Lecture 21: Applied and Large-Scale Ecology Flashcards
Biodiversity
- The diversity of important ecological entities that span multiple spatial scales, from genes to species to communities
1. Genetic diversity within a species - morphological/ phenotypic diversity
Diversity within colour starfish)
2. Species diversity within a community
3. Diversity of communities across landscapes
Example of Biodiversity
- Without the interaction between Corals & Symbiodinium we not have biodiversity within an ecosystem
- Within this bond they make coral reefs/ communities
Why should we care
- Protecting biodiversity is important for both practical and moral reasons
- We are dependent on ecosystem services
The following functions depend on the integrity of natural communities and ecosystems
- Water purification
- Generation and maintenance of soils
- Pollination of crops
- Climate regulation
- Flood control
- Source of food… like fish
Why is Biodiversity Declining Globally
- endangered
- extinct
Estimates of Current Extinction Rates Rely On
- The species–area relationship
- Changes in the threat status of species
- Rates of population decline or range contraction of common species
- Extinction is normal
- See a speciation event and then after so much time that species will disappear
- humans have been causing extinctions for years, species dramatically decline when humans show up
Rate of Extinction
- difficult to measure
- since the # of species on Earth currently is unknown
- estimated from the fossil record are used as background rates
- Most species are headed to extinction
Mammals and Birds
background rate is one species every 200 years
Current Extinction Rate
1 per year
Overall Extinction Rates
100-1,000x higher than the background rate
Primary Threats to Biodiversity
habitat loss !!!
Habitat Loss
- Conversion of an ecosystem to another use
- Habitat loss if the primary threat to biodiversity– needs to be conserved
- Humans have modified 60% of earth’s land surface, now appropriating 25% of Earth’s primary production
Habitat Fragmentation
Breaking up continuous habitat into patches amid a human-dominated landscape
Habitat Degradation
Changes that reduce quality of the habitat for many, but not all, species
Overexploitation
- Size of cod has been shrinking due to overfishing
- Areas of the landscape change
- 1870 american bison skulls were ground into fertilizer
- Animals are overexploited for many things that aren’t food
Pollution
- PCB can cause species to be more vulnerable to diseases, and can compromise an immune system
- PCB accumulates throughout a food web (high amounts in killer whales who are at the top of the trophic level)
- Has its impact on wildlife, see chemicals make their way to humans
Disease
- As populations become smaller they become more susceptible to diseases
- Inbreeding, heterozygosity
Extinction Vortex
- A cyclic chain of events causes a small population to decline even further and become ever more vulnerable to processes that lead to extinction
Invasive Species
- a nonnative organism introduced to an new environment and has the potential to cause harm to the environment, economy, or human health.
- Ex. buckthorns wipe out the local flora in local areas and they change the species that feed on certain plants
- Marine environment is affected by the european green crab- boats spread the larvae of this green crab all over the world (causing green crabs to be everywhere)
Climate Change/ Crisis
- Polar bears: loss of ice ecosystems in arctic
- Corals: bleaching of corals, UV radiation, lowering of pH, makes corals more fragile
- Ocean acidification
Ocean Acidification
lowering of the PH and skeletons made of calcium carbonate break down in acidic conditions
