Question

The general traits of species prone to extinction, as well as those that might be prone to become invasive species, represent an important set of contrasts.

1. Compare and contrast the traits of species that are more prone to extinction and those that might be more prone to becoming invasive.

2. Given the trajectory our planet is currently in (i.e., rising rates of extinction and increasing occurrences of invasive species), what do you think the world might look like in terms of its biota in the next 1 to 2 centuries? (Hint: You should think about the Monster of God Reading that posed this exact question concerning invasive species and differential extinction patterns).

You should be able to complete this in 4-5 paragraphs.

Answer 1

1. Species at the verge of extinction may have faced destruction in habitat or some form of climatic change, predation or human activities which leads to more killing than the birth of new organism, thereby reducing gene pool and hence survival rate.

The similar conditions prevail for invasive species which are forced to live in an environment to which it does not belong naturally. But instead of getting extinct, they start damaging the local environment.

The simple reason for this could be lack of any natural predators or pests to restrict their population growth. However, an organism invasive for one ecosystem could not be invasive for other ecosystems.

1. In the current scenario, the rate of invasion by foreign species in a local ecosystem has increased tremendously. This is because of the potential changes in land form and climatic conditions.

The current global trading pattern allows easy transfer of species from one ecosystem to the other. The greater is the number of species crossing borders, the greater is the buildup of invasive potential of non- native species. With frequent trading, the immigrant population of non- native species increases.

It has been observed in several cases that a non- native species whose population remained at a lower number suddenly surged after few years thereby causing lag effect due to normal increase in size and distribution of a population.

Along with demographical factors, there are several other factors that have cause subsequent spread of non- native species –

a) Environmental change - biotic and abiotic factors

b) Genetic changes to the founder populations

The accumulative adverse effects due to large numbers of species involved increases with the increased rate of exchange thereby creating amassed lag debts. In near future such cumulative premises could lead to creation of man eating predators as mentioned in the Monster of God