impacts of human on ecosystems
C3.1 Introduced alien species can escape into local ecosystems and become invasive.
C3.2 Competitive exclusion and the absence of predators can lead to reduction in the numbers of endemic species when alien species become invasive.
C3.3 Pollutants become concentrated in the tissues of organisms at higher trophic levels by biomagnification.
C3.4 Macroplastic and microplastic debris has accumulated in marine environments.
Source: Chapter C and Chapter 4 ecology notes. pdf, and Biology: Oxford IB Diploma Programme book.
C3.2 Competitive exclusion and the absence of predators can lead to reduction in the numbers of endemic species when alien species become invasive.
C3.3 Pollutants become concentrated in the tissues of organisms at higher trophic levels by biomagnification.
C3.4 Macroplastic and microplastic debris has accumulated in marine environments.
Source: Chapter C and Chapter 4 ecology notes. pdf, and Biology: Oxford IB Diploma Programme book.
Alien and invasive species
Introduced alien species can escape into local ecosystems and become invasive.
Human activity often results in an organism being introduced into an area where it did not previously occur.
Species that are native to an area are call endemic species and the ones that are not native are called alien species./
Alien species compete with endemic species
Competitive exclusion and the absence of predators can lead to reduction in the numbers of endemic species when alien species become invasive.The new alien specie can become so reproductively successful and aggressive that it dominates the new ecosystem and poses a serious threat to biodiversity. Organism that are endemic to an area may occupy similar niches as the alien species.
One consequence of the competition might be that either or both species may occupy smaller realized niches. If the alien species lacks predators it may be able to compete with native species and become invasive.
Some ecosystems has the ability to resist to alien species.
Human activity often results in an organism being introduced into an area where it did not previously occur.
Species that are native to an area are call endemic species and the ones that are not native are called alien species./
Alien species compete with endemic species
Competitive exclusion and the absence of predators can lead to reduction in the numbers of endemic species when alien species become invasive.The new alien specie can become so reproductively successful and aggressive that it dominates the new ecosystem and poses a serious threat to biodiversity. Organism that are endemic to an area may occupy similar niches as the alien species.
One consequence of the competition might be that either or both species may occupy smaller realized niches. If the alien species lacks predators it may be able to compete with native species and become invasive.
Some ecosystems has the ability to resist to alien species.
IMPACT OF ALIENS SPECIES
•inter-specific competition/alien species have characteristics that may enable them to out-compete native species
•lack of predators may allow alien species to reproduce more rapidly
•alien species may utilize areas or resources that native species cannot
•predation by invasive species can cause loss of biodiversity
•can lead to species extinction (especially of endangered species)
•alien species may introduce new diseases
•lack of predators may allow alien species to reproduce more rapidly
•alien species may utilize areas or resources that native species cannot
•predation by invasive species can cause loss of biodiversity
•can lead to species extinction (especially of endangered species)
•alien species may introduce new diseases
biomagnification
Pollutants become concentrated in the tissues of organisms at higher trophic levels by bio magnification.
Bio magnification is the process by which chemical substances become more concentrated at each trophic level. At each stage in a food chain, the predator will accumulate higher concentrations of the toxin than its prey.This is because the predator consumes large quantities of prey during its lifetime and bio accumulates the toxins that they contain.
The concentration of toxins in the highest trophic levels may be lethal, even when the concentrations in organisms at the start of the food chain were very low.
Bio magnification is the process by which chemical substances become more concentrated at each trophic level. At each stage in a food chain, the predator will accumulate higher concentrations of the toxin than its prey.This is because the predator consumes large quantities of prey during its lifetime and bio accumulates the toxins that they contain.
The concentration of toxins in the highest trophic levels may be lethal, even when the concentrations in organisms at the start of the food chain were very low.
plastics in the ocean
Plastic is a broad term that describes a number of different polymers that are used in a growing number of disposable consumer items. Some plastic enters the ocean through direct disposal from ships and platforms, however the majority comes form litter being blown into the water.
Macro plastic is large visible debris including nets, buoys, buckets and trash that has not degraded.
Physical and chemical degradation of macro plastic results in micro plastic fragments that are harder to see but are more omnipresent
Consequences of marine plastic pollution
-The degradation of plastic at sea releases persistent organic chemicals into the occean
-Plastic absorb other persistent organic chemicals and thus concentrate these toxins
-Animals eat or become tangled in plastic pollution.
Macro plastic is large visible debris including nets, buoys, buckets and trash that has not degraded.
Physical and chemical degradation of macro plastic results in micro plastic fragments that are harder to see but are more omnipresent
Consequences of marine plastic pollution
-The degradation of plastic at sea releases persistent organic chemicals into the occean
-Plastic absorb other persistent organic chemicals and thus concentrate these toxins
-Animals eat or become tangled in plastic pollution.
INTERNATIONAL MINDEDNESS
Over 100 countries across the globe have agreed to ban the production of CFCs to reduce the depletion of the ozone layer.
UNDERSTANDING:
- Introduced alien species can escape into local ecosystems and become invasive
- Competitive exclusion and the absence of predators can lead to reduction in the numbers of endemic species when alien species become invasive
- Pollutants become concentrated in the tissues of organisms at higher trophic levels by biomagnification
- Macroplastic and microplastic debris has accumulated in marine environments
APPLICATIONS:
-Study of the introduction of cane toads in Australia and one other local example of the introduction of an alien species
- Discussion of the trade-off between control of the malarial parasite and DDT pollution
- Case study of the impact of marine plastic debris on Laysan albatrosses and one other named species
SKILLS
- Analysis of data illustrating the causes and consequences of biomagnification
- Evaluation of eradication programs and biological control as measures to reduce the impact of alien species
Notes: The understanding, application and skills help us understand the content of this unit. They give us good examples and key points to study for the exams.