Biodiversity
What is species diversity?
This type of biodiversity refers to the variety of life at the level of species within an ecosystem.
What is r-selection?
This method of reproduction involves organisms producing many offspring with little parental care, often seen in species with high reproductive rates.
What is photosynthesis?
Solar energy is captured by plants during this process, where light energy is converted into chemical energy stored in glucose.
This term describes the maximum population size that an environment can support indefinitely.
Carrying capacity
This term refers to the process of change in the structure and composition of a community over time, starting from pioneer species to a stable ecosystem.
Ecological succession.
What is species evenness?
Species richness refers to the number of different species in a given area. This term, which describes the relative abundance of species in that same area, helps provide a more complete measure of biodiversity.
What is the Linnaean system, and how does it involve binomial nomenclature?
This classification system groups organisms based on physical similarities and organizes them hierarchically from Kingdom, phylum, class, order, family, genus and species. The binomial nomenclature gives each species a two part name of the Genus followed by the species.
This principle states that two species competing for the exact same resources cannot coexist in the same niche.
competitive exclusion principle
Carrying capacity is influenced by limiting factors. Name one biotic and one abiotic factor that can limit population growth.
biotic factor is food availability, and an abiotic factor could be water availability.
There are two main types of ecological succession. One occurs in areas with no previous soil, like after a volcanic eruption, and the other occurs after a disturbance in an existing ecosystem. What are these two types?
primary succession and secondary succession
What is the Simpson’s Diversity Index?
This index is commonly used to measure biodiversity by accounting for both species richness and evenness within an ecosystem.
What is cladistics (or molecular phylogeny)?
A clade refers to a group of organisms that includes a common ancestor and all of its descendants. This classification is commonly used in this system of evolutionary relationships.
Microorganisms occupy unique ecological niches due to their ability to decompose organic material and recycle nutrients in ecosystems. What is the role of decomposers in the carbon and nitrogen cycles?
Decomposers break down dead organic matter, releasing carbon as carbon dioxide and converting nitrogen in organic material into ammonia, which can then be further processed into nitrates by nitrifying bacteria.
A population's growth rate is influenced by births, deaths, immigration, and emigration. How would you calculate the population growth rate using these factors?
Population growth rate = (births + immigration) - (deaths + emigration).
Pioneer species play a critical role in initiating succession. Name two characteristics that make pioneer species effective colonizers of harsh environments.
nitrogen fixation and tolerance to extreme conditions (or rapid seed germination and ability to photosynthesize
Environmental factors such as climate, substrate, and the size or depth of an area can limit these key features of an ecosystem that reflects the number of individuals and range of species.
distribution and abundance of species
What is the assumption of common ancestry (or bifurcation or physical change)?
When analyzing a cladogram, organisms that are located closer together on the diagram are inferred to share a more recent common ancestor.
In an ecosystem, the transfer and transformation of carbon occur as it moves between the atmosphere, organisms, and soil. How is carbon transformed as it cycles through photosynthesis, respiration, and decomposition?
During photosynthesis, carbon dioxide is fixed into organic compounds like glucose; through respiration, these compounds are broken down, releasing carbon dioxide back into the atmosphere. In decomposition, dead organic matter is broken down by decomposers, also releasing carbon dioxide.
The Lincoln Index is used to estimate population size. If 100 individuals are captured, marked, and released, then 120 individuals are captured later with 30 marked, what is the estimated population size?
M, Marked = 100
n, new capture = 120
m, captured and marked = 30
(100 x 120) / 30 = 400Fossil records provide evidence of past ecosystems. If you find fossil evidence of a species that was replaced by another over time, what does this suggest about the succession process in that ecosystem?
The fossil evidence suggests that ecological succession occurred, with one species (likely a pioneer species) being replaced by others as the environment became more stable, moving towards a climax community.
What are two techniques that can be used within this method to accurately assess the species diversity of an area, and how do they minimize bias?
Quadrats and transects.
Minimizing bias can be achieved through random sampling, using random-number generators, and ensuring the appropriate size and number of samples.
Stratified sampling is used to determine population density and distribution across environmental gradients. How does stratified sampling help in classifying ecosystems, and why is this classification important for effective ecosystem management?
Stratified sampling divides the habitat into sections (strata) for more accurate representation of species diversity. This process is essential for classifying ecosystems because it provides detailed data on species distribution, aiding in effective management practices, such as for old-growth forests or coral reefs.
Analyse the image from an Australian ecosystem showing changes in population sizes after the removal of a keystone species. Predict the long-term effects on the biodiversity of this ecosystem and explain why keystone species are crucial for ecosystem stability.
Without the keystone species, the ecosystem may experience a decline in biodiversity due to unchecked population growth of certain species (such as herbivores), leading to overexploitation of resources and habitat degradation. Keystone species maintain trophic balance and prevent dominant species from monopolizing resources, allowing for greater diversity.
A population initially exhibits rapid growth, followed by a plateau as it reaches the environment’s carrying capacity. Which population growth model is this, and how do changes in limiting factors like food availability or disease affect the carrying capacity of the ecosystem?
S-curve. Changes in limiting factors like a decrease in food availability or an increase in disease can lower the carrying capacity, as fewer resources or higher mortality rates reduce the number of individuals the environment
Human activity such as deforestation and urbanization can reduce biodiversity and alter ecosystem dynamics. Predict how such activities might affect the speed and magnitude of ecological succession in a disturbed area.
Human activity often accelerates the initial disturbance (e.g., clear-cutting forests), which can lead to faster secondary succession due to increased availability of space and resources. However, the reduction of biodiversity and introduction of invasive species can limit the ecosystem's ability to recover fully, potentially reducing the magnitude and duration of succession toward a stable climax community.