Question

Identify two factors that could possibly cause a population to decline to extinction. How might population size influence the impact of these factors?

Short answer

Answer: The two factors that could lead to a population decline to extinction are environmental catastrophes and over-exploitation. Population size plays a significant role in determining the impact of these factors. Large populations have a higher chance of recovering from environmental catastrophes and withstanding over-exploitation since they have more individuals that can reproduce and maintain genetic diversity. On the other hand, smaller populations are more vulnerable to the impacts of these factors, and as the population size decreases, the risk of extinction increases.

Step-by-step solution

Identify two factors that could cause a population to decline to extinction

Two factors that could possibly cause a population to decline to extinction are: 1. Environmental catastrophes: Natural disasters such as floods, volcanic eruptions, and hurricanes can destroy habitats and cause the death of a large number of individuals in a population. 2. Over-exploitation: Human activities, such as over-hunting, over-fishing, or habitat destruction, can lead to a significant reduction in the number of individuals in a population, making it more vulnerable to extinction.

Population size and the impact of environmental catastrophes

The impact of environmental catastrophes on a population and its potential extinction largely depends on the size of the population. When a population is large, it has a higher chance of recovering from the loss of individuals caused by an environmental catastrophe. This is because, with more individuals available to reproduce, the population can recover more quickly, and genetic diversity will be less affected. On the other hand, if the population is small, the loss of individuals due to an environmental catastrophe can be devastating. With fewer individuals available to reproduce, the population might not recover, genetic diversity will be more affected, increasing the risk of extinction.

Population size and the impact of over-exploitation

The impact of over-exploitation on a population's risk of extinction also depends on its size. Larger populations can better withstand the pressure of over-exploitation since they have more individuals that can reproduce and replace the lost individuals. However, as the population size decreases due to over-exploitation, the risk of extinction increases. Smaller populations have fewer individuals that can reproduce and are more vulnerable to the impacts of over-exploitation. Moreover, as the population becomes smaller, genetic diversity may be lost, further increasing the likelihood of extinction. By understanding the relationship between population size and the impact of factors like environmental catastrophes and over-exploitation, we can better predict and prevent extinction events in vulnerable species and conserve biodiversity.

Key concepts

Environmental Catastrophes

Environmental catastrophes are sudden natural events that can significantly impact life on Earth. These include disasters such as earthquakes, floods, hurricanes, and volcanic eruptions. When such events occur, they pose a direct threat to populations. They can destroy habitats, causing immediate loss of shelter and resources for many species.

The aftermath can be severe, leading to the death of numerous individuals within a population. For instance, a hurricane can result in massive habitat destruction, leaving affected species with nowhere to go.

• These events not only decrease population numbers quickly but can also disrupt the ecosystem balance.
• Animals and plants used to living in certain conditions can find themselves suddenly vulnerable.

When population numbers are diminished, the ability of the population to recover depends greatly on the initial size of the population involved.

Over-exploitation

Over-exploitation refers to the unsustainable use of natural resources by humans. This includes activities like over-fishing, over-hunting, and deforestation. Such practices can lead to rapid declines in species numbers, pushing them towards extinction.

When humans harvest more individuals than a population can replace through reproduction, it leads to a shrinking population size. For example, over-fishing in oceans can lead to fish populations not having enough time to reproduce. This reduces their numbers drastically.

• Such pressure on populations often reduces reproductive success, making it harder for species to bounce back.
• Over-exploitation often results in habitat loss, which further challenges species survival.

Sustainable management of resources is crucial to prevent such outcomes.

Population Size

Population size plays a pivotal role in a species' survival and adaptability. A larger population generally has greater resilience against negative factors such as environmental changes or human impacts.

Large populations benefit from a larger gene pool, which can offer protection against diseases and increase adaptability to changing environments.

• They have a higher probability of recovery after disturbances due to more individuals reproducing.
• The genetic diversity within a large population reduces the chance of inbreeding and maintains a healthy, dynamic population.

However, when populations are small, they are much more vulnerable to extinction threats.

Genetic Diversity

Genetic diversity refers to the variety of genes within a population. Higher genetic diversity means a wider range of traits, which enhances a population's ability to adapt to environmental changes.
Low genetic diversity can make populations more susceptible to diseases and unable to cope with habitat changes. It limits the potential for adaptation due to reduced variability in traits possible within a species.

• A genetically diverse population is better equipped to deal with unforeseen challenges.
• Diversity helps ensure some individuals can survive adverse changes and pass on their traits.

In small populations, genetic diversity tends to decrease due to inbreeding and genetic drift, increasing extinction risk.