1. Ecology: Human Impact & Conservation
IB Biology
G3 & G4

2. Numbers of individuals
Biological Diversity
Biological Diversity: Evenness and Richness
Richness: the number of different organisms in a particular area (kinds of species)
Evenness: how the quantity of each different organism compares to the others (abundance of kinds of species)
Numbers of individuals
Flower Species
Sample 1
Sample 2
Daisy
300 20
Dandelion
335 49
Buttercup
365
931
Total
1000
Is a community diverse if it is dominated by a single species? Why/why not?

3. Simpson Diversity Index
A measure that takes into account richness and evenness
Formula: D =
Where:
D = diversity index
N = total number of organisms in the ecosystem
n = number of individuals of each species
N (N-1)
sum of n (n-1)

4. Simpson Diversity Index Example
Species
Number (n)
n(n-1)
Woodrush 2
Holly (seedlings) 8 56
Bramble 1
Yorkshire Fog
Sedge 3 6
Total (N) 15 64
Σ n(n-1)
D = 15 (14) 64
D = 3.3
What does this number represent? How can it be used?

5. Reasons for Conserving Biodiversity
Economic
Examples: rainforest soils for crops; pharmaceuticals; ecotourism
Ecological
Loss of diversity could collapse the ecosystem; diversity makes ecosystems less susceptible to invasive alien species; diversity of plant species buffers the effects of increasing greenhouse gasses
Ethical
“We do not inherit the earth from our ancestors, we borrow it from our children” Native American Proverb
Aesthetic
Nature’s beauty inspires art, gives us awe, and is connected to human cultures in countless ways

6. Biological Control
The use of an organism (introduced) to control another organism
Risks: introduced organism may not behave as expected (Cane Toads)
Benefits: introduced organism may be the only control mechanism flexible enough to be effective against another invasive with no predators
Examples
Purple loosestrife (invasive in US and Canada) – controlled by 2 species of beetles (Gallerucella)
Red Invasive Fire Ants (RIFA) (invasive on many continents) – controlled by Phorid flies
red fire ants and phorid flies video on NG.com

7. Biomagnification
The process by which chemical substances become more concentrated at each trophic level.
[Increase]: 10 million times

8. CFCs and Ozone
In the atmosphere, CFCs (used in refrigerator coolants, propellants, and foam packaging) release chloride ions.
The chloride ions react with ozone (O3) and produce ClO and oxygen gas (O2)
The ClO molecules react with atoms of O to form more O2 and free up the Cl
In this way the CFCs behave like a catalyst that doesn’t get used up and is free to destroy ozone for a century
Depleted ozone layer permits more UV radiation through the atmosphere
UV radiation causes:
Skin cancer, DNA mutation, sunburn, cataracts, reduced biological productivity, and may be related to loss of amphibian biodiversity globally

9. Indicator Species AKA “the canary in the coal mine”
Organisms sensitive to environmental conditions
Examples: Lichen (air pollutions like lead/mercury), macroinvertebrates (water quality)

10. http://www. people. virginia. edu/~sos-iwla/Stream-Study/Methods/Form
Biotic Index

11. Biodiversity in a Nature Reserve
Size of the Reserve
Single large or several small sites? Single large better because small sites = small populations (greater chance for extinctions from disease/lack of genetic diversity). Small sites also have more edges (see next). Some organisms have require large territories that can’t overlap.
Edge Effect
Ecology at the edge of an ecosystem is different from the center. Edges can have more sunlight, more wind, less moisture, and fewer trees. Edge organisms may have more competition/fewer resources. Edges are more susceptible to invasive species.
Corridors
Smaller, otherwise isolated habitats, connected by corridors allow organisms to travel between them. Problems include exposure in narrow corridors, invasives, and human/animal interactions around corridors.

12. Management in Conservation Areas
Restoration: attempt to return the land to it’s natural state through various active management techniques
Recovery of threatened species: usually through habitat restoration (which helps all species ,declared threatened or not, who occupy the habitat)
Removal of introduced species: active removal of invasives such as kudzu from the US southern states or leafy spurge in the US western states
Legal protection against development/pollution/hunting
Funding and prioritizing: limited funding creates the need to make choices:
Restore the habitats of all threatened species or just the ones that make the greatest overall impact?
Remove all introduced species, or just invasives?

13. In Situ Conservation
Conservation of species within their natural habitat (where they belong), such as wildlife reserves, national parks, etc…
Includes planning for improvement of biotic and abiotic factors of that habitat
Maintaining habitat (space); defense of target species from predation; removal of invasives; maintaining large populations; maintaining genetic diversity
Allows threatened species to adapt to environment with minimal interference from humans or invasives
Terrestrial reserves are common for in situ conservation, but marine aquatic reserves lag far behind

14. Ex Situ Conservation
Conservation of a species outside of their natural habitat
Necessary if species is unsafe in the natural habitat, has a population too small to make a come-back, or if social/political/economic reasons make habitat protection impossible
Examples:
Captive Breeding Facilities
Botanical Gardens
Seed Banks

15. Captive Breeding
Zoos are the most common, most have large sections dedicated to captive breeding programs, animal husbandry experts, and money from tourism
Techniques
Artificial insemination (when necessary)
Embryo transfer to surrogate mothers
Cryogenics
Human-raised young (when necessary)
Pedigrees (to reduce inbreeding)
Disadvantages:
Captivity-bred organisms can spread disease to wild ones after re-introduction
Captivity-bred organisms lack the in situ learning and survival strategies

16. Botanical Gardens and Seed Banks
80,000 plant species kept in private gardens, arboretums and botanical gardens all over the world to protect and breed them
Far easier to care for plants than to breed animals
Problem: wild relatives of commercial crops are under-represented. Genes from these plants could infuse longevity into traditionally inbred crop plants (i.e. bananas)
Seed banks are keeping 10,000 to 20,000 plant species seeds in cold, dark conditions to prevent germination (for decades).