BIODIVERSITY
What are the three levels of biodiversity?
Genetic diversity, species diversity and ecosystem diversity.
A population has:
What is the population change?
Population change = births + immigration − deaths − emigration
= 40 + 10 − 15 − 20
= +15 individuals
What is the difference between a biotic factor and an abiotic factor?
A biotic factor is a living component of an ecosystem, while an abiotic factor is a non-living environmental factor.
A lion kills and eats a zebra.
What type of species interaction is this?
Predation
What is ecological succession?
The gradual change in the species composition and structure of an ecosystem over time.
A forest contains 25 different species. What measure of biodiversity is being described?
Species richness.
A population begins with 200 individuals. During the year there are 35 births, 20 deaths, 15 immigrants and 10 emigrants.
What is the final population?
200 + 35 − 20 + 15 − 10 = 220 individuals
Name three abiotic factors that could influence where a species is found.
Possible answers include:
Two bird species require the same limited nesting sites.
What type of interaction is occurring?
Competition.
What is the key difference between primary and secondary succession?
Primary succession begins where there is no existing soil, whereas secondary succession occurs where soil remains after a disturbance.
What is one major limitation of the biological species concept?
It cannot be easily applied to organisms that reproduce asexually, fossils or populations where reproductive compatibility cannot be tested.
A researcher initially captures and marks 50 fish.
Later, they capture 100 fish, of which 25 are marked.
Using the Lincoln Index, estimate the population size.
N = 200 fish
What is a microhabitat?
A small, specific habitat within a larger habitat that has particular environmental conditions and resources.
A bee obtains nectar from a flower while pollinating the flower.
What type of interaction is this?
Mutualism.
Why are pioneer species particularly successful during the early stages of succession?
They are generally able to colonise harsh or disturbed environments, reproduce effectively and tolerate conditions with limited resources.
Put these taxonomic groups in order from broadest to most specific: Species → Family → Kingdom → Genus → Phylum
Kingdom → Phylum → Family → Genus → Species.
A population initially increases rapidly but eventually levels off around 800 individuals.
What type of population growth is this, and what does the value of 800 represent?
Logistic growth, and 800 represents the carrying capacity (K)
A plant species is found mainly in areas with high soil moisture.
Researchers find that abundance increases as soil moisture increases.
What type of factor is soil moisture, and what relationship does the data suggest?
Soil moisture is an abiotic factor. The data suggests a positive relationship between soil moisture and plant abundance.
Define an ecological niche.
The role and position of a species within an ecosystem, including how it uses resources and interacts with biotic and abiotic factors.
Only a small percentage of energy available at one trophic level is transferred to the next trophic level.
Give two reasons why energy is lost.
Energy is lost through:
Two ecosystems each contain 5 species.
Ecosystem A: Each species has approximately the same abundance.
Ecosystem B: One species makes up 80% of all individuals.
Which ecosystem has greater evenness, and why?
Ecosystem A, because individuals are distributed more evenly among the species.
A population begins with 200 individuals. During the year there are 35 births, 20 deaths, 15 immigrants and 10 emigrants.
What is the final population?
200 + 35 − 20 + 15 − 10 = 220 individuals
Researchers want to compare plant diversity across three different vegetation layers in a rainforest.
Which sampling method would be particularly appropriate and why?
Stratified sampling, because the rainforest can be divided into distinct strata and samples taken from each stratum to ensure each habitat is represented.
Two species occupy exactly the same ecological niche and compete for the same limiting resources.
According to the competitive exclusion principle, what is likely to happen over time?
One species is likely to outcompete and exclude the other from that niche, unless resource partitioning or another mechanism reduces the competition.
An ecosystem has a gross primary productivity of 2,400 kJ m⁻² yr⁻¹. Producers use 900 kJ m⁻² yr⁻¹ in respiration.
What is the net primary productivity?
NPP = 1,500 kJ m⁻² yr⁻¹