Stratified Sampling
Question: Define stratified sampling and give an example of a habitat where it would be more accurate than random sampling.
Answer: Stratified sampling divides a habitat into subgroups (strata) based on specific features, with samples taken from each. It's useful in heterogeneous habitats, such as coastal areas with distinct tidal levels.
Question: What is carrying capacity in an ecosystem?
Answer: Carrying capacity is the maximum population size an environment can sustainably support, given its resources.
Question: What are the two main criteria for classifying vegetation using Specht’s classification?
Answer: Vegetation height and canopy cover percentage.
Question: Write the formula for Lincoln’s Index.
Answer: N= M x n / m
My family has 3 creatures named after them, can you name one of them?
Dicksonia Antarcticus (Fern), Dicksonia (Thylacine), Dicksonia (Snail) - Named after me!
Question: Why might ecologists choose stratified sampling over random sampling in a forest ecosystem with multiple canopy layers?
Answer: Stratified sampling ensures each layer (canopy, mid-story, understory) is represented, as random sampling might miss certain layers and give an incomplete picture of biodiversity.
Question: Name two factors that influence an ecosystem’s carrying capacity.
Answer: Food and water availability, space, competition, predation, and habitat quality all influence carrying capacity.
Question: How would you classify a vegetation zone with tall trees and 70% canopy cover according to Specht’s system?
Answer: This would be classified as a "closed forest" due to the dense canopy cover.
Question: What does Lincoln’s Index estimate?
Answer: It estimates the total population size of a species within a specific area.
What is the worst shark movie of all time?
The Meg 2 (Sharknado at least made me laugh)
Question: How would you set up a stratified sampling study for plant species in a park with three distinct areas: grassland, shrubland, and forest?
Answer: Divide the park into three strata (grassland, shrubland, forest), calculate each area’s proportion, and sample accordingly to gather representative data.
Question: Describe what might happen to a population that exceeds its carrying capacity.
Answer: The population may face resource shortages, leading to competition, a die-off, or migration, reducing the population back to or below carrying capacity.
Question: In Specht’s classification, what canopy cover percentage defines an “open forest”?
Answer: An open forest typically has a canopy cover of around 30-70%.
Question: You mark 60 fish in a pond. Later, you capture 100 fish, 15 of which are marked. Estimate the population using Lincoln’s Index.
Answer: Substitute into the formula:
The estimated population size is 400.
Two truths one lie.
I have never been to New Zealand?
I have been bitten by a brown snake?
I have a twin sister?
I have never been to NZ!
Question: If a habitat has three zones with different sizes (50%, 30%, and 20%), and you’re using 200 sample points, how would you distribute them?
Answer: Allocate 100 samples to the largest zone (50%), 60 to the second largest (30%), and 40 to the smallest (20%).
Question: In a forest study, if deer populations exceed carrying capacity, what changes might you observe in the ecosystem?
Answer: Overgrazing and vegetation loss could occur, impacting plant diversity, leading to soil erosion, and potentially affecting other species relying on those plants.
Question: How might a woodland differ from a shrubland in Specht’s classification system?
Answer: Woodlands have taller trees and often higher canopy cover, while shrublands consist of shorter, bushy plants with lower canopy coverage.
Question: If only 5 marked animals are recaptured in a study, what might this suggest about the population or marking method?
Answer: A low recapture rate could suggest the population is large or that the markings wore off, making it harder to identify previously marked animals.
What is my favourite movie of all time?
Jurassic Park
Question: What are the main challenges of stratified sampling when studying mobile species, and how can these be mitigated?
Answer: Mobile species may move between strata, skewing results. Researchers can address this by tagging animals or adjusting sampling times to better account for movements.
Question: What could cause the carrying capacity of a habitat to decrease over time?
Answer: Environmental degradation, habitat loss, pollution, or increased predation could reduce available resources and lower carrying capacity.
Question: Explain how Specht’s classification could help ecologists understand biodiversity in a national park.
Answer: By classifying vegetation, ecologists can assess habitat types, predict species distributions, and monitor biodiversity changes across different vegetation zones.
Question: Describe two factors that could influence the accuracy of a population estimate using Lincoln’s Index.
Answer: Population movement, marking durability, or changes in population size between samples can all impact accuracy.
What first nation people do my family belong to?
Yugambeh people, south of the albert river.