Unit 8: Topic 7 - Disruptions to Ecosystems Flashcards
What is an adaptation and where does it come from?
An adaptation starts from a mutation. The mutation may produce an altered phenotype. Depending on the environment, the mutation could make an organism more fit. If it does so, the organism will be better able to survive and reproduce. Therefore, the next generation will have a larger percentage of individuals that have this trait, changing the phenotypic ratios and creating an adaptation.
Do mutations occur in response to environmental pressures?
No, environmental pressures do not cause mutations. Mutations happen at random. They form the genetic variation that exists in a species. Given the environmental pressures of the time (such as increased predation, lack of food or shelter), organisms may be selected through natural selection because of those mutations (which form into adaptations).
What causes mutations and what causes adaptations?
Mutations are caused by a random process. Adaptations are caused by natural selection favoring individuals with certain traits that make them more fit.
What is an invasive species?
An invasive species is one that does not natively belong to that community. It does not naturally have predators, who have adapted to prey on the natural organisms at the time. Invasive species can be brought to different communities by humans. Because of they lack a niche, they are considered to “steal” the resources from other organisms.
What are the effects of introducing an invasive species?
Introducing an invasive species leads to a decrease in resources available for native species due to a lack of predators. The invasive species are better able to compete for food and take over the niche of the native species. This leads to a decrease in population of the native species and decreases genetic diversity.
What does the availability of surplus resources lead to?
The availability of surplus resources leads to uncontrolled population growth and ecological changes.
Over time, what can happen to the distribution of ecosystems?
Overtime the distribution of ecosystems around the world can change. For example, due to global warming, the distribution of Arctic ecosystems is decreasing due to rising global temperatures.
How do humans accelerate change in ecosystems?
Humans can accelerate changes in ecosystems by introducing invasive species which devastate the native species populations. The other way humans accelerate change is through human activity which often causes pollution and serves as a selecting factor.
What effect do geological and meteorological events have on ecosystems?
Geological and meteorological events affect habitat and changes the distribution of ecosystems. These changes can be illustrated by biogeographical studies. For example, earthquakes disrupt the ecosystem by decreasing biomass, decreasing biodiversity and causing soil erosion. The intensity of such earthquakes can be measured using seismometers.
