1. Make a connection between Easter and the movie “Night at the Museum” with chapter 8 (populations)

2. Do you know where it is?

3. Easter Island *Formed from volcanic eruptions *64 sq miles
*2300 miles west of Chile

4. Easter Island Story First inhabitants – 700 AD
people around 1500’s
1722, Europeans landed – 2500 people
What happened?

7. End of Easter Island – YouTube

8. APES Chapter 8

13. REINDEER ON ST. MATTHEW ISLAND

14. Key Concepts Environmental factors affecting populations
Role of predators in controlling populations
Reproductive patterns and species survival
Conservation biology
Human impacts on populations
Lessons about sustainable living

15. Oh Deer!

17. Sea Otters: Back from the Brink of Extinction?
Keystone species
Pollution effects
Importance of otters
Orcas
Fig. 8-1, p. 160

18. Populations
A. Characteristics of a population (1) size (number of indiv.) (2) density (spatial) (3) dispersion (spatial pattern) (4) age distribution

19. Population B. Measuring population size, density, distribution, etc.
APES Chapter 8
Population
B. Measuring population size, density, distribution, etc.
1. Count vs. Sampling
2. Sampling
Quadrats
Transects
Line
Belt
Mark-recapture
Quadrat - sample units or plots that vary in size, shape, number and arrangements, depending on the nature of the vegetation, site conditions and purpose of study.
Transects – line transect – presence or absence of species; continuous (every plant that touches the tape) or interrupted (every meter, every 10 meters, etc.)
belt transect – presence or absence, and abundance (% cover)  relative abundance

20. Quadrats - % Cover and #
Random
Along transect

22. Line Transect – Presence/Absence

23. Belt Transect Presence/Absence and Abundance
Number of individuals
Distance (m)

24. Mark-Recapture re ^

25. Chapter 8 Part 2

26. C. Dispersion Patterns of Organisms
APES Chapter 8
C. Dispersion Patterns of Organisms
Clumped or aggregated – common
Even – rare in nature, creosote bush is an example
Random
Fig. 8-2 p. 161

27. Creosote bush – even dispersion

28. Penguins – Even or Uniform Distribution

29. D. Population Dynamics
Changes in the characteristics of a population, occur in response to (1) environmental stress (2) changes in environmental
conditions

30. 1. Exponential Growth 2. Logistic Population Growth
APES Chapter 8
1. Exponential Growth 2. Logistic Population Growth
Right graph – logistic growth, S curve, levels off when meets carrying capacity (K)
Fig. 8-4, p. 163

31. ZPG = Zero population growth
APES Chapter 8
Population Dynamics
Carrying capacity - maximum population of a particular species that a given habitat can support over a given period of time.
Biotic potential (intrinsic rate of increase [r]) = births – deaths
 Population size =
births – deaths + immigration – emigration
ZPG = Zero population growth
Carrying capacity – maximum population of a particular species that a given habitat can support over a given period of time.
Pop growth rate also called intrinsic rate of natural increase (r) = births – deaths
High intrinsic growth rate – Show exponential growth, J curve
Environmental resistance – all factors that limit pop growth in nature
Population of a species at any given time is balance between intrinsic growth rate of species, and environmental resistance.
Right graph – logistic growth, S curve, levels off when meets carrying capacity (K)
Minimum viable population (MVP) – great importance to conservation biologists. Problems with small populations 1) not enough indiv to find mates, 2) genetically related indiv. May interbreed which weakens species, 3) low genetic diversity so not able to adapt in response to changing env. Conditions.
Result is extinction if Intrinsic growth rate is real low.

32. 5. Environmental resistance - all factors that limit pop growth in nature

33. APES Chapter 8
Population size influenced by birth rate, death rate, immigration and emigration
Population growth rate = births + immigration – deaths – emigration
Zero population growth (ZPG) – 0 net growth, increase = decrease
Biotic potential – capacity for growth, populations vary
Abiotic factors affecting population size – light (just right, too much or too little), temperature, chemicals
Biotic factors – reproductive rate, generalized/specialized niche, food supply, habitat, competitors, predators, disease, parasites, ability/inability to migrate to another habitat, ability/inability to adapt to env. change
Fig. 8-3, p. 162

34. Logistic vs Exponential Growth

35. Logistic Growth of Sheep Population
APES Chapter 8
Logistic Growth of Sheep Population
2.0
1.5
1.0 .5
Number of sheep (millions)
1800
1825
1850
1875
1900
1925
Year
Sheep on island of Tasmania between 1800 and Introduced, pop’s increased, reached carrying capacity, overshot it, stabilized and fluctuated around carrying capacity.
Logistic growth – growth can overshoot carrying capacity because of a reproductive time lag – the time needed for the birth rate to fall and the death rate to rise in response to resource overcomsumption.
Fig. 8-5, p. 163

36. When Population Size Exceeds Carrying Capacity
APES Chapter 8
When Population Size Exceeds Carrying Capacity
Overshoots
Reproductive time lag
Diebacks (crashes)
overshoots – a population grows rapidly and passes the carrying capacity
reproductive time lag – a lag between environmental change and change in length of gestation (or whatever changes); OR the time it takes for the birth rate to fall and the death rate to rise in response to resource over-consumption)
dieback (crash) - Sharp reduction in the population of a species when its numbers exceed the carrying capacity of its habitat. See carrying capacity.

37. Exponential Growth, Overshoot and Population Crash of Reindeer
APES Chapter 8
Exponential Growth, Overshoot and Population Crash of Reindeer
2,000
1,500
Number of reindeer
1910
1920
1930
1940
1950
Year
1,000
500
Dieback or crash – when overshoot K.
Reindeer were introduced to a small island off Alaska. Overshot the carrying capacity because there were no predators so they over-grazed the environment and ran out of food.
Human population of Ireland had similar crash during the potato famine due to the potato blight of About 1 million people died and 3 million emigrated to other countries.
Fig. 8-6, p. 164

38. 6. Minimum Viable Population
APES Chapter 8
6. Minimum Viable Population
(MVP) - the smallest possible size at which a biological population can exist without facing extinction
Start here 10/27/08 6th period

39. E. Reproductive Patterns and Survival
APES Chapter 8
E. Reproductive Patterns and Survival
1. Asexual reproduction – clones
Sexual reproduction – sex cells
Timing of reproduction
2. Semelparous - reproduce once and die; usually short-lived but salmon and agave
3. Iteroparous - reproduce many times; usually long-lived
Asexual reproduction – when mother cell divides to produce two identical daughter cells that are clones of the mother cell. Common in single-celled organisms like bacteria and yeast, and in some insects like aphids (parthenogenic females reproduce daughter clones), and in social insects like ants and honeybees
Sexual reproduction – reproduce offspring by combining sex cells or gametes from both parents, offspring have traits from both parents; increases genetic variation

40. Positions of r-selected and K-selected Species on Population Growth Curve
Number of individuals
Time
Carrying capacity
K species;
experience
K selection
r species;
r selection K
Fig. 8-9, p. 166

41. 4. r-Selected Species cockroach dandelion Many small offspring
APES Chapter 8
r-Selected Species
cockroach
dandelion
Many small offspring
Little or no parental care and protection of offspring
Early reproductive age
Most offspring die before reaching reproductive age
Small adults
Adapted to unstable climate and environmental
conditions
High population growth rate (r)
Population size fluctuates wildly above and below
carrying capacity (K)
Generalist niche
Low ability to compete
Early successional species
Opportunists 4.
r-selected species – exponential growth, High intrinsic rate of increase (r) reprod early in life, have short generation times, reproduce many times, have many usually small offspring, little or no parental care given to offspring, short-lived (usually have life-span of less than year). Reproduce often and many so it doesn’t matter if some offspring don’t survive. Tend to be opportunists – reproduce and spread rapidly in good conditions or when disturbance opens space, early successional species. Don’t last because they can’t survive changing env. conditions, or invasion by more competitive species – irregular and unstable boom-bust cycles.
Fig. 8-10a, p. 167

42. 5. K-Selected Species elephant saguaro Figure 8-10b, p. 167
APES Chapter 8
K-Selected Species 5.
elephant
saguaro
Fewer, larger offspring
High parental care and protection of offspring
Later reproductive age
Most offspring survive to reproductive age
Larger adults
Adapted to stable climate and environmental
conditions
Lower population growth rate (r)
Population size fairly stable and usually close
to carrying capacity (K)
Specialist niche
High ability to compete
Late successional species
Competitor species
K-selected species – K for carrying capacity, AKA competitor species, put little energy into reproduction, reproduce later in life, few offspring, long generation times, put most of energy into nurturing and protecting young until they reach reproductive age. Young develop inside mother, are large, mature slowly. Results in a few big and strong individuals that can compete for resources. Do well in competitive situations. Show logistic growth. e.g., most large mammals (elephants, whales, humans), birds of prey, large and long-lived plants like trees. Many are prone to extinction because of long generation times and low reproductive rates.
Do best in ecosystems with fairly constant environmental conditions, compared to opportunist species that thrive in habitats with disturbances.
Most speices are somewhere in between r-selected and K-selected strategies
Figure 8-10b, p. 167

43. 6. Survivorship Curves Age
APES Chapter 8
6. Survivorship Curves
late loss or Type I (usually K–strategists), in which high mortality is late in life
constant loss or Type II (such as songbirds), in which mortality is about the same for any age;
early loss or Type III (usually r–strategists), in which high mortality is early in life.
Late loss – high survival in young, high mortality in oldest age group only
Constant loss – - death rate same no matter the age
Early loss - high mortality among young
Age
Fig.8-11, p. 167

44. F. Limitations on Population Size
APES Chapter 8
F. Limitations on Population Size
Carrying capacity
Density-dependent controls – greater effect on population as density increases. e.g. competition, predation, disease, parasitism
Density-independent controls – affect population’s size regardless of density e.g. flood, hurricane, drought, fire, pesticide, habitat destruction
Carrying capacity - maximum population of a particular species that a given habitat can support over a given period of time.
Density-independent controls – affect population’s size regardless of density. Examples are floods, hurricanes, severe drought, fire, habitat destruction and pesticides.
Density-dependent controls – greater effect on population as density increases - competition for resources, predation, parasitism, disease. Bubonic plague, 14th century Europe, at least 25 million people died.

47. 4. The Role of Predation in Controlling Population Size
APES Chapter 8
4. The Role of Predation in Controlling Population Size
a. Predator-prey cycles b.Top-down control
c. Bottom-up control
Population size (thousands)
160
140
120
100 80 60 40 20
1845
1855
1865
1875
1885
1895
1905
1915
1925
1935
Year
Hare
Lynx
Predator-prey cycles– poorly understood; sharp increase in numbers followed by periodic crashes.
– Lynx-hare cycle – 10 year cycle. Once thought that thy regulated each other’s cycles. Now think that hare population is regulated by (1) predation by lynx and other predators (top-down control), and (2) changes in available food supply (bottom-up control). Lynx population fluctuates in response to hare population.
Moose and wolf on Isle Royale, between Minnesota and Ontario – moose immigrated there across ice in early 1900’s. By 1928 they had stripped island of their preferred food. In 1940’s timber wolves immigrated across ice to island. The multiplied and killed old, sick and young moose, keeping their numbers from reaching high levels again. Starting in 1980 the wolf population has declined due to disease and low reproductive rate due to lack of genetic variability from inbreeding. Moose population rose and crashed. Then wolf population rose by eating dying mooses, so the populations’ cycling continues.
Fig. 8-8, p. 165

48. Rabbits and Wolves Simulation
Get into groups of 2 people
Log into a computer
Go the simulation website
Answer questions on worksheet

49. G. Natural Population Curves
APES Chapter 8
G. Natural Population Curves
/chaotic
4 types of population fluctuations
Stable – slight fluctuations above and below carrying capacity. Undisturbed tropical rain forests – little variation in temperature or precipitation
Irruptive – occasionally explodes or irrupts to a higher peak, some factor temporarily increases carrying capacity – more food or fewer predators. House mouse, raccoon.
Cyclic – occur over regular time period for poorly understood reasons. e.g. (1) lemmings – rise and fall every 3-4 years, (2) grouse, lynx, and snowshoe hare – rise and fall on 10 year cycle.
Irregular/chaotic – chaotic behavior, no recurring pattern. Either due to chaos in system, or unknown underlying patterns and interactions.
Fig. 8-7 p. 164

50. Conservation Biology: Sustaining Wildlife Populations
What is conservation biology?
Which species are endangered?
How are ecosystems functioning?
How can ecosystems be sustained?
Principles of conservation biology
Aldo Leopold’s ethical principles
Bioinformatics

51. H. Conservation Biology
Conservation biology is the interdisciplinary science that deals with problems of maintaining Earth's biodiversity, including genetic, species, and ecosystem components of life.
conservation involves the sensible use of natural resources by humans;
three underlying principles:
biodiversity and ecological integrity are useful and necessary for life and should not be reduced by human activity;
humans should not cause or hasten premature extinction of populations and species;
the best way to preserve biodiversity and ecological integrity is to protect intact intact ecosystems and sufficient habitat.
© Brooks/Cole Publishing Company / ITP

52. Conservation Biology
1. Habitat fragmentation is the process by which human activity breaks natural ecosystems into smaller and smaller pieces of land called habitat fragments.
one concern is whether remaining habitat is of sufficient size and quality to maintain viable populations of wild species;
large predators, such as grizzly bears, and migratory species, such as bison, require large expanses of continuous habitat;
habitat fragments are often compared to islands, and principles of island biogeography are often applied in habitat conservation.
© Brooks/Cole Publishing Company / ITP

53. I. Human Impacts on Ecosystems
Habitat degradation and fragmentation
Simplifying natural systems (monocultures)
Wasting Earth’s primary productivity
Genetic resistance
Eliminating predators
Introducing non-native species
Overharvesting renewable resources
Interfering with cycling and flows in ecosystems

54. Human Impacts on Ecosystems
Some principles for more sustainable lifestyles:
we are part of, not apart from, Earth's dynamic web of life;
our lives, lifestyles, and economies are dependent on the sun and earth;
we never do merely one thing;
everything is connected to everything else; were are all in it together.
According to environmentalist David Brower we need to focus on "global CPR –– that's conservation, preservation, and restoration".
© Brooks/Cole Publishing Company / ITP

55. Human Footprint on Earth’s Land Surface
Fig. 8-12, p. 169

56. I. Four Principles of Sustainability
Solar
Energy
Population
Control
PRINCIPLES OF
SUSTAINABILITY
Nutrient
Recycling
Biodiversity
Fig. 8-13, p. 170

57. Learning Sustainability from Nature
Dependence on nature
Interdependence
Unpredictability (see Connections on p. 170)
Limited resources
Recycle wastes

58. Principles of Sustainability
Runs on renewable
solar energy.
Recycles nutrients
and wastes.
There is little waste
in nature.
Uses biodiversity
to maintain itself
and adapt to new
environmental
conditions.
Controls a species'
population size
and resource use
by interactions
with its environment
and other species.
Principles of Sustainability
How Nature Works
Lessons for Us
Rely mostly on
renewable solar
energy.
Prevent and reduce
pollution and recycle
and reuse resources.
Preserve biodiversity
by protecting
ecosystem
services and
preventing
premature extinction
of species.
Reduce births and
wasteful resource
use to prevent
overload and
depletion and
degradation of
resources.
Solutions:
Implications
of the Principles
of Sustainability
Fig. 8-14, p. 171

59. J. Ecosystem Restoration
Can we restore damaged ecosystems?
yes, in some cases; but prevention is easier;
natural restoration is slow relative to human life spans;
active restoration can repair and protect ecosystems, but generally with considerable effort and expense;
example: in Sacramento, California, rancher Jim Callender restored a wetland by reshaping land and handplanting native plants; man of the native plants and animals are now thriving there;
restoration requires solid understanding of ecology;
it is not possible to undo all ecological harm, e.g., we can't foster recovery of an extinct species.
© Brooks/Cole Publishing Company / ITP

60. Mark-Recapture Lab re ^
Example:

61. Initial
Day 1
Day 2
Day 3
Day 4
Day 5
Control 1 2 3 4 5
C Avg
Exp 1
Exp Avg