Unit 2: Ecology and Biodiversity Flashcards
3 Scales of Biodiversity
- Genetic Variation
- Species Diversity
- Habitat/Ecosystem Diversity
Would high or low genetic diversity enable a population to have more resilience after environmental stress/disturbance?
High genetic diversity; It is more likely there are advantageous genes present that will protect individuals and give them a better chance of survival.
Bottleneck Effect
A drastic and sudden reduction in the size of a population; leads to change in gene pool
What defines a species?
Ability to breed and produce offspring effectively
Why is species diversity considered a critical environmental indicator?
When species are more diverse, their likelihood of survival increases because they have more opportunities to survive.
Generalist Species
Species that can live under a wide range of biotic/abiotic conditions
Specialists Species
Live under very narrow range of conditions or feed on one or very small group of species
How would habitat loss effect specialists vs generalists?
Specialists: impact very negatively because limited opportunity of survival
Generalists: wouldn’t effect as poorly because able to survive off of wider range of resources
Species Richness
Number of total species
Species Evenness
Abundance of individuals within each species
Simpsons DIversity Index
D = N (N - 1) / SUM n (n - 1)
N = total number of individuals collected
n = numbers of individuals of a species
4 Types of Ecosystem Services
- Provisioning
- Regulating
- Support
- Cultural
Provisioning
Goods that humans use
Lumber, crops, rubber, fur, medicinal plants
Regulating
Helps regulate environmental conditions
Nutrient and water cycles
Support
Needed to support and maintain services
Pollination, water filtration
Cultural
Aesthetic uses
Tourism, real estate, recreation
Intrinsic vs Instrumental value
Intrinsic: moral/spiritual/religious/philosophical
Instrumental: has worth in terms of goods and services
Island Biogeography
Study of the ecological relationships and distribution of organisms, and of these organisms’ community structures
Natural vs anthropogenic ways of new species colonization on islands
Natural: swimming, storms, flying, riding other organisms
Anthropogenic: boats, purposeful bringing
Are most island species specialists or generalists?
Specialists, this makes them more vulnerable to invasive species.
Theory of Island Biogeography
Increased species richness usually indicates a bigger island size
Ranges of Tolerance
Populations thrive within certain ranges of abiotic factors
Zone of Intolerance: NO SPECIES
Zone of Stress: FEW SPECIES
Optimal Range: SPECIES ABUNDANT
Limiting factors
Environmental factors that are most often in short supply
Resistance vs Resilience:
Resistance: Ability to remain unchanged when being subjected to disturbance
Resilience: Ability and rate to recover from disturbance and return to pre-disturbed state
Intermediate Disturbance Hypothesis
Ecosystems require certain levels of distribution for maximum health and diversity
What makes modern-day change, with anthropogenic causes, different from all the previous natural change?
Frequency and Intensity
Fitness vs Adaptation
Fitness: Differential ability to survive and reproduce
Adaptation: Any behavioral or physical characteristic that increases fitness
4 Points of Natural Selection
- There is a struggle for existence among organisms
- There is physical/behavioral variation in living organisms
- Organisms with higher fitness are more likely to survive (survival of the fittest)
- Over time, natural selection will cause certain characteristics to appear more often as they are passed through generations
When faced with environmental condition changes, populations may:
M: Migrate to more favorable conditions
A: Adapt
D: Die
How does climate change effect evolution?
Ice age, global warming perceived as cause for migration, extinction, new niches
Primary Succession
Starts with airborne lichen on bare rock
Secondary Succession
Starts with grass because already has base from primary succession. Occurs much faster
Keystone species
Animals that have bigger impact on their ecosystems than others.
What happens when you lose keystone species?
Food webs and nutrient cycles disrupted, population crashes, eventual extinction
Trophic Casade
Impact every trophic level exponentially (think of wolves at Yellowstone)
