The cow, which is a herbivore, affects the plant population in a community. When herbivores consume plants, this event triggers a decline in the plant’s population size and distribution.

a. cow

If organisms are unable to adapt to an environment that is outside of their range of tolerance, the likelihood of them dying and failing to reproduce is quite high.

b. The organisms fail to reproduce.

In an ecosystem, the term habitat refers to the place where the living organisms dwell. It is described as an area where the physical (abiotic) and biological (biotic) conditions of an environment affect the organisms living in it. The way plants and animals behave and look makes them suited to their habitats.

On the other hand, the term niche is defined as the role of an organism in the ecosystem. It can be compared to a person’s occupation. In an organism’s habitat, abiotic factors, biotic factors, and food web are all included in determining the role of a species in the ecosystem.

The competitive exclusion principle explains the no two species can have the same niche in the same habitat; hence, each species eat different food types and they obtain it in various ways. In the case of the two insectivorous birds living in the same tree, their diet consists of insects but they actually forage different types of insects. Some birds feed on big insects that they find on the ground, while some birds look for smaller insects. For example, the diet of a garden warbler consists of small insects, such as bugs and flies, and even spiders. On the other hand, a yellow-breasted chat hunt for medium-sized insects such as grasshoppers, beetles, and moths. Occasionally, this bird also feeds on some berries.

Commensalism is similar to a good friend helping you without asking for anything in return. This type of relationship happens when an organism is helped by another organism, but the other is neither harmed nor benefited. On the other hand, both organisms depend and benefit on each other in mutualism. It can be compared to a give and take relationship between individuals.

According to the competitive exclusion principle, when two species that are competing for the same resources, the stronger species outcompete the weaker ones. This is the reason why no two species can have the same niche in the same habitat; hence, each species eat different food types and they obtain it in various ways. For example, bird species have different types of beaks that is suited for their diet and niches. Carnivorous birds, such as owls and hawks, have sharp, hooked beaks which enable them to tear the flesh of the prey. On the other hand, fruit-and-nut eating birds, such as robins and blue jays, have powerful beaks that have a sharp hook at the tip to help them peel the skin of fruits and smash the nuts.

Parasitism is a relationship characterized by an organism that lives on another organism to get its nutrients and causes harm to the other. In other words, a parasite is a freeloader that gives nothing in return. This is the only symbiotic relationship which causes harm to the host. Unlike in parasitism, mutualism and commensalism cause no harm to any of the organisms involved in the relationship.

d,a,c,b

A is incorrect because keystone species refer to the species that perform a special and unique role in the ecosystem.

B is incorrect because climax species refer to the species that remain stable in a habitat that is undisturbed.

C is incorrect. Primary producers or autotrophs harness energy to perform either photosynthesis or chemosynthesis in order to make their own food.

D is correct. The first species to occupy a barren area that has no existing community due to volcanic explosions and retreating glaciers are called pioneer species.

d. pioneer species

If a lifeless or barren area contains a soil that is incapable of sustaining life due to a volcanic explosion or retreating glaciers, a primary succession will occur. Pioneer species inhabit this area. Examples of this include the formation of sand dunes, volcanic rocks, and new lands.

On the other hand, if an area contains a disturbed or damaged habitat that was caused by a natural disturbance or human activities, a secondary succession will take place. Examples of this succession occur in a forest cleared by a fire, and a wheat field that was destroyed by a hurricane. Oftentimes, once the plant and animal life in this area is restored, a climax community is formed.

When a natural disturbance or a human activity destroys an ecosystem, the existing community will undergo a secondary succession. In this succession, the remaining life-forms will restore the community. The regrowth will continue for years until the community becomes stable again. The end result is called a climax community.

The first species to occupy a barren area that has no existing community due to volcanic explosions and retreating glaciers are called pioneer species. In this case, the term pioneer refers to first colonizer or settler.

Ecological succession refers to the changes that take over in a particular ecosystem. The two major types of ecological succession include the following:

1. Primary Succession: Primary succession refers to the process of taking over a barren or undeveloped land that was exposed to volcanic explosions and retreating glaciers. This succession is similar to a situation when a person buys an empty lot.

2. Secondary Succession: This succession refers to the process of taking over a land where the residues from the previous ecosystem are still seen. This succession is similar to a situation when a person buys an old house.

The term diversity means variety. D is incorrect because generic diversity refers to the genetic variation that is present among species. It gives the sum of genetic information that is found in the genes of different species. Therefore, C is the correct answer. Biodiversity refers to the variety of organisms and other life forms that exist on a particular area.

c. biodiversity

The way the salt marsh ecosystem protects a coastal town from flooding is an example of flow buffering. In this particular situation, the marsh stores and slowly releases water to reduce flooding and coastal erosion.

b. buffering

Species diversity refers to the number of different species that are living in a particular location. On the other hand, genetic diversity is defined as the genetic variation that is present among species. It gives the sum or total amount of genetic information that is found in the genetic pool of different species.

An ecosystem service refers to the benefits that are given by the ecosystem for the purpose of maintaining the well-being of humans. Examples of ecosystem services include recycling of nutrients, purifying of water, producing foods, buffering the effects of weather, regulating pests, storing carbon, pollinating of crop plants, and maintaining the soil structure.

The term resilience refers to the ability of organisms to tolerate and to recover from all the disturbances and other changes in their surroundings. For an ecosystem to be resilient, it must be able to return to its normal patterns and processes after it was damaged by an ecological disturbance. One example is the way the Mulga woodlands in Australia can withstand shifts in its surroundings such as forest fires, herbivory, and rainfall. As a result, it can exist as a grassland or a shrubland, wherein either state is still resilient.

Bears are both classified under the same carnivorous descent. However, their diet varies depending on their environment. Polar bears have a carnivorous diet that consists of marine mammals, while grizzly bears are terrestrial omnivores. In this case, these two bears acquire distinct sets of microbial community in their digestive tract that are specific to their environment, diet, and lifestyle traits. This indicates that the microbiomes inside their digestive tracts are different from one another.

In a particular habitat, each species has their own ecological role or niche in order to live successfully with each other and to adapt to the conditions around them, particularly the availability of limited resources. In this case, if the same species have the need for the same limited resources, the stronger species will dominate over the weaker ones, thus the weaker species will become extinct. In order to maintain the balance in the ecosystem, the competitive exclusion principle is applied. This principle states that no two species can have the same niche in the same habitat; hence, each species eat different food types and they obtain it in various ways.

If a banana plant is exposed to conditions that are different from what they are used to have, its stability, function, and productivity will be affected. In this case, if the temperature is decreased by 1 degree Celsius every day, the banana plants in the second group would not be able to function properly because it is a plant that grows well at tropical and subtropical climates. If the temperature goes below 20 degrees Celsius, the plant will not stop growing. On the other hand, the banana plants in the first group would be able to function at its best since it is thriving at an ideal temperature of 30 degrees Celsius.

If a banana plant is exposed to conditions that are different from what they are used to have, its stability, function, and productivity will be affected. In this case, if the temperature is decreased by 1 degree Celsius every day, the banana plants in the second group would not be able to function properly because it is a plant that grows well at tropical and subtropical climates. If the temperature goes below 20 degrees Celsius, the plant will not stop growing. On the other hand, the banana plants in the first group would be able to function at its best since it is thriving at an ideal temperature of 30 degrees Celsius.

Here are the steps which can provide evidence that would help answer the question:

1. Observe the peanut plant for 10 days. Does the peanut plant, along with the presence of the bacteria, wither after a few days?
2. Check the appearance and the color of the leaves. Does the peanut plant, along with the presence of the bacteria, show signs of healthiness?
3. Check the soil condition including the nutrient levels in it.

The peanut plant contains nitrogen-fixing rhizobium bacteria in its roots, which help convert nitrogen gas into ammonia. The bacteria allows the plant to absorb nitrogen from the soil and reduce their dependence to nitrogen-rich fertilizers. The symbiosis between the peanut plant and the rhizobium bacteria indicates a mutualistic relationship.

If honey bees become extinct, their role in the ecosystem, which is pollination work, would be gone. Pollination is an important factor in creating and maintaining the habitats and species in the ecosystem by helping the reproduction of flowering plants. If bees are gone, many plant species would be gone and the animals eating those plants would be affected. Moreover, birds, badgers, and other animals that eat honey bees and their brood, as well as the nest and wax, are all affected.

As a solution, farmers should refrain from using pesticides. Instead, they should employ alternative non-toxic methods such as crop rotation. In this way, the infestation of pests would be reduced. In addition, planting trap crops are helpful in attracting the pests so that they would not infest the valuable crops.

Clearing the shrubland and the sand dune would cause a disturbance in the existing ecosystem. The carrying capacity of these areas would decline. As a result, many plant and animal species would be removed from their natural habitat. This would trigger their population to decline and to become extinct; hence, biodiversity and ecosystem services are threatened. Some of the services that are going to be affected include the cycle and movement of nutrients, mitigation of floods and drought, maintenance of soil and water quality, and regulation of climate conditions.

The community containing the tall grasses and young trees that was restored after the wildfire is a climax community. The tall grasses are not going to die because they are likely to maintain their stability unless the grassland is going to be destroyed by a natural disturbance.

Wetlands are considered as productive ecosystems due to its numerous benefits that include supporting diverse life-forms, preventing floods, improving the water quality by filtering waste and pollutants and providing a source of livelihood for people that live near the area.

One particular example of a wetland is a salt marsh. It houses a wide range of species such as herbs, grasses, shrubs, fishes, amphibians, mammals, and birds. It is also the shelter of migratory birds when they feed, breed, and nest during their breeding cycles. The interaction between the plant and animal species in this ecosystem allows it to deliver nutrients to its surrounding marine environment, and build climate resilience and coastal protection.

Wildebeests usually travel in large herds and graze during day and night at grassy plains. They are herbivores and consume grasses, leaves, and shoots. They are the food source of carnivorous animals in the African savanna, such as lions, cheetahs, wild dogs, and hyenas. On the other hand,

On the other hand, zebras are more active during the day. Their diet consists of a variety of grasses. Unlike wildebeests, zebras can consume shrubs, herbs, twigs and tree barks when the supplies of green grasses are low. They are usually seen in the open woodlands of Africa. They are also a reliable food source of lions, leopards, wild dogs, hyenas, cheetahs, and crocodiles.

The reason for this is because lies in the competitive exclusion principle, which explains that no two species can have the same niche in the same habitat; hence, each species eat different food types and they obtain it in various ways. This is the reason why zebras can also eat shrubs, herbs, twigs and tree barks because if they have the same diet as the wildebeests, the grasses in the African savanna would diminish at a faster rate.

In addition, both species have the same predators. If predators only consume the one type of species, their population would decline and there is a possibility of them getting extinct. Therefore, it makes sense if predators have different food sources in the grassy plains and the open woodlands.

The niches of wildebeests and zebras can be identified by looking at their habitat, diet, behavior, and predators. For example, the diet of wildebeests consists mainly of grasses and leaves; hence, they are likely to be seen where there are a lot of grasses and shrubs.

On the other hand, zebras consume a variety of grasses, herbs, and shrubs, including twigs and tree barks. This is the reason why they are likely seen in the open woodlands.

The predators of zebras and wildebeests also live in the same habitat. This makes sense because they ensure that the food sources of those herbivores do not diminish completely. Overall, their ecological roles are important in maintaining the health of their ecosystem.

The loss of biodiversity is caused by natural disturbances, such as wildfires and unusual weather patterns, and human activities that include the following:
a. Hunting – The demand for wildlife products continue to lessen the population of most animal and plant species. Hunting has caused endangerment of wild animals, and in worst cases, the extinction of species.
b. Altered habitats – This causes the habitat fragmentation. Habitat fragmentation means breaking or dividing the ecosystem into several pieces due to the developments happening in the environment.
c. Invasive species – These are the species that are introduced into a new environment in which their population can grow very quickly. This event causes the native species to be out-competed by the new species.
e. Pollution – It causes disruption in ecosystems and may eventually lead to death in most organisms and life forms. This factor also contributes to global warming and climate change.

Biodiversity can be recovered by eradicating the cause of the disappearance of plant and animal species in a particular area. Prohibiting the hunting of wild animals and illegal logging, restoring wetlands, planting more trees and plants and reducing the use of chemicals and plastics are some of the things that we can do to promote the recovery of biodiversity. Once the conditions of habitats are restored, reintroducing the plant or animal species into areas from which they are wiped out can be done.

When a catastrophe disturbs an ecosystem, vegetation is destroyed and the carrying capacity is reduced. This causes an impact on the food web, which causes it to become unbalanced. When this happens, some plant and animal species would go extinct. However, if the ecosystem is resilient enough, its ability to recover can help restore the ecosystem. This is when secondary succession takes place. After a few years, the vegetation will regrow and a climax community is established. The ecosystem remains stable until another disturbance takes place.

The soil is considered a microbiome because it has conditions that are different from the forest biome above it. For example, the atmospheric level and the amount of carbon and nitrogen are different in the soil when compared to the environment above it. It also contains a community of microorganisms which behave differently from the plant and animals species in the forest biome.

No, because the recovery of an old community after a major human-caused disturbance isn’t always guaranteed. There are particular situations wherein the regrowth of an original community is not possible. One example is the clearing and farming in a tropical rainforest. This often leads to changes in the soil and living conditions of that area. This change indicates that the organisms from the old community would not survive the new environment.

According to the model, the forest ecosystem started with a little amount of carbon and it has increased through time during the primary succession. Therefore, the rate of carbon storage in the forest has increased within 300 years.

The reason why the carbon storage in living plants, detritus, and soil begin at different times is due to the flow of carbon in the environment. Since all the vegetation and animals are killed by the disturbance, such as a volcanic eruption, the ecosystem contains a little amount of carbon from the volcanic deposits in the soil. From the soil, the carbon flows into the living organisms or pioneer species. Later on, they are replaced by plants. Eventually, the carbon storage flows into the detritus then back into the soil.

If the student uses the quadratic equation where a is positive, the curve would open upward and resemble a convex shape. On the other hand, if a is negative, the curve would open downward and resemble a concave shape. In this case, since the data in the graph shows an increasing rate of carbon storage over the years, the equation does not seem like a good fit to model the curve.

The graph below shows species that have a greater tolerance to a wider range of environmental variables. It is characterized by a curve with a wider band, which means that most species can still thrive in an environment that is exposed to either high or low amount of certain variables.

The graph below shows species that have a low tolerance range to the environmental variables. It is characterized by a curve with a narrower band. This illustrates that certain species can only be abundant in a specific environmental condition. They would die if they are exposed to an environmental factor that is either too little or too much.

The following graphs illustrate the tolerance of species to environmental variables. (Click to see the graph)

After a major ecological disturbance, such as volcanic eruptions and retreating glaciers, all the plants and animals are wiped out. This event results in a barren or undeveloped land with no plant life. In this type of environment, a primary succession takes place wherein the pioneer species, such as mosses, take over the land.

Eventually, the mosses cause the rocks to break and organic matter slowly accumulates. After this event, mosses are replaced by living plants like grasses. When the soil condition starts to normalize, a healthy plant and soil life will happen. In this stage, shrubs and trees will begin to grow. After several years, the softwood trees mature into hardwood trees. The ecosystem is likely to remain stable until a natural disturbance takes place.

Here is the procedure in which the students can use to identify the niche of pheasants:

1. Observe the feeding behavior of the bird. What does the pheasant eat? How do they obtain their food?
2. Observe the physical structure of the bird. What is the most distinguishable feature of the bird?
3. Observe the environment where the pheasants live. Do they live with other bird species?
4. Which organism feeds on pheasants?

Yes. Biodiversity plays a vital role in providing the benefits that are given by the ecosystem for the purpose of maintaining the well-being of humans. It is considered as the foundation of ecosystem services since it is mainly responsible for food production, nutrient cycling, soil formation, biochemical production, carbon storage, water purification, regulation of pests and diseases, pollination of crops, and climate regulation.

Let us take the biodiversity found in the wetlands as an example. Wetlands are considered as productive ecosystems due to its numerous benefits that include supporting diverse life-forms, preventing floods, improving the water quality by filtering waste and pollutants, and providing a source of livelihood for people that live near the area. Without the different life-forms that dwell in the wetlands, its ecosystem would not work efficiently. Without the microbes and plants, nutrient cycling and filtrating of waste and pollutants would not occur. If there are no animals, there would be no balance in the food web and in the entire ecosystem. Without biodiversity, the towns near the coast would have no access to clean water and food. They would have no protection against flooding and coastal erosion.