In the 1800s, a disease ruined much of the potato crop in Ireland. Since many Irish people depended on potatoes as their main food source, mass hunger and migration resulted. The potato blight caused Ireland's population to drop.
For a population to be healthy, resources such as food, nutrients, water, and space, must be available. Limiting factors are any resources that can lower the population size by decreasing birth rates, increasing death rates, or leading to migration. Some examples of limiting factors include a low food supply and a lack of space.
Biotic limiting factors are living things in an environment, including available food and the number of predators. Limiting factors that are not living things are called abiotic factors. Some examples include available sunlight, water, nutrients, oxygen, and temperature of the habitat.
A struggle for resources like food and space causes a population to stop growing. When a population’s growth rate is decreasing, it is because the population has reached its carrying capacity. The carrying capacity is the largest population that can be supported in an area without destroying the habitat. Limiting factors decide the carrying capacity of a population. If there are 12 hamburgers at a lunch table and 24 people sit down at a lunch table, will everyone be able to eat? At first, you may just split hamburgers in half. However, if more and more people keep coming to sit at the lunch table, you will not be able to feed everyone. In nature, any organisms (living things) that cannot get food will either move to find a new place to live or they will die.
In nature, when the population size is small, there is usually plenty of food for everyone. Organisms can easily breed, so the birth rate is high. As the population increases, the amount of resources may drop.
When necessary resources like food and space disappear, some organisms will die. Then the birth rates drop, and population growth rate decreases. This natural cycle repeatedly happens until the population reaches equilibrium, where the number of organisms and the resources available is balanced.
1. How does a decrease in abiotic resources impact the population growth in an ecosystem?
A. The population size will increase
B. The population size will decrease****
C. The population size will not change
2. What determines the carrying capacity in an ecosystem?
A. The number of different species in the ecosystem
B. Limiting factors
C. Only biotic factors****
D. Only abiotic factors
3. Which of the following is an example of two organisms competing for an abiotic factor?
A. Two different species of insects competing for leaves from trees
B. Two different species of mammals competing for small rodents to eat****
C. Two different species of birds competing for berries to eat
D. Two different species of mammals competing for the same water source
I answered this below. Only your first answer is correct.
shortage of biotic (like potatoes) or abiotic (like sunlight) Both LIMIT capacity
water for example is abiotic (not biological). Rodents are biotic.
1. The population size will decrease.
2. Limiting factors determine the carrying capacity in an ecosystem.
3. Two different species of mammals competing for the same water source is an example of two organisms competing for an abiotic factor.
1. The correct answer is B. The population size will decrease. A decrease in abiotic resources such as food, water, or space can lead to a decrease in population growth. When necessary resources disappear, organisms may not be able to survive or reproduce, causing the population size to decrease.
2. The correct answer is B. Limiting factors determine the carrying capacity in an ecosystem. Limiting factors, both biotic and abiotic, determine the maximum population size that can be sustained in an area without depleting the resources or destroying the habitat. These factors include the availability of food, water, space, sunlight, temperature, and other essential resources.
3. The correct answer is D. Two different species of mammals competing for the same water source. This is an example of two organisms competing for an abiotic factor, in this case, water. Different species of mammals competing for the same water source may have to compete for access to this limited resource, which can affect their survival and reproductive success.