Question

For the graph depicting the Theory of Island Biogeography Distance to Mainland Bland Area Latinction Rate (Immigration or Extinction) Number of Species Present

Answer 1

Okay, this model waas proposed by McArthur and Wilson since 1963. It states that smaller islands have greater possibilities of getting species extinct, the greater the island the less probabilities will bw for its species to go extinct; on the other hand there is another factor: distance to mainland. It states that islands closer to mainland have greater possiibilities of recieving migrants, so the closer the island to mainland the more migrants it will recieve, So large island have low extinction probabilities, small islands have large extinction probabilities, close islands have larger probabilities of recieving migrants, while more distant islands have lower probabilities of recieving migrants

These two factors have an impact on species richness, as extinction reduces such richness and migration increases it.

- Would extinction on these islands be considered density dependent? Yes

Density is a major factor related to extinction is small islands, density is the relation between space and population size, small islands have limited space and any change in population size affects density. Small population sizes may lead to extinction, then low densities in small islands tend to indicate getting closer to extinction

- Ara insects more likely to go extinct on an island compared to birds? Yes

That is because birds have greater migration probabilities than insects in the same conditions (distance to mainland). Birds have higher flying abilities, so migration tends to be easely done, while insects don't have such support to evade extinction

- Is habitat diversity likely to play a role regarding which species survive? Yes

Available habitats is a crucial factor for species survival, even if an island is large enough to consider extinction has not big probabilities if the entire island doesn't have the required habitat then the species in question will not survive

- Does the size of the island determine how many species can be present? Yes

Island's size is related to species richness but only in an indirect way. Larger islands do have more space for each individual to acommodate, but habitat richness is another matter. Larger islands tend to have greater habitat richness too but it is not a must. So, in some cases, even if the island is large there might be few different habitats, leading a not so large number of species.

- Are large islands more susceptible to random environmental events? Yes

Larger space gives opportunity to climate differences, habitat richness, thus leading to more frequent and diverse environmental events.

What is the term for a genetic individual? In this terms it would be Effective Migrant