Biology Questions: Chapter 13 Organisms And Populations

The term "sex ratio" refers to the number of females to males in a given population. It is a measure used to understand the balance between the two sexes in a population. This ratio is typically expressed as the number of females per thousand males. Therefore, "sex ratio" is the correct answer as it accurately represents the concept of the number of females to males per thousand individuals.

Population density refers to the number of individuals present per unit area at a given time. It is a measure of how crowded or concentrated the population is in a specific area. This metric is calculated by dividing the total population size by the total land area, providing an indication of the intensity of population distribution. Therefore, population density is the most appropriate term to describe the given scenario.

Mammals of colder climates generally have shorter ears and limbs to minimize heat loss. This is because ears and limbs have a large surface area, which increases the amount of heat that can be lost to the environment. By having shorter ears and limbs, mammals can reduce the surface area and therefore minimize heat loss. This adaptation helps them to conserve heat and stay warm in colder climates.

Reproduction in an overpopulated country like India can be considered both a waste of resources and a burden. With limited resources and a growing population, the strain on resources such as food, water, and energy increases, leading to wastage and depletion. Additionally, overpopulation can also result in overcrowding, unemployment, poverty, and strain on infrastructure and services, further burdening the country's development and progress. Therefore, reproduction in such a scenario can be seen as both wasteful and burdensome.

Xerophytes are plants that have adapted to survive in dry environments with limited water availability. One of the adaptations they have is the presence of sunken stomata. Sunken stomata are located in pits or grooves on the surface of the leaves, which helps to reduce water loss through transpiration. This adaptation allows xerophytes to conserve water and thrive in arid conditions. Hydrophytes, on the other hand, have stomata on the upper surface of their leaves to facilitate gas exchange in water-rich environments. Mesophytes have stomata on the lower surface of their leaves, while halophytes are plants that can tolerate high salt concentrations in their environment.

Stenohaline organisms are those that can only tolerate a narrow range of salinity levels. They are highly sensitive to changes in salinity and cannot survive in environments with extreme variations. This term is commonly used in marine biology to describe species that are adapted to specific salinity conditions, such as freshwater or saltwater habitats. In contrast, euryhaline organisms can tolerate a wide range of salinity levels and are able to adapt to different environments with varying salt concentrations.

Diapause is a stage of suspended development that many zooplankton species enter when they encounter unfavorable conditions. During diapause, the metabolic activity of the organism slows down, allowing it to conserve energy and survive until conditions become more favorable. This state is similar to hibernation or aestivation, but diapause specifically refers to the suspended development of zooplankton.

Halophytes are plants that are adapted to grow in saline or salty soils. These plants have the ability to tolerate high levels of salt in their environment, which allows them to thrive in areas where other plants would struggle to survive. Halophytes have developed various mechanisms to cope with salt, such as specialized root structures and the ability to excrete salt through their leaves. This enables them to extract water from the soil and maintain their physiological functions in saline conditions.

Ecology is the correct answer because it is the scientific study of the interactions between living organisms and their environment. It focuses on understanding how organisms interact with each other and with their physical surroundings. This includes studying topics such as population dynamics, community structure, energy flow, and nutrient cycling. Ecology helps us understand the relationships and interdependencies between organisms and their environment, and how these interactions shape the functioning and sustainability of ecosystems.

If the rate of addition of new members increases with respect to the individuals lost, it suggests that the population is growing at an accelerating rate. This can be represented by exponential growth, where the population size increases rapidly over time. Therefore, the correct answer is exponential growth.

Inbreeding refers to the process of breeding individuals who are closely related to each other within a species. This can lead to a decrease in genetic diversity and an increased likelihood of genetic disorders. Inbreeding can occur naturally when a small population of individuals is isolated, or it can be intentionally done by breeders to maintain specific traits in a population. It is different from euthenics, which refers to the improvement of the environment to enhance the well-being of a species, and eugenics, which involves the selective breeding of individuals to improve the genetic quality of a population.

Malthus stated that human population grows geometrically. This means that the population increases at a constant rate over time. Malthus argued that population growth would eventually outpace the availability of resources, leading to famine, disease, and other forms of population control. He believed that this natural limit on population growth was necessary to prevent overpopulation and ensure the survival of the human species.

Carrying capacity refers to the maximum number of individuals that a particular environment can sustainably support. It is determined by factors such as available resources, space, and other limiting factors. When a population exceeds the carrying capacity of its environment, it leads to competition for resources, overcrowding, and increased environmental degradation. This ultimately hinders the achievement of the highest possible level of population growth, making carrying capacity the correct answer.

An animal's success is determined by its ability to maintain a stable internal environment. This internal environment includes factors such as body temperature and pH levels. By regulating these variables, animals can ensure that their cells and organs function optimally. This ability to maintain homeostasis allows animals to adapt and survive in various environmental conditions, making it a crucial factor in their overall success.

Embryos exhibit exponential growth because they undergo rapid cell division and differentiation during development. This growth is necessary for the formation of complex multicellular organisms from a single fertilized egg. Tissue culture cells, although they can divide rapidly in vitro, do not have the same potential for exponential growth as embryos. Unicellular organisms can also exhibit rapid growth, but their growth is limited by factors such as nutrient availability and space. Multicellular organisms, while they do grow, their growth is typically not exponential as they have reached a certain level of maturity and their growth is regulated by various factors.