The study of how organisms interact with each other and their environments

The overall health of a population can often be monitored by tracking this

This curve shows that individuals are more likely to die when they are old

These are parts of an ecosystem that are living or used to be living

This was the last year the golden toads were seen

At this level, the science of ecology involves describing relationships between individual organisms and their physical environments

When population size declines quickly, it means this is coming

These types of animals tend to have a type II survivorship curve, having no high time to die

Plants using light to perform photosynthesis is an example of this

The name Bufo periglenese means this

All of the golden toads that live together in the Monteverde region are members of this

This downside of high population density makes organisms more vulnerable to predators that feed on them

Population size, density, distribution, sex ratio and age structure all influence this ratio to determine population growth

Competition is a density-this type of factor because the higher the population density, the less food and water will be available

In the spring of 1987, these conditions caused the breeding pools to dry up almost completely

The scientific name Homo sapiens and Bufo periglenes describe this

There are three ways populations can be distributed, random, clumped and this

This type of growth occurs when a population increases by a fixed percentage each year. It is also does not last long or occur often in nature

The result of these factors are always the same, a dramatic and sudden reduction in population size

The hot, dry conditions were to blame for high adult this, which caused breeding problems

Unlike communities, these include not only living things but nonliving as well

In 1914, the last of these on Earth died

In logistic growth, population size stabilizes around this

Forest soil, rocks, leaf litter, humidity and plant life all make up this

In a 1999 paper, three scientists reported that higher clouds and decreasing this in the forest could explain the disappearance of the golden toads