1. Survivorship Bubble Lab
You graphed your population survivorship % over the weekend!
Now we are going to use a different type of graph paper to make ANOTHER graph, for a different type of analysis
Semi-log graph paper!!!

3. Factors That Affect Populations

4. Populations Size Density Distribution Age structure Birth rate
Death rate
Population growth rate
Reproductive strategy

5. Population Density Describes the number of individuals per unit area
Usually, larger organisms have lower population densities because they require more resources to survive

6. Population Density cont.
Higher densities make it easier for organisms to find mates but leads to competition
They may also be more vulnerable to predators and disease

7. Population Distribution
Describes the spatial distribution of organisms within an area
Random distribution— individuals located haphazardly in space in no particular pattern

8. Population distribution
Uniform distribution— individuals are evenly spaced

9. Population distribution
Clumped distribution— organisms arranged according to the availability of resources needed to survive
Most common in nature

10. Age structure
Describes the relative numbers of organisms of each age within a population
A population made up mostly of individuals past reproductive age will decline over time
A population with many individuals of reproductive age will increase over time

11. Ages 0-14
Ages 15-44
Ages
Rapid Growth
Guatemala
Nigeria
Saudi Arabia
Slow Growth
United States
Australia
Canada
Male
Female
Zero Growth
Spain
Austria
Greece
Negative Growth
Germany
Bulgaria
Sweden

12. Survivorship Curves
Survivorship curves show the likelihood of death

13. Survivorship Curves
Type I survivorship curves have a high death rate at older ages
Type II survivorship curves have equal rates of death at all ages
Type III survivorship curves have highest death rates at young ages

14. Population Growth
Populations grow when the birth rate is higher than the death rate

15. Exponential Growth
When a population increases by a fixed amount each year

16. Factors limit exponential growth
Every population is eventually constrained by limiting factors
These may include
Habitat size
Food
Mates
Other resources

17. Logistic growth
Rises sharply at first but then begins to level off as the effects of limiting factors become stronger

18. Reproductive Strategies

19. Types of Reproduction

20. Sexual reproduction involves two parents
involves sex cells that contain half of the genetic information (sperm and egg)
offspring receive genes from both parents

21. Asexual Reproduction involves only one parent
offspring are genetically identical to parent
ex) strawberries, bacteria, mushrooms

22. Disadvantages of sexual reproduction
Males do not give birth
Females need to have twice as many young as an asexual organism to maintain the same number of young in the next generation
Increased change of genetic errors and defects
Courtship or mating rituals consume time and energy, can transmit disease, and can inflict injury on males of some species if they compete

23. Advantages of sexual reproduction
Provides greater genetic diversity
Greater chance of reproducing and evolving if environmental conditions change
Males of some species can gather food for the female and young and protect them

24. Practice Question 
Over time, most populations exhibit an S- growth curve that levels off at a value K. This value is known as
(A) equilibrium growth rate
(B) exponential growth rate
(C) carrying capacity
(D) logistic growth rate
(E) minimum population density

25. R-selected vs. K-selected
R-selected species have a capacity for a high rate of population increase
Have many small offspring
Little to no parental care or protection
Overcome the massive loss of offspring by producing so many that a few will survive
Algae, bacteria, rodents, annual plants (dandelions), and most insects

26. R-selected vs. K-selected
R-selected species are opportunists/generalists
Reproduce and disperse rapidly when conditions are favorable or when a disturbance opens up a new habitat or niche for invasion
Adapted to unstable climate and environmental conditions

27. ** Practice Question **
Most r-selected species go through
(A) irregular or irruptive population changes
(B) irruptive or stable population changes
(C) stable or irregular population changes
(D) stable or cyclic population changes
(E) cyclic or irregular population changes

28. R-selected vs. K-selected
K-selected species have a lower population growth rate
Have fewer, larger offspring with long life spans
Later reproductive age
Offspring are born fairly large, mature slowly, and have high parental care
Most large mammals, birds of prey, large and long- lived plants

29. R-selected vs. K-selected
K-selected species do well in competitive conditions when their population size is near the carrying capacity of their environment
Specialists
Competitors
Adapted to stable climate and environmental conditions

30. Practice Question!!
Which of the following types of species would be least susceptible to the fragmentation of its habitat due to human influences?
(A) generalists
(B) specialists
(C) large predators
(D) K-Selected species

31. Practice Question ;) Opportunist species are most commonly
(A) introduced exotics
(B) competitors
(C) K-strategists
(D) r-strategists
(E) none of the above

32. Review time… A bottom-heavy age structure diagram is indicative of
(A) a population at carrying capacity
(B) slow growth
(C) rapid growth
(D) low mortality rate
(E) low natality rate

33. Bet you’re excited!
Age structure diagrams provide information about a country’s
I. growth rate
II. Generational composition
III. Accumulated retirement funds
I only
II only
III only
I and II only
I, II, and III

34. Last one! The best measure of a society’s quality of life is its
Gross national product
Educational standards
Life expectancy
Infant mortality rate
Fertility rates