, positive correlation between rainfall and food availability, but since the rainfall frequency was average to prior years food didnt make sense.

Disease:Disease—-rinderpest release hypothesis, measles -like virus said this virus should have declined with the increase of wildebeest and buffalo

No correlation between them-arguing that serengeti mammals were not susceptible to rinderpest

Or increased survival rate in juviniles

Give two examples of community-level biotic interactions discussed in this chapter. In what ways may abiotic factors be linked to each example?

Fire and relation to tree density, more fire less dense trees but also other orgaisms like elephants and giraffes could be affecting the trees-they were able to determine that elephants were eating many of the small trees, in the case of seringetic it can either be grassland or open woodland to be a grassland there must be high fire rates and lots of elephants and the opposite for woodland

4. What are the levels of the biological hierarchy most often considered by ecologists? Give an example of a question that an ecologist might ask that pertains to each level of the hierarchy that you cited.

Organism populations communities ecosystems landscapes(savanna)

In what way might and organism be implicated by its landscape how and how does that impact affect cohabitating organisms

5. What are three general questions that ecologists ask?

How do organisms interact with their environment and with each other?

. How do ecosystems function and respond to changes?

What are the patterns of distribution and abundance of organisms?

Which terestrial and aquatic biomes have the greatest species richness? How are these to biomes similar to each other, and how do they differ?

Coral reefs and tropical rainforests-high levels of species diversity but have low nutrient levels(rainforests in nutrient-poor soils and coral reefs in nutrient-poor waters), both very productive and highly effected by deforestation, climate change, pollution, and habitat destruction.

Tropical rainforest have photosynthetic vasular plants the whereas corals host algae that photosynthesis which provide energy to the corals

How does climate influence the distribution and structure of Earth's terrestrial biomes?

More tolerant plants and animal species will make up the biomes that are subjected to constantly changing climates and make up those systems. The temperature and percipitation will determine what plants and animals will be in a certain location as well as the richness of species in that area and biome productivity

Describe five different ways in which nutrients influence the structure and functioning of terrestrial or aquatic biomes.

influences the presence of important photosynthetic vascular and marine plants that resupply the biome with nutrients and their diversity. In addition to this more vegetation means more habitats for animals to live which generally increases biodiversity in that biome.

More nutrients aids in the natural succession in a biome and can help improve the soil quality due to decomposition,

Too much nutrients can lead to algae blooms in aquatic biomes which can negatively impact its biodiversity and lead to dead zones

It affects the species richness, soil quality,

What factors do Ellis and Ramankutty identify as defining anthropogenic biomes? Do you believe their definition of biomes is useful? Why or why not?

Human population, land use, land cover-dense settlements,villagesm croplands,rangelands, inhabited forests and uninhabited wildands

Humans may impact nutrient presence by adding fertilizers, cutting down trees leading to more runoff, or implementing irrigation practices to improve moisture, or the impact of air pollution and it making the biomes more acidic

In trying to access biomes it would be important to factor in humans as we are a part of those biomes and have a direct impact, including us will lead to a more in depth understanding of how we are impacting our earth and its subsystems

4 main reservoirs for carbon

Carbonate containitn rocks fossil

Dissolved in surface and ocean water

Atmosphere mainly CO2

Plants and animals where carbon atoms are combines with hydrogen, oxygen and nitrogen

Most of the world's carnon is stored in carbonate rocks and deep waters

Why did people embrace legislation to protect stratospheric ozone, but resist legislation to mitigate climate change?

The "ozone hole" was a tangible and visible phenomenon, making it easier for the public and policymakers to understand the problem and the consequences (e.g., increased skin cancer risks due to UV radiation).

Climate Change: Climate change is a more complex issue with numerous contributing factors (fossil fuel use, deforestation, agriculture) and varied impacts (global temperature rise, extreme weather, sea level rise). The complexity makes it harder for the public to grasp, and misinformation or skepticism about the science has hindered broad consensus.

What are the biggest sources and biggest sinks of atmospheric carbon? Which sources and sinks have experienced the greatest percent change since 1750?

Fossil Fuel Combustion:

Land Use Changes (Deforestation):

oceans: Oceans are the largest carbon sink, absorbing around 25-30% of anthropogenic CO%E2%82%82 emissions. CO%E2%82%82 dissolves in seawater and is used by marine organisms or stored as dissolved carbon.

Terrestrial Biosphere (Forests, Vegetation, and Soils): Forests and soils absorb CO₂ through photosynthesis, acting as a natural carbon sink. Growing forests and reforestation efforts can increase this capacity.

distinguish between radiative forcing and global warming potential. Which greenhouse gas has greatest radiative forcing, and which has greatest global warming potential?

Radiative Forcing quantifies how much a gas or factor affects the Earth's energy balance directly.

Global Warming Potential compares the heat-trapping ability of a gas to that of CO₂ over a specified time.

CO₂ has the greatest radiative forcing, while SF₆ has the highest GWP.

Describe how directional selection has caused rapid evolution in threespine sticklebacks, pathogenic bacteria, and Darwin's finches.

Tradeoff in Armor Reduction: In freshwater environments, sticklebacks evolved to have reduced armor and fewer spines. While this makes them more vulnerable to predators, the tradeoff is that producing less armor requires fewer resources and increases their mobility

Tradeoff in Fitness: While antibiotic resistance allows bacteria to survive in environments with antibiotics, there are often fitness costs in environments without antibiotics. Resistance mutations can slow bacterial growth or decrease reproductive rates in drug-free environments.

finches with larger, stronger beaks were better able to crack open tough seeds, giving them a survival advantage.Tradeoff in Beak Size

What are the four major evolutionary processes? Which of these processes can (a) lead to adaptation, (b) increase genetic variation within a population, and (c) reduce the probability that speciation will occur?

Natural Selection

Genetic Drift

Gene Flow (Migration)

Mutation

Natural selection leads to adaptation

Mutation and Gene Flow can both increase genetic variation within a population.

Gene Flow can reduce the probability of speciation by mixing the genetic material of populations.

. Use the redback spider example to describe circumstances in which natural selection may tend to decrease the survival of individuals within a population. How does this tie in with the concept of fitness?

male spider getting eaten by the female, male's death increases the likelihood that the male's sperm will be used to fertilize the female's eggs.Female's Receptivity, Decreased survival of individuals, Resource Transfer:

What is an adaptive radiation and when is it most likely to occur?

Adaptive radiation is an evolutionary process in which a single ancestral species rapidly diversifies into a wide variety of forms to adapt to different environments or ecological niches.

Common Ancestry,Rapid Speciation,Ecological Opportunity:

most likley to occur

Colonization of New Environments, Mass Extinctions, Geographical Isolation:

According to (a) David Lack's and (b) Kenneth Petren et al's phylogenetic trees, which two species of Geospiza are most closely related? According to Lack's tree, which species is/are

Two Most Closely Related Species (According to Lack): In Lack's tree, Geospiza fortis (medium ground finch) and Geospiza fuliginosa (small ground finch) were often considered closely related based on their similar body size and beak shapes, which are adaptations to similar feeding behaviors.

focuses on morphological stuffshowing that species with different ecological niches (like ground and cactus finches) might be more closely related than previously thought.Geospiza fortis and Geospiza scandens are most closely related.

Petren focused more on molecular data,

Other Features in Lack's Tree: Lack's tree also showed a relatively close relationship between Geospiza magnirostris (large ground finch) and other ground finches due to their shared ground-feeding habits and robust beaks for seed-crushing.

Outline how researchers used different types of experimental approaches to test whether iron was a limiting resource in some ocean communities. What were strengths and weaknesses of each approach?

Bottle Experiments: Small-scale enclosed water samples are taken from the ocean and enriched with iron.pro:Controlled environment, easier to manipulate and observe.

con:Does not fully represent natural ocean conditions

Open Ocean Iron Fertilization Experiments: Researchers add iron directly to ocean patches and monitor the response of plankton and other organisms over time.

Strengths: Most realistic, studies the impact in real-time in the open ocean. Showed a significant increase in chlorophyll levels and a decrease in nitrate levels

Weaknesses: Logistically difficult, expensive, and potential environmental concerns regarding large-scale ecosystem manipulation.

Given its shortcomings, why is rubisco used as a key enzyme in the process of carbon fixation?

Essential for the Calvin Cycle

Adaptation and Support Mechanisms-Although Rubisco's oxygenase activity leads to photorespiration, plants have evolved mechanisms, like the C4 and CAM pathways, to minimize this inefficiency in certain environments.

No Better Alternative

Evolutionary History**: Rubisco evolved in an atmosphere with low oxygen levels, where its inefficiency in distinguishing between CO₂ and O₂ was not a significant problem.

. What are induced and constitutive defenses? How does the study by Schultz and Appel

(2004) show (a) the existence of induced defenses in oak trees, and (b) that predators on oak trees have evolved adaptations to counter these induced defenses?

Constitutive Defenses:

Constitutive defenses are always present in an organism, regardless of the level of threat. These defenses are "built-in" and maintained continuously as part of the organism's overall strategy for survival.

Induced defenses are only activated or increased in response to an attack or threat, such as herbivore feeding or predator presence. These defenses allow organisms to conserve energy by producing defensive mechanisms only when needed.

Schultz and Appel showed that when oak trees are attacked by herbivores (such as caterpillars), they increase their production of chemical defenses.

herbivores that feed on oak trees have evolved adaptations to overcome these induced defenses.

How may organisms respond to physiological challenges over different time scales? Give an example of each type of response.

Immidate: Fight-or-Flight Response:

Acclimitizatoin: Acclimatization to High Altitude:

Evolutionary Adaptations:Beak Shape in Darwin's Finches:

What factors influence thermal balance in terrestrial animals? How do these factors influence body temperature in camels and kangaroo rats? What adaptations do camels and kangaroo rats have that allow them to avoid overheating?

envionment temps, sun exposure, wind and humidity, behaviroral adaptations, physiological adaptations.

Fur Insulation: Their thick fur reflects sunlight and provides insulation, helping to maintain cooler body temperatures during the day.

Body Temperature Regulation: Camels can allow their body temperature to rise, which minimizes sweating and reduces water loss.

Kangaroo Rats

Nocturnal Behavior: Kangaroo rats are primarily nocturnal, allowing them to avoid the intense daytime heat by being active at night when temperatures are cooler.

Burrowing: They create burrows in the ground, which provide a cooler microhabitat and protection from extreme temperatures.

What factors influence thermal balance in plants from (a) cold climates and (b) from hot climates?

Low Temperatures: Plants must conserve heat and avoid freezing.

2. Snow Cover:Insulates plants but can also limit light.

3. Wind Exposure:Increases heat loss through convection.

- *Leaf Shape and Orientation:* Conical shapes (like those of conifer trees) minimize snow accumulation, reducing the risk of branch breakage.

- *Dark Pigmentation:* Dark-colored leaves can absorb more solar radiation, helping to maintain warmth.

Hot Climates

*Factors Influencing Thermal Balance:*

1. *High Temperatures:* Plants face risk of dehydration and heat stress.

2. *High Solar Radiation:* Intense sunlight can lead to overheating.

3. *Dry Winds:* Increase transpiration rates, leading to water loss.

Thick Cuticles: A waxy coating on leaves helps reduce water loss and reflect excess light.Stomatal Regulation:** Many plants in hot climates, like cacti, have stomata that open at night (CAM photosynthesis) to minimize water loss during the day.

- *Leaf Orientation:* Some plants orient their leaves to minimize sun exposure during peak heat.

How do marine animals confront the challenges of thermoregulation and osmoregulation?

Thermoregulation

Ectothermic Animals: Many marine animals, like fish, are ectothermic (cold-blooded), meaning their body temperature fluctuates with the surrounding water. They may seek out warmer or cooler waters to regulate their temperature.

endotherms:Insulating Blubber: Thick layers of fat help retain heat in cold waters.

Countercurrent Heat Exchange: Blood vessels are arranged so warm blood warms cooler blood returning from extremities, reducing heat loss.

Behavioral Adaptations:

Marine animals may migrate to different depths or latitudes to find optimal temperatures, or they may bask in sunlight at the surface.

saltwater animals:Drinking Sea Water: Many marine animals actively drink seawater and excrete excess salts through specialized cells in their gills or kidneys.

Freshwater Animals: Conversely, freshwater species (like some fish) are in a hypotonic environment and face the risk of taking in too much water. They adapt by:

Excreting Dilute Urine: They produce large volumes of dilute urine to eliminate excess water.

Absorbing Ions: Freshwater fish actively take up salts through their gills to maintain osmotic balance.

What water regulation challenges are faced by mature plants in dry and very moist environ-ments? What are some adaptations in plants from these environments?

challenges:Water Loss, Soil Moisture Depletion,

adaptations: thick cuticle(waxy coating), deep root systems, reduced leaf surface to decrease transpiration,

. What are some common features of tool use in humans and crows?

Problem-Solving Skills,. Selection and Modification of Tools,. Learning and Teaching

Explain Jerram Brown's (1964) model of territoriality. How did Ethan Pride's (2005) study of lemurs use the concepts underlying Brown's model? What did Pride's research reveal?

Model: territoriality should developewhen the benefits of territory exceed costs,Territoriality is a cost-benefit trade-off. It is maintained when the benefits (e.g., access to food or mates) outweigh the costs (e.g., energy spent defending the territory).

The model predicts that animals will defend territories only when it is economically feasible, meaning that the resources obtained are worth the energy and risk of defense.

Ethan Pride's study of lemurs used Brown's (1964) model to explain how lemurs balance the costs and benefits of territorial defense. By examining lemur behavior in different resource conditions, Pride demonstrated that territoriality is a dynamic and flexible strategy, shaped by the need to maximize resource access while minimizing defense costs, aligning with the principles of Brown's model

. How does dunnock behavior highlight the importance of resource distribution in the evolution of mating systems?

Resource Availability

Food Distribution: Dunnocks (Prunella modularis) often inhabit environments where food resources are unevenly distributed.

Mating Systems Variation

Monogamy vs. Polygyny vs. Polyandry:

Female Choice and Male Competition

Territoriality

Territorial Defense: Dunnocks often defend territories based on resource availability.

Flexible Mating Behavior

Adaptability: Dunnocks display flexible mating behaviors that adapt to changes in resource distribution. This adaptability suggests that mating systems can evolve rapidly in response to environmental changes, demonstrating a dynamic relationship between resource availability and reproductive strategies.

Distinguish between direct and indirect selection. Use examples to show how the concept of inclusive fitness has improved our understanding of the evolution of cooperative behavior.

Direct selection refers to the process where an individual's traits increase its own reproductive success. In a population of birds, larger beaks may be directly selected for if they allow individuals to access larger seeds that provide more energy. -more likely to survive

Indirect selection involves the benefits an individual gains from the reproductive success of its relatives.

Social Structures: Understanding inclusive fitness has helped explain the evolution of complex social structures, such as those seen in primates or ants, where individuals may sacrifice their own reproductive opportunities for the benefit of the group.

. Explain the Prisoner's Dilemma model. What is the simple solution to this dilemma for many species? What are more complex solutions to the Prisoner's Dilemma, and what are some characteristics of species most likely to use these complex solutions?

Cooperate with the other by remaining silent.

Defect by betraying the other and testifying against them.

The dilemma arises because, while mutual cooperation yields the best collective outcome, each individual has an incentive to defect for personal gain, leading to a worse outcome if both choose to defect.

reciprocal altruism, where individuals cooperate based on the expectation of future mutual cooperation. This approach can be effective in environments where individuals interact repeatedly. Tit-for-Tat Strategy: A common approach where an individual starts by cooperating and then mimics the previous action of the partner. If both individuals engage in this strategy, they can establish a stable cooperation over time.

species most likely:

High Sociality, Long Lifespans,Strong Kin Relationships

What life history traits do North Atlantic right whales have that make them unlikely candidates for quick recovery following protection? Why is it important for people to understand the relation between potential recovery rates and life history traits?

Right whales possess life history traits that make them unlikely to recover quickly after protection:

Long lifespan*: Right whales can live up to 70 years, meaning population turnover is slow.

- *Late sexual maturity*: Females don't reproduce until around 9-10 years old, delaying their contribution to population growth.

- *Low reproductive rate*: They have a long gestation period (about a year) and only give birth to a single calf every 3-5 years.

- *Parental investment*: High investment in each offspring through extended care, which limits the number of offspring produced.

What are two classification schemes devised by ecologists to distinguish between different groups of species. What are strengths and weaknesses of these approaches?

K Selection Theory**:

- *r-selected species*: Produce many offspring with low investment per offspring (e.g., insects). They thrive in unstable environments and prioritize reproduction.

- *K-selected species*: Produce fewer offspring with higher investment (e.g., elephants), more competitive in stable environments.

Explain in detail the relationship between number and size of offspring. Why does this relationship exist?

Many small offspring**: Organisms that produce many small offspring (e.g., fish) typically invest less in each one. Small offspring are more vulnerable to predation but allow for the spreading of risk across many individuals.

- *Fewer large offspring*: Organisms that produce fewer large offspring (e.g., mammals) invest more in each, increasing their chances of survival through parental care or better-developed defense mechanisms.

It arises from resource constraints. Parents have limited energy and must balance between producing many offspring or investing heavily in fewer offspring,

Describe two models explaining the evolution of semelparity in plants. What is the evidence supporting each model?

Plants accumulate resources over time and invest everything in one reproductive event when environmental conditions are favorable. This strategy reduces the risk of failed reproduction due to unfavorable conditions in multiple breeding events.

Bet-Hedging Model explains semelparity as an adaptation to unpredictable environments, where a single massive reproductive event maximizes survival chances.

Reproductive Effort Model explains semelparity as a response to high reproductive costs, where reproducing multiple times is inefficient or too risky.

What are three basic patterns of dispersion? Which is most common in natural populations (and why)? Give examples of each dispersion pattern in natural populations?

Clumped Dispersion

Description: In clumped dispersion, individuals are grouped in patches or clusters.

Uniform Dispersion

Description: In uniform dispersion, individuals are evenly spaced throughout an area.

Random Dispersion

Description: In random dispersion, individuals are distributed unpredictably and independently of one another.

2. Distinguish between dispersal and migration. Why might it be advantageous for a species to migrate? Why might it be disadvantageous?

Dispersal definition: Dispersal refers to the movement of individuals away from their place of origin or from one area to another. This movement can occur in various forms, such as seeds being carried by wind or animals moving to new territories

Advantages of Migration:

Resource Availability:,Breeding Opportunities, Avoiding Harsh Conditions:

Disadvantages of Migration:

Energy Costs:

Predation Risks:

Habitat Loss:

Navigation Challenges:

What factors influenced species distribution in (a) the Niagara Escarpment and in (b) kelp populations in nearshore habitat? How did the researchers identify these factors?

Desiduous side: Deep Soil richness, high nutrient presence, deep snow presence, lots of light. Where as the white cedars didnt have this as much likely do to them being shaded by the cliff side. Adjacent locations can have completely different effects, a distance of 5 m produces a totally different distribution

Uv radiation influenceing the species distribution-predicted that kelp species that lived closer to the surfacewould be more more immune to the toxic effects of UV radation -they tried to measure the depth to which uv and particularly uvb radiation would penetrate

How do nurse plants influence saguaro distribution? How does saguaro influence nurse plant distribution?

Microclimate Creation:

Nurse plants, such as mesquite (Prosopis spp.) or palo verde (Cercidium floridum), provide shade and reduce extreme temperature fluctuations.

Soil Moisture Retention:

The canopy of nurse plants helps retain soil moisture by reducing evaporation and promoting better water infiltration.-useful in arid climates

Protection from Herbivores:

Young saguaros are vulnerable to herbivores,

Influence of Saguaros on Nurse Plant Distribution

Soil Enrichment:

As saguaros grow, they drop organic matter

Water availability

Habitat modification

Seed dispersal

What are invasive species? Use the red fox study by Kinnear et al. (1998) to highlight a problem caused by invasive species

In 1845 20 red foxes were introduced to australia, preyed on smaller mammals- kinnear removed the foxes from 2 spots to test if they are invasive and wallaby population increased significantly and they concluded that the red foxes were important in limiting the wallaby population

Distinguish between a fundamental and realized niche. How did ecologists use the niche concept to make predictions of future distributions of rainbow smelt?

The fundamental niche refers to the full range of environmental conditions and resources that a species can theoretically occupy and utilize in the absence of competitors,

Realized Niche

Definition: The realized niche is the actual set of conditions and resources that a species occupies and utilizes in the presence of biotic interactions, such as competition, predation, and mutualism.

Conservation and Management,Evaluating Invasive PotentialModeling Climate Change Impacts:

Smelt migrate upriver to breed but w human introduction their range has increased are found in many different lakes in the US. scientists sampled these lakes-smelt are commonly found in deep large lakes , these lakes typically had lower phosphorus levels and game management also impacted these factors

Based on reading this chapter, list as many density independent and density-dependent factors as you can. Then discuss whether any of these factors could be both density-independent and density-dependent.

Density-Independent Factors:

Weather events (e.g., hurricanes, floods, droughts)

Natural disasters (e.g., wildfires, volcanic eruptions)

Pollution

Climate change

Density-Dependent Factors:

Competition for resources (food, space)

Predation

Disease and parasitism

Territoriality

Explain how human population growth rates are declining steadily, yet each year still has a large increase in the number of people added to the population.

Human population growth rates are declining due to several factors, including:

Increased access to education, particularly for women.

Greater availability of contraceptives.

Improved healthcare and reduced infant mortality rates.

population vs community vs ecosystem

Ecosphere: Global sum of all ecosystems, including abiotic and biotic components.

Community: Interaction of different species in a specific area.

Population: A group of individuals of the same species in a specific area.

3 essential parts of a system

elements, in connections, purpose/function

if an ecologist is measuring the primary production of an ecosystem what is being measured

chemical energy

what happens near the end of the meridional overturning circulation path

CO2 dense waters reach the tropics and the co2 becomes less soluble and is released into the atmosphere

Species diversity vs richness

diversity: a measure of how many species are present in a particular environment as well as relative abundance.

richness is the number of different species in a particular area

5 major soil forming factors

parent materials, climate, organisms, topography, time