1. BIOLOGY 157: LIFE SCIENCE: AN ENVIRONMENTAL APPROACH (Biodiversity, Niche, Species-Species Interactions)

2. CONSERVATION BIOLOGY, BIODIVERSITY AND ENDANGERED SPECIES
a relatively new multidisciplinary science which deals with the maintenance of ecosystems and their biodiversity
studies human effects on biodiversity and tries to develop practical ways of preserving biodiversity and ecological integrity

3. BIODIVERSITY THREE MAIN COMPONENTS 1) Species Diversity
the number of species in an area
2) Genetic Diversity
the number of genetic strains within a species
3) Ecological Diversity
refers to the complexity and richness of a community (# of niches, # of trophic levels, # of ecological processes)

4. HOW MANY SPECIES? Approx. 1.5 million already described
3 million is a minimum number
some estimate 30 to 100 million
(probably a gross overestimate)
5 to 10 million
(a more reasonable estimate)
new species discovered all the time, especially in understudied areas such as rainforests, soil, deep sea and in incompletely studied groups such as fungi, insects, mites, and nematode worms

5. REASONS FOR PRESERVING BIODIVERSITY
Aesthetics / Recreation / Health
Cultural-Historical Knowledge
Scientific Knowledge (Should this be a separate listing?)
Economic
Ecosystem Stability

6. WHAT CAUSES SPECIES TO BECOME ENDANGERED / THREATENED / EXTINCT
Over Exploitation
(too much hunting, harvesting, collecting, etc.)
Toxics in the ecosystem
Habitat Alteration / Destruction / Fragmentation
(farming, grazing, logging, introduction of EXOTIC species (Dutch Elm Disease, Zebra Mussels, Japanese Beetle, Water Hyacinth)
ENDEMIC SPECIES ?
EXOTIC SPECIES ?

7. HOW TO SAVE / PRESERVE THE BIOTA?
need to treat the biota as a ‘COMMONS’
need more centralization / coordination of preservation and management efforts
must have suitable habitat of sufficient size
Island Biogeography
suitable habitats must be assisted in their recovery or constructed from scratch
Germplasm Banks
- Zoos and Botanical Gardens
- True Genetic Banks
› Seed Banks
› Sperm, Ova, and Embryo Banks
› DNA Banks

8. THE FATE OF SPECIES
It is the ultimate fate of all species to become extinct.
There is a limit to the number of species / genetic strains that can be preserved.
Species may have attributes that make them more OR less likely to become threatened / endangered / extinct. Examples:

9. THE ECOLOGICAL NICHE
We have all probably used the term ‘niche’ before.
What does it mean?
DEFINITION:
A multidimensional concept which defines a species “place” in a community in relation to other species.
It is more than just the physical place (‘address’) where a species lives, it also includes its role (‘occupation / lifestyle’).
Thus the Ecological Niche is a multidimensional concept which includes where an organism lives AND also includes what it does, how it does it, when it does it, etc. It is its total role in the ecosystem.

10. TYPE OF NICHE Fundamental or Hypothetical
the total range of physical, chemical and biological factors a species can utilize / survive if there are no other species affecting it
Realized or Actual
that portion of the fundamental niche that a species actually uses.
Species never live under ‘perfect’ conditions but where an ‘acceptable’ ECOLOGIC SUM of conditions exists.

11. NICHE EXCLUSION PRINCIPLE (= Competitive Exclusion Principle) (= Gause’s Law)
DEFINITION: In normal communities two species cannot occupy the same niche for any length of time.
It follows logically that no two species can coexist if they need all the same things in the same place, at the same time, etc.)
The greater the degree of niche overlap, the greater the competition for scarce resources AND the more likely one species will eliminate the other.

12. GAUSE & PARAMECIUM (too much niche overlap)

13. LIMITING NICHE OVERLAP (I)

14. LIMITING NICHE OVERLAP (II)

15. LIMITING NICHE OVERLAP (III)

16. INTERSPECIFIC INTERACTIONS
Neutral Interactions
none of the interacting species is affected by the others
Is this really possible???????????
Positive Interactions
at least one of the interacting species is benefited and the other(s) is (are) not harmed
Negative Interactions
at least one of the interacting species is harmed during the interaction

17. Positive Interactions (I)
Commensalism
one species is benefited and the other(s) is (are) not affected
without continuous contact : Vulture / Predator
with continuous contact: Turtle / Alga
Protocooperation
both species are benefited BUT the relationship is NOT obligatory
without continuous contact: Squirrel / Oak Tree
with continuous contact: some Mycorrhizae (a fungus / plant root relationship)

18. Positive Interactions (II)
Mutualism
both species are benefited AND the relationship IS obligatory
without continuous contact: many Pollinator / Plant relationships
with continuous contact:
Termites / Protozoans Humans / E. coli Lichen (alga / fungus)? most Mycorrhizae (fungus / plant root relationships)

19. NEGATIVE INTERACTIONS (I)
Competition
both species are harmed during the interaction
Imperfect
neither species is eliminated but one or both are reduced in number (some niche overlap)
Pontin’s work with 2 species of ants of the genus Lasius
Perfect
one species is eliminated (too much niche overlap)
Gause’s work with 2 species of Paramecium

20. NEGATIVE INTERACTIONS (II)
Predation
one is helped (fed) --- one is harmed (eaten);
a direct attack in which one species (the predator) benefits by killing and eating another (the prey)
Wolf / Deer
Are both helped??????
Parasitism
one is helped (fed) --- one is harmed (weakened);
a direct attack in which the parasite benefits by taking small quantities of materials from its host over an extended period of time and generally does not kill the host.
Tape Worm / Human