 Warm-up: (10-21-15)
*Ferret Article/rubric out for stamp!
 1. Read the article and answer the questions in your warm-up. No complete sentences. Do not copy the
questions.
 _________________________________
 Copy hw.
 Chapter 5-6
 Population Ecology
 Goals for today:
 Contrast top down and bottom up population controls
 Identify the pros/cons of sexual and asexual reproduction
 Identify the 3 types of survivorship curves
 Be able to give examples of “r” and “K” strategists
 Top-down or bottom-up?
 Evidence seems to show both happening
 Top-down – predators hunt and kill prey keeping prey pop. stable
 Bottom-up – prey are the food source that determine predator pop.
 Can you think of a bottom up example?
 REPRODUCTIVE PATTERNS
 Asexual reproduction: reproduce without exchanging genetic material.
 Offspring are exact genetic copies (clones).
 Ex. Bacteria, some plants.
 “a” in front of a word means…
 What is a disadvantage to asexual reproduction?
 Sexual reproduction: reproduction with exchange of genetic material
 What are some advantages?
 Disadvantages?
 Disadvantages:
 males do not give birth (female needs to produce two offspring to replace parents)
 increase chance of genetic defects
 Courtship/mating rituals can be costly (energy)
 Major advantages:
 genetic diversity
 offspring protection
 Sexual Reproduction: Courtship
 Courtship rituals consume time/energy
 Inflict injury on males during competition
 What are some examples of characteristics/rituals that consume time/energy?
 Opportunists: reproduce rapidly when conditions are favorable, or a new niche opens up
 Ex. Pioneer species
 Examples???
 Survivorship curves
 Survivorship curves: show how likely an organism is to survive at different times in its life.
 3 types of curves.(type I, II, and III)
100
% surviving 10
1




Age
Type I survivorship curve (late loss)
Ex. Humans or elephants
Other examples?
Type II survivorship curve (constant loss)
% surviving 100
10
1
Age
Probability of dying doesn’t change throughout life, simple decline day to day.
Ex. Some birds
 Type III survivorship curve (early loss)
% surviving 100
10
1
Age
Probability of dying is high when young, but if it survives, it has a high probability of living to old age.
Ex. Sea turtles, insects, oak trees
 What are some differences between type 1 and 3?
 r and K strategists
 r strategist: species that produce many "cheap" offspring.
 Little/no parental care
 Small, short-lived adults
 Reach reproductive age rapidly
 Ex. Type III survivorship
 Pioneer species would be (r,K) strategists.
 K strategist: species that produce few "expensive" offspring.
 Ex. Type I and II survivorship (humans)
 Lengthy parental care
 High ability to compete
 Reproduce later in life
 Low ability to adapt to change compared to r strategists.
 Why?
 r or K strategist?
 Reach reproductive age rapidly
 Reproduces later in life
 Less adaptable to change
 High biotic potential
 Opportunists
 Small, short-lived
 Fewer offspring
 No/little parental care
 Does not usually live in a rapidly changing environment
 Pioneer species
 Reproductive Patterns
 r-selected: opportunists
 K-selected: competitors.
 Check for Understanding:
 1. Wolves controlling a deer population is an example of what type of population control?
 2. Describe an r-selected organism.
 3. Which is better at adapting to environmental changes, r or K strategists. Why?