Population growth is based on the addition or removal of individuals in a particular area. The factors that affect population growth include birthrate, death rate, immigration, and emigration. Therefore, the answer is C.

c. emigration

When there are plenty of resources, the population will grow exponentially. This means that the growth rate increases at a constant rate.

Therefore, the factor that does not contribute to exponential growth is reduced resources.

d. reduced resources

An exponential growth is an increasing growth rate in which the people in a population reproduce at a constant rate due to a great number of resources. It produces a J-shaped curve in the graph. Therefore, the answer is D.

d. exponential

The term carrying capacity refers to the maximum population size of species which can be supported or sustained in a given area or ecosystem.

b. carrying capacity

Here are the three phases of a logistic growth:
a. Phase I: The population size grows very fast.
b. Phase II: The population growth slowly decreases due to limited resources.
c. Phase III: The population size stops growing since it has reached the carrying capacity.

Emigration is the act of moving out of an area with an intent to settle to a different place. On the other hand, immigration is an act of moving to a place occupied by an existing population which causes the population to increase. Both emigration and immigration cause a change in the population growth by adding people (immigration) or removing them (emigration) in a particular area.

The term population density refers to the quantity or the number of individual species or living beings per unit area. To determine the population density of an area, the number of people or population size is divided into the land area, which is either in the unit of square kilometers or square miles.

Geographic range refers to the spatial area that is inhabited by a population. In other words, this is where a certain type of species is found. The boundary or limit of an area is dependent on the species. Examples of a geographic range include the range of Sumatran orangutans in the North Sumatra province in Indonesia and the range of emperor penguins that are found in the coast of Antartica.

When a population increases to the point that it is larger than the carrying capacity, nature has its way of balancing the ecosystem. Since resources would become hard to find, the limiting factors, such as predation and diseases, would trigger the death rates to become high in order to control the growth and stabilize the population.

a. death rate may rise

Density-dependent means the population growth varies with the population density, which refers to the number of individual species or living beings per unit area. This type of limiting factor only controls the population growth if the density reaches the maximum level. In this event, small, scattered population is not entirely affected.

a. a small, scattered population

A density-independent limiting factor will affect a population without taking into consideration the current population size and population density in a certain area. Whether the population size has reached its carrying capacity or not, a density-independent limiting factor will always affect the population. Natural disasters and unusual weathers are involved in this type of limiting factor. Therefore, letter C is the best answer.

c. flood damage from a hurricane

If the limiting nutrient in a pond is increased, the productivity of the plant life in the pond gets better. Once the producers increase in number, the carrying capacity of the pond also increases; hence, more animals can be sustained by the pond ecosystem. This event will result in an increase in population growth.

Limiting factors, such as unusual weather patterns, global climate change, deforestation and invasion of natural environment or habitat of other species, can lead to species extinction. These factors can either destroy the habitat or reduce the carrying capacity of an ecosystem. If an area has an extremely low carrying capacity, the population can be wiped out; hence, an extinction will occur.

The rise and fall cycle of predation is a density-dependent limiting factor because if more numbers of prey are eaten by the predators, the prey’s population would decrease. On the other hand, if the population of the predator decrease, the population of the prey would increase.

Animal crowding triggers mortality in such a way that it causes unusual behavior from the animals. When animals are stressed, there is an overproduction of hormones in their body. As a result, they acquire diseases and exhibit abnormal sexual and social behaviors. For example, some chimpanzees who experience stress has been more fearful and often pulls away from the rest of the other chimpanzees. Some rabbits and deer die despite the adequate food supply in their ecosystem.

A density-independent limiting factor will affect a population without taking into consideration the current population size and population density in a certain area. Whether the population size has reached its carrying capacity or not, a density-independent limiting factor will always affect the population. Natural disasters and unusual weathers are involved in this type of limiting factor. One specific example of is the occurrence of flooding and landslides during a violent storm. Cutting down trees is mainly causing flooding and landslides since there are no longer trees that would help anchor the soil and absorb the excess water from the rain. As a result, some organisms would drown or some would get buried. This will lead to a decrease in the population size.

Demography is the study of statistics and human population by illustrating the birthrate, death rate, income rate, and the disease incidence rate.

b. demography

The industrial revolution resulted in an increase in the population size. During this time, production of foods and medicines were increased and the sanitation system has improved. These conditions have influenced the birthrate to increase.

c. grown more rapidly

Demographic transition shows the changes from high birthrates and death rates to low birthrates and death rates in a particular country. This transition happens when a pre-industrial economy turns into an industrialized economy. Therefore, the correct answer is A.

a. high birthrates and death rates to low birthrates and death rates

The demographic transition comprises of different stages. The first stage is characterized by high birth rates and death rates. On the other hand, the second stage occurs when the death rate begins to fall but the birthrates are still high. The final stage is characterized by low birth rates and death rate.

Therefore, if a country’s population grows exponentially, this means that it is still in the process of going through the initial stages of the demographic transition.

b. most countries have not yet completed the demographic transition

Thomas Malthus suggested the factors that limit the population growth include war, famine, disease and other density-dependent limiting factors. He believed that these factors regulate the human population. This study became the basis of Charles Darwin’s claim about natural selection.

Age-structure diagrams show the age and gender groups in a population. This allows demographers to predict the future population growth by determining the percentage of the female population. Since females are able to reproduce, demographers can predict the birth rate in the future. In addition, the percentage of children, teen, and adult population is also shown in an age-structure diagram. If there are more children and teens than adults, demographers may predict that the population will surely grow twice its size after a few decades or once the younger population matures.

When the population growth of the United States and Niger are both compared, the growth in Niger increases faster than in the United States. In Niger, the population consists of more children and teenager from ages 0 to 19 than the adults. In this case, the population will surely grow twice its size after a few decades or once the younger population matures.

On the other hand, the population in the United States consists of nearly equal numbers of people in the different age groups. This indicates a slow and steady population growth in the near future. In addition, the greatest percentage is in the working age group. This pattern is influenced by the immigrant population in the United States.

Studying the age structure diagram of the Florida panthers would help the scientist calculate and assess the future population data by determining the percentage of the female population and the percentage of the young and adult population. In this way, they can predict the future birth rate using the data about the female population and they can project the rate of population growth by comparing the percentage of the young population versus the adult population.

When the Asian carp were introduced into a new environment, their population grow very quickly due to the lack of predators or parasites that control them. Since no other species attack them, their mortality or death rate is very low, while their birth rate grows exponentially due to the abundance of resources in the environment. If this pattern continues, the native species in this environment could be out-competed by the new species and the existing ecosystem may be threatened or harmed.

In an entire population, if the birthrate exceeds the death rate, the population size would increase. If the adult population has a higher life expectancy, which decreases the death rate, but they reproduce a lesser number of children, the present population size would still increase. However, a fewer younger population would cause low fertility rates and birthrates in the next generation; hence, the population growth rate would eventually decrease.

Increasing the life expectancy of people can be met through improvements in housing, healthcare, and sanitation. Moreover, a decrease in birthrate is associated with population control laws, proper education, good lifestyle choices, and a high cost of living.

A. Fishing and hunting, population growth, invasive species, and urbanization: These icons are located in the human causes of global change. B. Populations, species ranges, species interaction, and extinction/diversification: These icons are placed under the measurable changes seen in the biosphere.

A. Fishing and hunting, population growth, invasive species, and urbanization: These icons are located in the human causes of global change.

B. Populations, species ranges, species interaction, and extinction/diversification: These icons are placed under the measurable changes seen in the biosphere.

The diet of sea otters consists of marine invertebrates, particularly sea urchins. In turn, sea urchins mainly feed on plant matter including kelp. In this case, hunting the sea otters would cause an increase in the population of sea urchins. If there are more sea urchins in the marine ecosystem, the demand for their food source would also increase; hence, the kelp forests would be endangered.

The predator-prey and herbivore-plant relationships, which occur between sea otters, sea urchins, and the kelp forests, help keep the balance in the ecosystem. These interactions regulate or control a population size by preventing some organisms from becoming excessively abundant.

Limiting factors which can affect the fishes in the lake includes the carrying capacity of the environment, predation, diseases and parasitism, competition, availability of food, nutrients, and space, and other biotic components such as temperature, sunlight, dissolved water, and pollutants.

In order to model these conditions, the aquarium must be able to hold around 100 fishes of different species, wherein some species would exhibit a predator-prey relationship. The availability of resources must be kept at a certain level that would trigger competition among the organisms.

To know how abiotic components would limit the population, the temperature of the water in the aquarium must be changed from time to time. The aquarium must be exposed to sunlight during the day. To model how nutrient levels in the water can affect the population, nitrogen and phosphorus can be added into the water to help in the growth of green algae. In turn, the concentration of dissolved oxygen can be influenced by the plant growth in the aquarium.

Diseases and parasitism are both categorized under the density-dependent limiting factors. This type of limiting factor is dependent on the density of a particular population. In this case, diseases and parasites spread faster when the population is very dense. The type of fungus that attacks the corn crop, wherein it uses the nutrients from the crops in order to survive; hence, the overall health and survival of crops are affected. This fungus would not do well in an environment that contains only a small population of corn crops.

Our planet has a carrying capacity of about 10 billion people in terms of the resources available. In the next 150 years, our population would continue to grow until we reach the Earth’s carrying capacity. Once we reach the maximum limit, a logistic growth will occur. This means that a decrease in the population growth will take place in order to stabilize the carrying capacity of our planet. This indicates that the human population size would be limited by several limiting factors. Density-dependent limiting factors include competition for resources, parasitism, diseases, and stress from overcrowding. On the other hand, density-independent limiting factors, such as unusual weather, and natural disasters, are likely to happen too.

The absence of natural predators that attack the moose would trigger an exponential growth in the moose population. An exponential growth is an increasing growth rate in which the species in a population reproduce at a constant rate due to a great number of resources and absence of predators. It produces a J-shaped curve in the graph.

Exponential growth occurs for only brief periods of time due to the land’s carrying capacity and the limiting factors that affect the population size. In the natural world, we do not have infinite resources, which is why there is only a maximum number of organisms that a particular area can support. Once the population reaches this number, limiting factors, such as availability of resources, competition, predation, diseases and parasitism, stress due to overcrowding and natural disasters, will cause the population to decline since the environment can no longer support or sustain the excess numbers. This type of growth is called a logistic growth.

The pattern shows an increasing world population from the year 1804 to 2050. It constantly grew over the years, which is an indication of an exponential growth. If the data on the table is plotted on a graph, it will produce a J-shaped curve.

According to the table, the population worldwide continues to increase over the years due to the plentiful resources in the environment and industrialization. This pattern indicates a steady growth in the world population. However, once our planet reaches its carrying capacity or limit, the population would begin to decline. During this time, a logistic growth will take place.

The answer is no. This event is unlikely to happen. Since the population is close to the Earth’s carrying capacity, the resources would be almost depleted and this would trigger competition for food, water, and space. Therefore, the population would show a logistic growth and start to decline after 2050.

The rabbit’s population has a rise-and-fall cycle from the year 1927 to 2007. During the mid-1950s, the myxoma virus, which caused myxomatosis, has effectively reduced the rabbit population. The remaining population was able to adapt and recover.

In the year 1970, the rabbit population peaked again. This led for another control measure to be introduced. During this time, rabbit fleas caused the population to decline.

After several years, rabbits developed a resistance against this disease and begin to multiply rapidly. To stop the population growth, RHD is introduced. RHD, which means rabbit hemorrhagic disease, is caused by a virus that affects rabbits. As a result, the population growth decreased.

After the control measure was introduced, there was a significant decrease in the population of the rabbits. However, since the remaining population of the rabbit was able to resist the virus and adapt to the situation, they were able to reproduce offspring; hence, it caused an increase in the population.

This event explains how a density-dependent limiting factor, such as diseases and parasitism, works in controlling the population growth. Once the population became dense, the disease has spread quickly and caused the population to decline dramatically. Since the rabbits are very low in number, the limiting factor does not strongly affect the small population anymore. This event has helped the population size to grow.

After the rabbits’ first exposure to myxoma virus in 1970, they have already developed a natural resistance against the original virus that was spread. In this case, if they are about to get exposed to the same kind of virus, they would have a high survival rate; hence, there would be no dramatic decrease in the population. However, if the rabbits are going to be exposed to a new strain of myxoma virus, the effect to them is lethal. As a result, their survival rate would be low and there would be a significant decrease in the population.

Demographic transition shows the changes from high birthrates and death rates to low birthrate and death rate in a particular country. The demographic transition comprises of different stages. The first stage is characterized by high birthrates and death rates. On the other hand, the second stage occurs when the death rate begins to fall but the birthrates are still high. The final stage is characterized by low birthrates and death rate.

Overall, this transition is said to be an indication that the economic development of a country and its population growth are related to each other. Most of us can observe that a country that is industrialized has high standards of living and a slow, steady population growth. On the other hand, a country that has not gone through the demographic transition has low standards of living and a population that grows at a faster rate.

To study and investigate the factors that limit the algae growth in a beaker that contains pond water, the following steps must be done:

1. Identify the biotic and abiotic factors that affect the growth of algae in an aquatic environment.

2. Determine the role of algae in the pond ecosystem’s food web.

3. Determine the relationship between the photosynthesis and the productivity of algae. Place one beaker in a place that is exposed to sunlight and put the other one in a room that is not exposed to sunlight. Leave the two beakers for five days and observe the changes in growth and color. Determine the algal growth in high light and low light.

4. Determine the relationship between the temperature and the productivity of algae. Place the three beakers in three rooms that have different temperatures: room temperature, 30 degrees Celsius and 5 degrees Celsius. After 5 days, observe the algal growth in the three beakers. Determine the algal growth in high temperature, low temperature, and room temperature. Observe the changes in terms of the color of the algae.

5. Determine the relationship between the nutrient level in the water and the productivity of algae. Prepare two beakers. In the first beaker, add a low concentration of nitrogen and phosphorus. On the second beaker, add a high concentration of nitrogen and phosphorus. After 5 days, observe the algal growth by comparing the color of the water inside the beaker.

6. Determine the relationship between the dissolved gases in the water and the productivity of algae. Prepare two beakers and cover one of them. Ensure that no air can penetrate inside the covered beaker. Place the two beakers at a windowsill, outside the room, or anywhere where they can be exposed to sunlight and air. After 5 days, observe the algal growth by comparing the color of the water inside the beaker.

To study and investigate the factors that limit the algae growth in a beaker that contains pond water, the following steps must be done: (Click to see explanation)

The limiting factors which affect the population size of plants and animals can also impact the human population. This is the reason why the patterns of plant and animal populations are also studied by scientists in order to have a better understanding of the human population. Knowing the history and patterns of a population can help the scientists know how population changes from time to time. In this way, they can predict the future population growth rate. Population data is also a useful tool in preventing the extinction of species and conserving the biodiversity in our planet.