Predicting Consequences for populations in ecosystems Flashcards
What is the main impact of predation on an ecosystem.
Prey and predator populations with fluctuate over time.
Describe how predator numbers mirror those of prey.
When lots of prey is available, predator population increases. As prey are consumed, their numbers decline, leading to a shortage of food for predators, whose numbers then decline as well.
What factors affect predator and prey populations?
Number of predators competing, availability of food for prey, reproduction rates, death rates, size of ecosystem, number of shelters.
What does competition in an ecosystem affect?
Competition affects reproduction and survival rates.
Describe how competition may influence the populations of competing species.
If species are competing for a common resource, if the resource becomes more abundant, both species will also become more abundant, and vice versa. Or, one species may out-compete the other
Describe what occurs when one species is more competitive.
The less competitive species is driven to low numbers and will eventually become extinct, unless other factors intervene,
What factors may allow a less competitive species to survive?
environmental factors such as temp, or the availability of the shared resource., or the species adapts or moves to a different niche.
Provide an example of species competition causing extinction.
Two species of paramecium grown in the same test tube competed, and one competed successfully for nutrients and killed the other species. (1934 experiment)
What are the main impacts of symbiosis?
Increased biodiversity
Development of new species via symbiogenesis
Sources of new capabilities for organisms.
How does symbiosis increase biodiversity?
Eg. coral and algae in symbiosis create coral reefs, habitat for diverse range of organisms.
How does symbiogenesis form new species.
Symbiogenesis is the formation of new species through the genetic incorporation of two species. Eg. prokaryote became eukaryotic when engulfed mitochondria and had symbiotic relationship.
Describe how symbiosis generates sources of new capabilities for organisms.
Symbiotic relationships can provide new opportunities for organisms. Eg. legumes in symbiosis with nitrogen fixing bacteria. The bacteria exploit the relationship, became parasite and take sugar without providing nitrogen.
What is a disease?
A process that adversely effects the normal functioning of an organism.
What allows a disease outbreak to occur?
A pathogen must be introduced to a new host population from where it can spread.
How does human activity contribute to disease outbreaks?
Climate change, deforestation and environment degradation can increase breeding sites for vectors, allow the invasion of pathogens. Use of antibiotics and pesticide creates resistant organisms. Loss of habitats create overcrowding - spread faster.
