Answer:
The simultaneous effect of a predator population on a prey population and a prey population on a predator population over time.
Explanation:
The mathematical models of Lotka-Volterra equations explain the existing interaction between species in which prey and predator influence and affect each other. The model follows a few assumptions,
- The ecosystem is isolated and closed. There is no migration.
- The whole individuals are reproductively equivalent.
- In the absence of the predator, prey shows an exponential growth rate. The prey is in the ideal environment.
- When there is no prey, the predator population decreases exponentially because of the lack of food. The predator environment is ideal, but it is limited by prey density.
- The predation rate is proportional to the encounters rate, which also depends on density.
- The predators affect the prey populations, inducing its decrease proportionally to the number of prey and predators present.
- The prey population also influences the predator population proportionally to the number of encounters between the two species.
In these equations, the variable D is the number of predators, and P the number of prey items.
The parameters are always constant:
• r1: prey growth rate.
• a1: predator hunting success.
• r2: predator growth rate.
• a2: the success of the predator in hunting and feeding.
In nature, many factors affect interactions, such as dense-dependent factors and dense-independent factors. Also, in reality, there are stochastic factors. Stochasticity refers to the variability in the system involving those factors that are affecting or influencing population growth. Stochasticity might be related to good years and bad years for population growth.
In real situations, the compliance of the whole assumption does not occur. The previously mentioned constants might vary, constantly changing the interaction between the predator and the prey. These parameters change in different degrees, resulting in varying circumstances for both species.
"D: A new gene, which codes for the protein that can repair defective genes, is introduced."
Explanation: <span>Gene therapy is an experimental technique that uses genes to treat or prevent disease. In the future, this technique may allow doctors to treat a disorder by inserting a gene into a patient’s cells instead of using drugs or surgery.</span>
The cell membrane is semipermeable (or selectively permeable). It is made of a phospholipid bilayer, along with other various lipids, proteins, and carbohydrates.
Answer:
A
Explanation:
The components of salt water are chemically combined together and looks throughout, forming a homogeneous mixture.
Some important elements that are required by a plant for proper growth, but were not accounted in the experimentation of Jan van Helmont are the nutrients from atmosphere such as carbon dioxide (CO2) and light.
In his famous experiment, Van Helmont planted willow shoots in a soil container and calculated the plant mass after five years. The tree gained great amount of mass but the soil didn’t lose much mass. He concluded that the extra mass of the plant had come from soil as well as water used for watering the plant.
Van Helmont clearly missed the importance of elements from atmosphere such as CO2 and light. A plant actually derives most of its energy from CO2 and light through photosynthesis, but only some of its energy from the soil.
Although, soil is important as it provides useful mineral to the plants like Nitrogen and Potassium. But, minerals do not represent major part of the plant mass. They are essential for constant development but they do not provide energy to plant. As we know, energy is made when CO2 and water combine to form carbohydrates and sugars. So it might sound surprising but the truth is that major part of plant mass is due to stored sugars. These sugars are eventually used by plant for general metabolic processes.
