Populations & Ecosystems Test - 6

Characteristics of a Population vs. Individual Organism

• Births and deaths: These are characteristics of a population as they reflect the overall population dynamics rather than individual organisms.



• Birth rates and death rates: Population-level data on birth and death rates provide insights into the growth or decline of a population, which is not applicable to individual organisms.



• Sex ratio: While sex ratio can vary among individuals, it is more commonly used to describe the distribution of males and females in a population as a whole.



• Age distribution: Age distribution, such as the proportion of individuals in different age groups, is a population-level characteristic that helps understand the structure of a population.

In summary, characteristics such as birth rates, death rates, sex ratio, and age distribution are more relevant to populations as a whole rather than individual organisms. These factors provide valuable insights into the dynamics and structure of a population, highlighting the importance of studying populations as distinct entities from individual organisms.

In the given scenario, the laboratory population of fruit flies consists of 40 fruit flies, and during a specified time interval, 4 individuals died. To calculate the death rate, we divide the number of deaths by the total population.

Number of deaths = 4
Total population = 40

Death rate = Number of deaths / Total population
= 4 / 40
= 0.1 individuals per fruitfly per week

Option a) "0.1 individuals per fruitfly per week "is the correct answer because it accurately represents the death rate calculated based on the given information.

Natural selection operates on the population level to evolve desired traits. While individual organisms have to cope with changes in their environment, it is at the population level that natural selection acts to shape the genetic composition and traits of the population over time.

Population ecology, links ecology to population genetics and evolution. It is at the population level that variations in traits occur due to genetic diversity and interactions with the environment. Individuals with traits that confer advantages in survival, reproduction, and adaptation are more likely to pass on those traits to the next generation through interbreeding.

An age pyramid with a wide base and narrow top indicates a population that is growing rapidly.

In an age pyramid, the width of each age group represents the proportion or percentage of individuals in that specific age group. A wide base indicates a larger population of young individuals, while a narrow top indicates a smaller population of older individuals.

When the base of an age pyramid is wide and the subsequent age groups gradually decrease in width towards the top, it suggests that there is a higher proportion of young individuals compared to older individuals. This is indicative of a population that is growing rapidly because there is a high birth rate.

• Our intestine is a unique habitat for hundreds of species of microbes. Digestion is important for breaking down food into nutrients, which the body uses for energy, growth, and cell repair.
• Food and drink must be changed into smaller molecules of nutrients before the blood absorbs them and carries them to cells throughout the body.
• The intestines are a long, continuous tube running from the stomach to the anus. Most absorption of nutrients and water happen in the intestines.
• The intestines include the small intestine, large intestine, and rectum.

A population 's birth rate refers to the number of births per capita. A population has birth rates and death rates, and these rates are expressed as changes in numbers (increase or decrease) with respect to members of the population.

To calculate the birth rate, the number of births is divided by the population size or the number of individuals in the population. The birth rate per capita provides a measure of the average number of births per individual in the population .

Carrying capacity of a habitat is the maximum number of individual that can survive in given habit. There is a limitation of food, water and space in a habitat so only limited numbers of individual survive.

Interactions between different species living within a particular area may be useful as in case of mutualism, fatal as in case of parasitism or neutralin which no one is harmed.

Interacting members of species live close to each other in commensalism, predation and parasitism.

A majority of organisms are restricted to narrow range of temperature. Such organisms are called stenothermal species. The distribution range of these species will be adversely affected if average global temperature keeps increasing.