Biodiversity Flashcards
What does biodiversity refer to?
The variety of living organisms in an area.
Can be considered at different levels:
Habitat biodiversity – number of different habitats in an area.
Species biodiversity – species richness and evenness.
Genetic biodiversity – genetic variation within a species.
Why is biodiversity important?
Ecosystem stability – diverse ecosystems are more resilient.
Economic value – resources for medicine, agriculture, and tourism.
Ecological balance – interdependent species support ecosystems.
Aesthetic and cultural value – natural beauty and well-being.
What is the difference between species richness and species evenness?
Species richness: The number of different species in an area.
Species evenness: The relative abundance of each species.
Both are used to calculate biodiversity in an ecosystem.
What is genetic biodiversity, and why is it important?
The variety of alleles within a species.
High genetic biodiversity allows species to adapt to environmental changes and resist diseases.
What are the two main types of sampling?
Random sampling – Every individual has an equal chance of selection (e.g., using random coordinates).
Non-random sampling – Individuals are selected based on certain criteria:
Systematic sampling – Samples taken at fixed intervals (e.g., along a transect).
Opportunistic sampling – Chosen based on availability (less representative).
Stratified sampling – Dividing a population into groups and sampling proportionally.
What are methods for sampling animals?
Sweep nets – Catch flying insects in vegetation.
Pitfall traps – Catch ground-dwelling insects.
Tullgren funnel – Extracts invertebrates from leaf litter.
Kick sampling – Collects aquatic organisms from rivers.
What are methods for sampling plants?
Quadrats – Measure percentage cover or species frequency.
Point frame – Records species touching the frame.
Transects – Line or belt transects assess change across an area.
How can sampling be made more reliable?
Increase sample size.
Use random sampling to reduce bias.
Repeat measurements and take an average.
What is Simpson’s Index of Diversity?
1 - (Σ n(n-1) / N(N-1))
where ‘n’ is the number of individuals of a particular species, and ‘N’ is the total number of individuals in the sample
Higher values indicate greater biodiversity.
How does the Mark-Release-Recapture method estimate population size?
Capture and mark individuals.
Release them back into the habitat.
Recapture a sample and count marked individuals.
Use the formula:
Populationsize = numberinfirstsample ×
numberinsecondsample/
numberofmarkedrecaptures
