How does a distribution curve of body lengths for a population of fish change after a predator preys on both extremes of body length (short and long)?
It becomes narrower and taller
The distribution curve of body lengths for a population of fish would shift towards the middle, as the predator would have removed the individuals with the shortest and longest body lengths. This would result in a narrower range of body lengths in the population.
When a predator preys on both extremes of body length in a population of fish, it can lead to changes in the distribution curve of body lengths. Here are the step-by-step changes that may occur:
1. Initial Distribution Curve: Before the predator preys on the fish, the population may have a distribution curve of body lengths that is relatively normal or bell-shaped. This means that the majority of fish fall within the middle range of body lengths, with fewer fish at the extremes.
2. Predator Preying on Short and Long Body Lengths: The predator targets fish at both ends of the body length spectrum. It preys on the shorter fish as well as the longer fish. This implies that the predator is selectively removing individuals that deviate from the average body length.
3. Decrease in Extreme Body Lengths: As the predator preys on the shorter and longer fish, the number of individuals at the extremes of body length will start to decrease. This can lead to a flattening of the distribution curve as the proportions of shorter and longer fish decrease.
4. Increase in Intermediate Body Lengths: With the removal of shorter and longer individuals, the distribution curve is likely to shift towards the middle range of body lengths. The proportion of fish with intermediate body lengths will increase, as these individuals are less likely to be preyed upon.
5. Potential Shift in Mean and Standard Deviation: The predator's impact can also cause a shift in the mean (average body length) of the population. If the predator selectively removes longer fish, the mean body length may decrease. Additionally, the standard deviation (a measure of the spread of body lengths) may decrease as the range of body lengths narrows.
6. New Distribution Curve: After the predator has preyed on both extremes of body length, the distribution curve may become more concentrated around the average body length, potentially appearing narrower and less skewed compared to the initial curve.
It is important to note that the exact changes in the distribution curve will depend on various factors such as the intensity of predation, reproductive patterns, and the presence of other factors influencing body length distribution.
To understand how a distribution curve of body lengths for a population of fish changes after a predator preys on both extremes of body length, we need to consider the concept of natural selection and its effects on the population.
Here's how you can understand the change in the distribution curve:
1. Initial Distribution: Start with a population of fish where the body lengths are normally distributed, forming a bell-shaped curve. This means that most fish have an average body length, with fewer fish having shorter or longer lengths.
2. Predator Prey Effect: When a predator preys on both extremes of body length, it means that the shorter and longer fish have a higher chance of being eaten compared to the fish with average body lengths.
3. Natural Selection: As the predator continues to prey on the extremes, there will be selective pressure on the population. Fish with body lengths closer to the average have a higher survival rate since they are less likely to be targeted by the predator.
4. Changes in Population: Over time, the fish with shorter and longer body lengths experience a higher mortality rate due to predation. In contrast, fish with average body lengths survive and reproduce more successfully.
5. New Distribution: As a result of the predator selectively removing fish at the extremes, the distribution curve will undergo changes. The curve will become narrower and peak towards the average body length, as the individuals with extreme lengths decrease in number.
6. Evolutionary Effects: With natural selection favoring fish with average body lengths, subsequent generations will increasingly consist of fish with lengths closer to the average. This can lead to the evolution of the population, as the proportion of fish with extreme body lengths reduces in subsequent generations.
In summary, the distribution curve of body lengths for a population of fish will become narrower and peak towards the average body length after a predator preys on both extremes. This is a result of natural selection favoring individuals with average lengths, leading to changes in the population's genetic makeup over time.