Populations and Sustainability Flashcards
What are the phases of a population growth curve?
Phase 1 - a period of slow growth. The small numbers of individuals that are initially present reproduce which increases the total population.
Phase 2 - a period of rapid growth. As the number of breeding individuals increases, the total population multiplies exponentially.
Phase 3 - a stable state (despite fluctuations). Birth rates and death rates are approximately equal.
What are abiotic factors?
Non-living factors including temperature, light, pH, humidity, availability of water or oxygen.
What are biotic factors?
Living factors like predators, competition and disease.
What are limiting factors?
They prevent further growth of a population and in some cases, cause it to decline.
What is carrying capacity?
The maximum population size that an environment can support.
What is immigration?
The movement of individual organisms into a particular area, which increases population size.
E.g., millions of Christmas Island red crabs migrate each year from forest to coast to reproduce.
What is emigration?
The movement of individual organisms away from a particular area which decreases population size.
E.g., the Norway Lemming emigrates away from areas of high population density or poor habitat.
What are density dependant factors?
They have an effect on the whole population regardless of its size. These can dramatically change the population size.
These factors include earthquakes, fires, volcanic eruptions and storms.
What is interspecific competition?
Competition between different species.
What is infraspecific competition?
Competition between members of the same species.
What is conservation?
The maintenance of biodiversity through human action or management. This includes maintaining diversity between species, maintaining genetic diversity within a species, and the maintenance of habitats.
What is preservation?
The protection of an area by restricting or banning human interference, so that the ecosystem is kept in its original state.
Economic importance of conservation.
To provide resources that humans need to survive and to provide an income.
E.g., rainforest species provide medicinal drugs, clothes and food that can be traded.
Social importantce of conservation.
Many people enjoy the natural beauty of wild ecosystems as well as using them for activities which are beneficial to health by providing a means of relaxation and exercise.
E.g., walking, bird watching, cycling and climbing.
Ethical importance of conservation.
All organisms have a right to exist, and most play an important role within their ecosystem. Many people believe that we should not have the right to decide which organisms can survive, and which we can’t live without. We also have a moral responsibility for future generations to conserve the wide variety of existing natural ecosystems.
