environmental sciences

Question

In an area with an ecological gradient,the relative abundance of plants and animals changes to according to  a) human population b) elevation c) biome type d) number of species

Answer 1

Background: An ecological gradient is described by changes in both abiotic (non-living) and biotic (living) factors in an area. So this area could be characterized by an abiotic change (water depth, altitude, soil pH, temperature, etc.), which in effect will result in a change in the biotic/ living factors (the numbers and types of species present as you move along that gradient).

This question is trying to test if you understand the CAUSE of the ecological gradient. The ultimate cause is going to be the abiotic factors, often called the environmental gradient. For example, if average temperature (abiotic CAUSE) drops along a gradient, you will get different types of (Biotic EFFECTS) trees/ vegetation, different animals that can feed on it, and different sizes of populations (warmer populations can typically produce more and thus have higher biodiversity).

So defining each answer in context of the question:

A) Human Population-- EFFECT-- it's likely less people would live at higher elevations. *

B)ELEVATION- CAUSE- also note that this is abiotic

C)Biome Type- EFFECT- The biome type will change with increasing elevation as a result of decreasing temperature

D) Number of Species- EFFECT- The number of species will change as a result of the elevation.

*it's worth noting that the human element can always through a wrench into our classical understanding of things and you might be thinking that human population (choice A) and human disturbance is likely the cause, but then the answer choice should state a specific human disturbance that causes an abiotic change. This does not.