1. History and meaning of the word “Ecology”
Definition
Oikos, ology - the study of the house - the place we live
Etymology – study of the origin and development of a word
Earliest - Haeckel (1869) - comprehensive science of relationship of organism and environment
Elton (1927) - scientific natural history
Andrewartha (1961) - Scientific study of the distribution and abundance of organisms
Krebs (1985) - scientific study of the interactions that determine the distribution and abundance of organisms
Note that all talk about “scientific”
Why???
Separation of induction (natural history) and deduction (scientific method)

2. Definitions (levels of ecological organization)
Individual (can be difficult to define! Generally, a biological organism that…)
Lives, reproduces, dies
Has a unique genotype
Is the unit of selection
Is autonomous of other organisms
Population (a collection of individuals in an area, of the same species, that…)
Interact with one another
Interbreed
Species (characterized by…)
Individuals, naturally capable of interbreeding and producing fertile offspring
Community
A group of populations (species) in a given place - usually implies that populations (species) interact
Ecosystem
A biotic community and its abiotic (physical) environment

3. Basic Population Biology
Basic Population Biology - losses may matter
Basic Population Biology
100 20 40 60 80
Population
Time K

4. Basic Population Biology-
Unlimited Growth = Malthusian Growth or exponential growth
Logic:
Population at time t = Nt
Population at time t + 1= Nt+birthrate (b) + immigration (i) + emigration (e)+ death rate (d)
Where t= time t and t+1= sometime after that

5. Exponential Growth r = b-d Assumptions:
Basic Population Biology - losses may matter
Exponential Growth
Assumptions:
1) Emigration = immigration, then
Nt+1 = Nt+births (b) - deaths (d)
where b and d are instantaneous estimates
2) Generations overlap
3) Resources are unlimited
Now let the instantaneous per capita rate of growth (r) equal the birth – death rate:
r = b-d

6. Exponential Growth - calculation
Basic Population Biology - losses may matter
Exponential Growth - calculation
Births > Deaths
r > 0
Nt = N0ert
N0 = population at time 0
r= per capita rate of growth (b – d)
t= time
e= base of the natural log (~2.72)
100 80 60 40
Population
Essentially same formula as compounded interest 20 20 20 40 40 60 60 80 80
100
100
Time

7. Exponential Growth - calculation
Basic Population Biology - losses may matter
Exponential Growth - calculation
Births < Deaths
r < 0
Nt = N0ert
N0 = population at time 0
r= per capita rate of growth (b – d)
t= time
e= base of the natural log (~2.72)
100 80 60 40
Population 20 20 20 40 40 60 60 80 80
100
100
Time

8. Exponential Growth – an Understanding of Rates
Basic Population Biology - losses may matter
Exponential Growth – an Understanding of Rates
Let r =
0.20
0.10
0.05 N t
Rate of growth
of population =
100 N t
High population size (N),
population growth rate is
high because
rN = large value
Low population size (N),
population growth rate is
low because
rN = small value 80
Using calculus we can derive
a function for the instantaneous
rate of growth of populations.
The rate of change of the
population is equal to
growth rate x the population
dn / dt = rN 60
Population 40 20 20 20 40 40 60 60 80 80
100
100
Time

9. Exponential Growth - why is growth unlimited?
Basic Population Biology - losses may matter
Exponential Growth - why is growth unlimited?
The assumption is that the per capita growth rate (r) is unrelated to population size (N). This means:
1) Birth rates are unaffected by population size, and
2) Death rates are unaffected by population size
Does this make sense?
Birth rate (b)
remember r = b - d
Per capita growth rate (r)
Death rate (d)
Population (N)
Population (N)

10. Per capita growth rate (r)
Basic Population Biology - losses may matter
Limited Growth
Assumptions:
1) Resources become limited as populations increase
Thus, per capita rate of growth must decrease with increasing population
Per capita growth rate (r)
Resources
Population (N)
Population (N)

11. Per capita growth rate (r)
Basic Population Biology - losses may matter
Limited Growth – caused by changes to birth and death rates that are density dependent
Per capita growth rate (r)
Birth rate
Death rate
Population (N)
Rate
Population (N)

12. Limited Growth – density dependence
Basic Population Biology - losses may matter
Limited Growth – density dependence
Exponential rate of population
growth 20 40 60 80
Population
100
Time
K= carrying capacity K
dn / dt = rN
Logistic (limited) rate of population growth
dn / dt = rN
(K-N) K
100

13. Key consequence of density dependence:
Population regulation: when population fluctuations are bounded so as not to increase indefinitely or decrease to extinction 20 40 60 80
Population
100
Time ? ?
100

14. Logistic (limited) growth – implications for conservation I
Basic Population Biology - losses may matter
Logistic (limited) growth – implications for conservation I
Excess Adults
K / 2
Adult Population
Population Growth Rate
100 20 40 60 80
Population
Time K
Excess
Maximum K

15. Logistic (limited) growth – implications for conservation II
Basic Population Biology - losses may matter
Logistic (limited) growth – implications for conservation II
Excess Juveniles - Compensation 20 40 60 80
Population
100
Time
Excess K
Adult Population
100
Juveniles

16. Excess or Resource – should the buffers be given away?
Basic Population Biology - losses may matter
Excess or Resource – should the buffers be given away? K
K / 2
Maximum
Excess
Excess
Population Growth Rate
Adult Population K
Adult Population
Juveniles

17. Excess or Resource – should the buffers be given away?
Basic Population Biology - losses may matter
Excess or Resource – should the buffers be given away?
Provides buffer for cumulative effects
Provides buffer for natural and anthropogenic impacts K
Adult Population
Population Growth Rate
K / 2
Maximum
Buffer
Buffer
Adult Population K
Juveniles

18. Basic questions are:
1) Do density-dependent processes produce excess individuals (that are essentially wasted) or population buffers that provide a safety mechanism against
I) Natural variability
II) Natural disturbances
III) Additional anthropogenic impacts
2) Are population (demographic) buffers the property of the general public or industry?
3) Example: fish losses due to fishing (adults) and power plant entrainment (larvae)

19. Population Structure:
Contrary to assumptions of Logistic Growth, not all individuals in a population are the same!
Structure: relative abundance of individual traits among individuals in a population:
i) size
ii) age
iii) stage (e.g., larvae, juveniles, adults)
iv) sex
v) genetic (distribution of genotypes throughout population)
vi) spatial (distribution and interaction of individuals within and among populations)
All of these influence per-capita rate of mortality (D) and reproduction (B)

20. Size Matters: Bigger Fish Produce Far More Larvae
Approx. 7-fold
increase
Approx. 11-fold
increase

21. Fished population
Non-fished population

22. black rockfish (Sebastes melanops).
Age matters: older females produce higher quality larvae
with a higher likelihood to survive
Larval growth
in length
(mm/day)
Time (d)
to 50%
larval mortality
Berkeley et al
Fisheries 29:
Berkeley et al
Ecology 85:
Maternal age (yr)
Moreover: Different aged fish spawn at different times
Bobko, S. J. and S. A. Berkeley Fishery Bulletin 102:

23. Key consequence of density dependence:
Population regulation: when population fluctuations are bounded so as not to increase indefinitely or decrease to extinction 20 40 60 80
Population
100
Time ? ?
100

24. “Bipartite” life cycle of benthic marine organisms with pelagic larvae
survive, grow, develop, disperse
Pelagic Environment
reproduce
settlement
Benthic Environment
One key life history trait characteristic of many marine fishes is what fish heads refer to as a “bipartite” life cycle, in which
Different life stages are adapted for life in either the benthic and pelagic environment.
BUT “CLOSED” cycle is misleading…
Adult
Juvenile
survive, grow, mature

25. “Bipartite” life cycle of benthic marine fishes with pelagic larvae
For those species Young produced by adults in a local population

26. “Closed” Populations “Open” Populations
Production
Supply
Production
Supply
Little or no exchange among populations
Significant exchange among populations
Production
Supply
Supply
Production

27. Spatial structure of populations
implications for gene flow, genetic diversity and population persistence
“Closed” populations: self-replenishing
Limited dispersal: stepping-stone
Single source: mainland - island
Multiple sources: larval pool
LARVAL POOL

28. Spatial structure creates “metapopulations”
Collection of isolated self-replenishing sub-populations
Collection of highly connected sub-populations
Mostly self-replenishing
Separate dynamics
No “rescue effect” from other sub-populations
Persistence based only on local sub-population size and processes, density-dependence, independent of other sub-populations
Little self-replenishment
Sub-populations with very similar dynamics
Highly influenced by “rescue effect” from other sub-populations
Persistence based largely by system-wide dynamics and processes, especially the number of connected sub-populations

29. Spatial structure creates “metapopulations”
Metapopulation: collection of partially-connected sub-populations
Some self-replenishment, some external replenishment
Variation in sub-population dynamics (asynchronous)
Influenced by “rescue effect” from other populations
Persistence based on both local and system-wide dynamics and processes, especially the size and number of sub-populations, and density-dependence

30. Population Attributes
Life History Traits
(individual, heritable, species-wide)
reproductive modes
longevity, fecundity
life cycle
Population Attributes
distribution
structure (size, age, genetic, spatial)
dynamics
One of the most fascinating aspects of ecology, and a central focus of evolutionary ecology, is understanding the ecological consequences of life history traits.
These are heritable traits characteristic of a species, such as longevity… , that can influence the distribution, structure and dynamics of populations…
Community Attributes
biogeography
structure (composition, abundance)
dynamics
diversity