3.2 Study Guide Flashcards
What is the definition of Ecological Succession?
The transition in species composition over time.
What is the definition of Primary Succession?
The process of a barren, almost lifeless, area developing into a diverse community with high biodiversity.
What is the definition of Secondary Succession?
The restoration process that a previously climax community goes through to redevelop after a disturbance to the environment.
What is a pioneer species?
The first colonizers of a new area. These species can include lichens, mosses, ferns, and bacteria– all organisms with low nutrient requirements.
What are the seral stages?
The seral stages are where new colonizers begin to take over and the habitat starts to become more diverse. The new plants are larger and cast shadows over the pioneer plants. Animals will also appear and feed on the more diverse food source. The pioneer plants will die and decompose and the animals will leave behind manure. these both add to the thin layer of soil.
What is a climax community?
A climax community is one that is stable and has biodiversity. The community has matured and is sustainable. The plants are slow-growing, the soil quality has improved, and there are a variety of species living there.
What is species richness?
Represented by the symbol (R), species richness is the number of species found in a given area.
What is species evenness?
A measure of how similar the abundance of different species are. When there are similar proportions of all species then evenness is one, but when the abundance is very dissimilar then the value increases.
What is genetic diversity?
Genetic diversity is a variation in the gene composition of organisms in the same species. Genetic diversity allows for more variety and allows a species to adapt to changes in their environment and survive.
What is ecological diversity
The range of habitat types. Variation within ecosystems. More niches=more species
What is a keystone species?
An organism that helps define an entire ecosystem. Keystone species have low functional redundancies.
What is an invasive species?
A non-native species that causes harm to the environment. The species inhibits the development of the ecosystem.
What is the difference between primary and secondary succession?
In a primary succession, the area has to grow from a completely barren rock land, to a climax community with biodiversity. However, in a secondary succession, the base soil is still present, so the plants can regrow much faster. Secondary succession is a revival from a disruption, while primary succession is a completely new development of a community.
How do keystone species and invasive species affect biodiversity?
Keystone species affect biodiversity because they dominate the community. The large presence of these species does not allow for there to be a variety of species living in the area, which leads to a lower biodiversity. Invasive species also have a negative effect on biodiversity. Invasive species inhibit the colonizing species by taking their resources. Without resources, the colonizing species will not be able to grow and develop. This affects biodiversity because many of the species will not be able to survive due to a lack of resources.
Calculate the Shannon-Wiener Index for this community using the equation H=-E(Sigma) (Pi ln[Pi]). There are 5 species and each has a population size of 40.
H=1.61
How do species richness values affect biodiversity?
A higher species richness results in higher biodiversity because there is a greater variety of the species living in the area. More species=more variety. A lower species richness value results in lower biodiversity because there are fewer species.
How do species evenness values affect biodiversity?
The closer the evenness value is to one, the more evenly distributed the species in the community are. A low evenness value means that there is high biodiversity because the number of each species is similar. A higher evenness value would mean that there is more dominance, resulting in less biodiversity.
How do the Shannon-Wiener Index (H) values affect the biodiversity of a community?
A high H value means that it is more difficult to predict which species will be seen next. If an individual is picked at random and you take a guess at what species it is, there is a very low chance that you are correct. A low H value means that the community lacks biodiversity because it is easy to predict which species you will find if you pick an individual at random. If there is only one species in the area, then of course you will get the prediction right every time.
Examples of primary and secondary succession:
Primary: Melting, receding glaciers that are taking the soil away. The community will have to completely regrow from the barren rock land.
Secondary: Major flooding of a creek bed. The base soil would still be present, so the community would be able to grow back more quickly than a primary succession.
