1. The Niche
American oystercatcher prying limpet off a horseshoe crab

2. Hutchinson’s Niche Definitions
The fundamental niche - the set of resources and conditions that permits the survival and reproduction of an organism - many resources and conditions interact to form the niche.
The realized niche - the portion of the fundamental niche actually occupied by the species when restricted by other organisms - restricted by competition, predation, parasites, disease.
- Hutchinson 1958

3. Fundamental vs. Realized Niche

4. Key point – two species cannot have identical niche

5. Populations

6. Populations
Population - a group of organisms of the same species which have the potential to interbreed – or a population is a group of organisms of the same species occupying a particular place at a particular time
Populations have a number of properties which are not possessed by individual organisms - this is because a population is the sum of many organisms interacting

7. Starling Murmuration

8. Population Dynamics Properties of populations Size Density Dispersal
Emigration
Immigration
Births
Deaths
Survivorship

9. Population Boundaries

10. Density and Distribution

11. Prairie Dog Distributions

12. Prairie Dog Colonies

13. Cormorant Nesting - Patagonia

14. Properties dealing with changes in population size
Natality - may think of this as births, but includes more than just birth - hatching, germination, fission
Natality includes idea of fecundity - number of offspring produced per unit time - we are most concerned with realized fecundity - actual number of survivors
Mortality - death rate - its converse is survivorship - mortality looks at how many die per unit time, survivorship at how many don't die per unit time
Longevity examines life-span of individuals - again we are most interested in realized longevity, not potential longevity
Immigration - individuals moving into a population
Emigration - individuals leaving a population

15. Changes in human longevity - life expectancy at birth

16. Typical animal life spans

17. What is an individual?
unitary organism - individuals are highly determinate in form and while growing pass through predictable (innately determined) sequences of life history stages
modular organisms - zygote develops into unit, or module, which produces more modules asexually thus producing an organism with a variable number of modules, whose development is unpredictable and strongly influenced by environmental factors

18. A classic unitary organism

19. A classic modular organism
Bryozoan colony

20. Freshwater Bryzoan

21. More classic modular organisms

22. Genets and Ramets
ramet - a module with the potential for a separate existence
genet - the "genetic individual"; the collection of all modules derived from a single zygote

23. A single Aspen clone

24. Posidonia oceanica – Neptune grass

25. Sampling to collect population data
Census - most basic sampling - count and determine age of all individuals in population, count again later
Several ways to subsample and estimate population size:
1. Determine total area in which population occurs, count all individuals in small plots, multiply average number in plots to get total, repeat at later dates - works best for sessile organisms
2. Mark-recapture methods
3. Catch per unit effort
4. Miscellaneous methods – traps, counts of fecal pellets, counts of vocalizations, feeding damage on plants, radar counts, roadside sightings, fur or pelt records, roadkill

26. Quadrat Sampling

27. Mark recapture of Cicadas

28. Catch per unit effort – Pacific Threadfin

29. Beetles feeding on Viburnum

30. Beetle damage on Viburnum

31. Bird migration data – typical altitude – from radar

32. Bird migration radar map

33. Skylark

35. Metapopulations
A metapopulation is a series of small, separate populations united together by dispersal

36. Metapopulation Dynamics

38. Metapopulations of Bay Checkerspot Butterfly

39. Bay Checkerspot
Jasper Ridge

40. Aphids and Epilobium

41. Habitat fragmentation in Amazonia