1. Populations

2. are they in the same population?
…if a Strongsville duck breeds with a Brunswick duck…
are they in the same population?

3. Populations are reproductive groups….

4. …all the members of a species living in the same place at the same time.

5. Even

6. What do you think
is the dispersal of this population?

7. Growth rate
Births
Deaths
Changes in
population
size - =

9. Reproductive Potentialvs

10. Reproductive Potential
The maximum number of offspring that each
member of a population can produce.

11. RP increases when: …individuals produce more offspring at a time…
…reproduce more often…
…reproduce earlier in life.

12. OR:

13. The amount of variation that is present in biological systems makes predicting their growth difficult. However, there are some systems which have been successfully modelled and for which there are equations that permit us to make predictions.

14. Exponential Growth
A larger number is added over time than in the previous time period…
…occurs in populations with enough food & space and without competition or predators…
…a “J-shaped” curve.

15. Carrying capacity: max. pop. that an ecosystem can support indefinitely.

17. Environmental Resistance (aka limiting factors)
Biotic & abiotic factors that may limit a population’s increase!
Lack of food...water... nutrients... or habitat
Predators...disease...parasites...competitors
Whether a population increases, decreases or stays the same is a result of interplay between environmental resistance & reproductive potential

18. Limiting resource
Determines K for a given species in a given area

19. Reproductive Strategy
r-selected
Massive numbers of young
...but leave survival to whims of nature
Smaller orgs, mature early, short life spans
Successful in unstable systems
k-selected
Few offspring
...lots of parental care
Larger orgs, late maturity, long life spans
Adapted to stable systems

20. Population density plays a part!
Density dependent
Factors which are more influential as populations get bigger
Disease... competition...
predation...
parasitism...
Density independent
Factors not influenced by population size
Flood...
fire...
hurricanes...
oil spills...
pesticide use

23. Have you learned about…
…the Chernobyl in 1986?

24. Chernobyl
Crews were testing steam turbines with the safety systems turned off
Steam explosion blows 1000-ton roof off of the reactor building
Additional explosions caused meltdown of nuclear cores
Massive quantity of radioactive particles released into atmosphere

26. Chernobyl
Radioactive clouds drifted over Europe and even into the United States
Fires raged at the reactor for 9 days
45,000 inhabitants of Pripyat (3 miles from plant) not evacuated for 36 hours
X10 more fallout than the Hiroshima bomb
Radiation sickness...thyroid cancer...leukemia

30. Long-lasting effects on forest products (game…mushrooms…berries…)
Chernobyl
210,000 people evacuated from an area of 4300 km2.
Long-lasting effects on forest products (game…mushrooms…berries…)
Initial effects on flora/fauna populations:
- increased mortality
- decreased reproduction

31. The recovery of affected biota in the exclusion zone has been facilitated by the removal of human activities, e.g., termination of agricultural and industrial activities. As a result, populations of many plants and animals have eventually expanded, and the present environmental conditions have had a positive impact on the biota in the Exclusion Zone. Indeed, the Exclusion Zone has paradoxically become a unique sanctuary for biodiversity.