Unit 3 Flashcards
Define biodiversity
The variety with regards to both species and ecosystems within a given habitat
- Higher diversity is more desirable (more successful species, complex food webs, environmental change less likely to have damaging effects on whole ecosystem
Define/describe biotic and abiotic factors
Biotic - living organisms within and that affect ecosystem (eg. Humans, plants, bacteria, diseases, predators)
Abiotic - non-living physical and chemical factors that influence organisms and ecosystem (eg. Climate, sunlight, humidity, shelter, pollutants)
List measures of species diversity
Species richness, relative species abundance (evenness), percentage frequency, percentage cover, Simpson’s Diversity Index
Explain species richness
- Number of different species in ecosystem
- Does not take into account populations of each species or evenness of species
Explain relative species abundance
- Measure of how un/common species is relative to its surroundings (evenness)
- Can compare the abundance of different species between 2 areas
- Places population of a species in context of its environment, shows concentration of population in particular ecosystem
Explain percentage frequency and percentage coverage
- Use quadrats to sample
- % frequency measures probability that species will be found in a single quadrat
- % cover tells how much space a species occupies
%freq. = (no. quadrats in which the species is found)/(total no. quadrats) × 100%
Explain Simpson’s Diversity Index
- Accounts for both species richness and evenness
- Probability that 2 randomly selected organisms will be different species
- Number between 0 and 1, where 0 indicates no diversity, and 1 indicates infinite diversity
SDI=1−(Σn(n−1))/(N(N−1))
(where N = total no. organisms of all species, and n = no. organisms of target species)
Define spatial vs temporal scale, in reference to comparing ecosystems
Spatial scale - shows distance between habitat patches
Temporal scale - changes in ecosystem over time
Define symbiosis
- Long-term interaction between two species living in physical proximity
Describe types of species interactions (symbiosis)
- Predation - predator benefits, negative effect on prey
- Competition - negative effect on both species
- Mutualism - benefits both species
- Neutralism - no effect on either species
- Amensalism -negative effect on one species, and no effect on other
Commensalism - benefits one species, and no effect on other
Describe abiotic factors used to compare ecosystems across spatial and temporal scales
- Climate (includes temperature, weather patterns)
- Substrate - surface or substance where organisms live (eg. Fresh water creeks, in undergrowth and moss of rainforest, in ocean, etc.) - provides info about nutrients and composition of environment
Size/depth of area - how much space does the ecosystem occupy (important when examining populations affected by deforestation, coral bleaching or other destructive events that drastically reduce available space for ecosystems)
Explain how environmental factors limit the distribution and abundance of species in an ecosystem
How are organisms classified?
- Morphology - physical shape/structure
- Reproduction - eg. Asexual and sexual reproduction
- Molecular characteristics (genetic)
Explain the Linnaean system of classification
- Hierarchical structure
- Primarily uses morphological features
- Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
- Domain is most broad classification group, and species is most specific
Explain molecular sequencing/molecular homology in regards to classification of organisms and cladistics
- Determine how similar the DNA base sequences are between two species –> more differences in base sequence, more distantly related
