IB Biology Chapter 4: Ecology

Photosynthesis is the correct answer because it is the process by which green plants and some other organisms convert light energy from the sun into chemical energy stored in the form of glucose or other organic compounds. This process involves the absorption of sunlight by chlorophyll in the plant's cells, which then uses this energy to combine carbon dioxide and water to produce glucose and oxygen. Therefore, photosynthesis is responsible for converting light energy into chemical energy in the form of carbon compounds.

Living organisms require a constant supply of chemical elements for various essential biological processes. These elements are necessary for building and maintaining cells, tissues, and organs, as well as for carrying out metabolic reactions. They are also involved in the synthesis of important molecules such as proteins, carbohydrates, and nucleic acids. Without a sufficient supply of chemical elements, living organisms would not be able to survive and function properly. Therefore, the statement "Living organisms need a supply of chemical elements" is true.

If the concentration of any greenhouse gas in the atmosphere changes, it will affect the greenhouse effect. The greenhouse effect is the process by which certain gases trap heat in the Earth's atmosphere, leading to an increase in global temperatures. When the concentration of greenhouse gases increases, such as carbon dioxide or methane, more heat is trapped, causing global temperatures to rise. Conversely, if the concentration of greenhouse gases decreases, less heat is trapped, resulting in a decrease in global temperatures. Therefore, it is true that changes in greenhouse gas concentrations can lead to changes in the greenhouse effect and subsequently affect global temperatures.

They are mixotrophic

An ecosystem refers to the community of organisms in a specific area and their interactions with the non-living environment. It includes both living organisms and abiotic factors such as soil, water, and climate. This definition highlights the interconnectedness and interdependence of all components within an ecosystem, emphasizing the relationships between organisms and their environment.

The correct answer is "A population is a group of organisms of the same species who live in the same area at the same time." This answer accurately defines a population as a group of organisms belonging to the same species that coexist in a specific geographic area. It highlights the key characteristics of a population, including the shared species identity, the spatial proximity of individuals within the same area, and the temporal aspect of individuals living at the same time.

Carbon dioxide is soluble in water and can react with water to form carbonic acid (H2CO3). This reaction occurs when carbon dioxide dissolves in water, and it results in the formation of carbonic acid, which is a weak acid. This is a reversible reaction, meaning that carbonic acid can also dissociate back into carbon dioxide and water. Therefore, carbonic acid is a possible product when carbon dioxide is dissolved in water.

The concentration of a gas depends on the rate at which it is released into the atmosphere and how long on average it remains there because both factors contribute to the accumulation of the gas in the atmosphere. If a gas is released into the atmosphere at a high rate and remains there for a long time, it will have a higher concentration. Conversely, if the release rate is low and the gas quickly dissipates, the concentration will be lower. Therefore, both the release rate and the residence time play a significant role in determining the concentration of a gas in the atmosphere.

A food chain is a sequence of organisms in an ecosystem, where each organism feeds on the previous one. This means that energy and nutrients are transferred from one organism to another as they consume each other. The correct answer accurately describes the concept of a food chain, emphasizing the flow of energy and the relationship between organisms in an ecosystem.

A community is formed by populations of different species living together and interacting with each other. This means that within a community, there are multiple species coexisting in the same area and engaging in various interactions such as competition, predation, and mutualism. These interactions shape the dynamics and structure of the community, influencing the abundance and distribution of species within it. A community is not limited to populations of the same species or different species living in different areas, as stated in the other options.

Cell respiration is the process by which cells break down glucose and other organic molecules to release energy in the form of ATP. It occurs in the mitochondria of cells and is essential for the survival and functioning of all living organisms. Through cell respiration, producers (such as plants) convert the energy stored in glucose into a usable form, which they can then use for growth, reproduction, and other metabolic activities. This process allows producers to release energy from the chemical compounds they obtain from their environment, enabling them to carry out life-sustaining processes.

Living organisms cannot convert heat to other forms of energy because of the second law of thermodynamics, which states that heat tends to disperse and become less concentrated. This means that heat energy cannot be completely converted into other forms of energy, such as mechanical or electrical energy, without the input of additional energy. While living organisms can use heat energy from their environment to perform certain functions, they cannot convert it into other forms of energy without the use of external energy sources. Therefore, the statement is true.

Unicellular consumers are single-celled organisms that take in food by endocytosis, which is the process of engulfing food particles into their cell membrane. Once inside the cell, the food is digested inside vacuoles. On the other hand, multicellular consumers, which are organisms made up of multiple cells, take food into their digestive system by swallowing it. The digestive system of multicellular consumers is responsible for breaking down the food and extracting nutrients for energy. Therefore, the correct answer is endocytosis; digestive system.

Species are groups of organisms that can potentially interbreed to produce fertile offspring. This definition emphasizes the reproductive compatibility within a group of organisms. It highlights the importance of successful reproduction in defining a species, as the ability to produce fertile offspring is a key characteristic that distinguishes one species from another. This definition also acknowledges that interbreeding is not always guaranteed, but the potential for successful reproduction is present.

A pool refers to a reserve of an element, which can exist in both organic and inorganic forms. This means that the pool can contain the element in its natural state or in a compound with other elements. The term "pool" does not specify the composition of the element, allowing for both organic and inorganic forms to be included in the reserve.

Autotrophic organisms are able to synthesize their own carbon compounds using carbon dioxide and other simple substances. This process is known as photosynthesis, where autotrophs convert sunlight into chemical energy. Autotrophs play a crucial role in the food chain as they are able to produce their own food, serving as a source of energy for other organisms. The variations in capitalization (autotrophic vs Autotrophic) and plural form (autotrophs vs Autotrophs) do not affect the meaning of the term, as they all refer to organisms that possess this ability.

Archaeans carry out methanogenesis in anaerobic environments. Methanogenesis is a process in which methane gas is produced by microorganisms. Anaerobic environments lack oxygen, which is necessary for the survival of many organisms. Archaeans are known to thrive in extreme environments, including anaerobic conditions, where they can produce methane as a byproduct of their metabolism. Therefore, anaerobic environments provide the ideal conditions for Archaeans to carry out methanogenesis.

Limestone rock is formed primarily of calcium carbonate. The variations in spelling in the answer options are likely due to typographical errors or mistakes. The correct spelling is "calcium carbonate."

The products of complete combustion are carbon dioxide and water. Complete combustion occurs when a fuel is burned in an environment with sufficient oxygen. During this process, the fuel molecules react with oxygen molecules to produce carbon dioxide and water vapor. Methane and oxygen are not products of complete combustion, but rather the reactants involved in the combustion reaction.

Saprotrophs are heterotrophs that obtain organic nutrients from dead organic matter by external digestion

The statement is false. When the null hypothesis is rejected, it does not automatically mean that the alternative hypothesis is true. Rejecting the null hypothesis only suggests that there is sufficient evidence to support the alternative hypothesis, but it does not prove it to be true. Other factors such as sample size, statistical power, and the possibility of Type I or Type II errors should be considered before making any conclusions about the alternative hypothesis.

The three requirements for sustainability in ecosystems are nutrient availability, detoxification of waste products, and energy availability. Nutrients are essential for the growth and survival of organisms in an ecosystem, as they provide the necessary elements for biological processes. Detoxification of waste products is important to maintain a healthy environment, as it prevents the accumulation of harmful substances. Energy availability is crucial for sustaining life in an ecosystem, as it powers various biological activities. These three requirements work together to ensure the long-term stability and productivity of ecosystems.

Consumers are organisms that obtain energy by consuming other living organisms. They do this through the process of ingestion, which involves taking in food and nutrients into their bodies. Ingestion is the correct answer because it accurately describes how consumers feed on living organisms.

Autotrophs are organisms that can produce their own food using energy from the sun or inorganic substances. They have the ability to absorb carbon dioxide from the atmosphere during the process of photosynthesis. This absorption of carbon dioxide by autotrophs leads to a decrease in the concentration of carbon dioxide in the atmosphere. Therefore, the correct answer is "reduces" or "Reduces" or "reduce" or "Reduce".

Carbon dioxide affects the pH of water because when it dissolves in water, it forms carbonic acid, which lowers the pH. It also affects photosynthesis rates as it is a necessary component for plants to undergo photosynthesis. Additionally, carbon dioxide can impact the concentration of other greenhouse gases as it is a major contributor to the greenhouse effect. However, it does not directly affect radiation from the sun.

Oxidation reactions are exothermic, meaning they release energy. This energy is then used in endothermic reactions to make ATP.

Detrivores -ingest- dead organic matter and then -digest- it internally and absorb the products of -digestion-

When carbonate ion concentrations drop, it becomes more difficult for reef-building corals to absorb them to make their skeletons. This is because carbonate ions are essential for the formation of coral skeletons. If the concentration of these ions decreases, corals have a harder time incorporating them into their skeletal structures, making the process more difficult for them.

Aerobic cell respiration is a process that occurs in cells to produce energy in the presence of oxygen. Saprotrophs, non-photosynthetic cells in producers, and animal cells all carry out aerobic cell respiration. Saprotrophs are organisms that obtain nutrients from decaying organic matter and carry out aerobic respiration to break down the organic material and release energy. Non-photosynthetic cells in producers, such as the root cells of plants, also undergo aerobic respiration to generate energy. Animal cells, including those in humans and other animals, rely on aerobic respiration to produce energy for their cellular processes.

Industrialization and burning fossil fuels are major factors contributing to changes in atmospheric carbon dioxide concentrations. Industrialization involves the growth of industries and increased production, which leads to higher emissions of carbon dioxide. Burning fossil fuels, such as coal, oil, and natural gas, releases large amounts of carbon dioxide into the atmosphere. These activities have significantly increased carbon dioxide levels in the atmosphere, contributing to global warming and climate change.

Peat forms when organic matter is not fully decomposed, not decomposed, or not completely decomposed due to anaerobic conditions in waterlogged soils. In such conditions, the lack of oxygen slows down the decomposition process, allowing partially decomposed organic matter to accumulate over time and form peat.

The expected frequency is calculated by multiplying the row total and column total and dividing it by the grand total. In this case, the row total for "Species A present" is 66 and the column total for "Species B present" is 64. Therefore, the expected frequency for this cell is (66 x 64) / 100 = 42.24.

Water vapor is formed through the process of evaporation, which occurs when liquid water changes into a gas state due to heat. This process primarily takes place in the oceans, where the sun's energy causes the water to evaporate. Additionally, plants release water vapor through a process called transpiration, in which moisture is released from their leaves. On the other hand, water vapor is removed from the atmosphere through precipitation, such as rainfall and snowfall. When the water vapor in the atmosphere cools and condenses, it forms liquid or solid particles that fall back to the Earth's surface as rain or snow, effectively removing the water vapor from the atmosphere.

The question is asking for three forms of descriptive statistics. The given answer includes six examples: mean, mode, median, standard deviation, range, and error bars. Descriptive statistics are used to summarize and describe data, and these six examples are commonly used to provide information about different aspects of a dataset. The mean represents the average value, the mode represents the most frequently occurring value, and the median represents the middle value. Standard deviation measures the spread of the data, range represents the difference between the maximum and minimum values, and error bars are used to indicate variability or uncertainty in the data.

Methane molecules released into the atmosphere persist for an average of 12 years because they undergo natural oxidation in the stratosphere. This process causes the methane molecules to be broken down and converted into other compounds, reducing their concentration in the atmosphere. Therefore, atmospheric concentrations of methane are not high due to this natural oxidation process.

The answer explains that humans are emitting carbon dioxide through the burning of fossil fuels, and there is strong evidence that carbon dioxide causes warming. Therefore, the claim that human activities are not causing climate change is not supported by the evidence. The answer emphasizes the connection between human activities, carbon dioxide emissions, and the resulting warming, concluding that humans are indeed causing climate change.

Energy losses between trophic levels in a food chain occur due to various factors such as incomplete digestion, heat loss, and energy used for cellular activities. As energy is transferred from one trophic level to the next, only a fraction of it is incorporated into the biomass of the consuming organisms. This means that the energy available for the next trophic level is reduced, resulting in a decrease in biomass and limited length of food chains. Additionally, not all organisms in a trophic level are entirely consumed by the next trophic level, further contributing to the restriction of food chain length.

Coal is formed when deposits of peat, which is partially decomposed plant matter, are buried under other sediments. Over time, the peat is compressed and heated, resulting in the formation of coal. On the other hand, oil and natural gas are formed in the mud at the bottom of seas and lakes. As more mud and sediments are deposited, the partially decomposed organic matter in the mud is also compressed and heated, leading to the formation of oil and natural gas. Therefore, the formation of coal, oil, and natural gas involves the burial, compression, and heating of organic matter over long periods of time.

Solar radiation, including longer-wavelength radiation, reaches the Earth's surface. A significant portion of this radiation is converted to heat. Around 70%-80% of the longer-wavelength radiation emitted by the Earth's surface is then captured by greenhouse gases. These greenhouse gases re-emit the energy, some of which is directed back towards the Earth. This process leads to global warming, as the increased concentration of greenhouse gases in the atmosphere traps more heat and raises the Earth's temperature.

An increase in global temperatures can lead to an increase in evaporation of water from the oceans. This increased evaporation can result in more rain, as the water vapor in the atmosphere condenses and falls back to the Earth's surface. Additionally, the warmer temperatures can contribute to the formation of more tropical storms and hurricanes. These storms are likely to be more frequent and more powerful due to the higher energy and moisture content in the atmosphere. Overall, the increase in evaporation, tropical storms, and hurricanes are all aspects of climate that can be influenced by a rise in global temperatures.