Biodiversity, Species
Interactions, and Population
Control
Ch. 5, part 2
Miller & Spoolman, 16th ed.
Big Idea #2
Populations cannot grow indefinitely
because resource are limited and there is
competition for those resources
Population Dynamics
The study of how
 Distribution
Age structure
Population Size
Population Density
These things chan...
Some species count more than others
Changes in the growth rate of
Invasive species
Keystone species
Ecosystem engineer...
Distribution
Population Dynamics
For example:
How disease affects a population
How the introduction of a nonnative species affects a...
Population Distribution
3 basic patterns:
Clumped
Uniform
Random
Clumped Distribution
Most common in both plants and
animals
Why clump?
1. Cluster where there are resources
2. More likely to find resources if they
work together
3. Protection from ...
Uniform
Especially in plants
Secrete chemicals that prevent others
from growing nearby
Increases chances of getting the...
Random
Pretty rare
Occurs when there is no good reason for
the other types
Random, uniform,
clumped? Why?
Population Size
Population Size
4 variables
Birth rate (natality) +
Death rate (mortality) -
Immigration rate +
Emigration rate -
Le...
Biotic Potential
A population’s capacity for growth
under ideal conditions
General rule of thumb:
Big things have low b...
Intrinsic Rate of Increase (r)
The rate at which a population
would grow if it had unlimited
resource
Species with high ...
Reproductive Strategies
r-selected species
High biotic potential
Lots of offspring
Little or no parental care
Usually...
Reproductive Strategies
K-selected species
Low biotic potential
Few offspring
Lots of parental care
Usually competiti...
Most fall somewhere in the middle
Species can’t keep growing and
growing…
There are limiting factors that prevent
this
Competition for resources
Predator...
How do you feel about what you
are learning?
A. Happy
B. Frustrated
C. Suspicious
D. Love-struck
E. Confused
F. Overwhelme...
Population Density
Population Density
The number of individuals in
a given volume
Density-Dependent Controls
• Competition for resources
• Predation
• Parasitism
• Disease
• Poisoning
• Human Harvesting
Density-Independent Controls
• Natural disasters
• Global warming
• Ozone depletion
Environmental Resistance
The combination of all the factors that limit the
growth of a population
Together these factors...
Alphabet Soup
What are the letter symbols we’ve learned
and what do they stand for?
Genetics and Population
Dynamics
Genetic Diversity
Difference in genes among
members of a population
A very important factor in
the long term health and
...
The Founder Effect
Founder Effect - a small
group of individuals
becomes separated from
the larger population.
They may ...
The Bottleneck Effect
When only a small
group survives some
change in the
environment
Lack of variation
means less
adapt...
Small populations may experience
genetic drift
Fluctuations in gene frequencies in a
small population from one generation...
Example
If I flip a penny 100 times, how
many heads should I get?
If I flip a penny 10 times,
would it seem really weird...
Inbreeding
Individuals in a small population
mate with each other
Increase the frequency of defective
genes
Minimum viable population
The minimum number of individuals
needed to maintain a species for the
long term (so no inbreed...
How do you feel about your knowledge
of genetics and population dynamics at
this point?
How do you feel about your knowled...
Population Growth Patterns
Stable
Fluctuates a little above and below
carrying capacity
Found in stable ecosystems like rain
forests
Irruptive
Population explodes,
then stabilized at a
lower level; often tied
to the seasons
Cyclic
Boom and bust; like lynx and hare -
every few years/generations
LE 52-18
1960
Year
Moosepopulationsize
2,500
Steady decline probably
caused largely by wolf
predation
2,000
1,500
1,000
50...
Age Structure
Age Structure
Quick Think
What are the pros and cons of:
Rapid population growth?
No population growth?
Declining population?
Econom...
Choose 1:
Would you rather…
Sleep in a bed of rats.
Catch a porcupine thrown from a 2nd
story
window.
Be sprayed by a s...
Stump the class
• Work in teams of 2-3
• Each person write one multiple choice
or short answer question on your index
card...
APES Ch. 5, part 2
APES Ch. 5, part 2
APES Ch. 5, part 2
APES Ch. 5, part 2
APES Ch. 5, part 2
APES Ch. 5, part 2
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APES Ch. 5, part 2

  1. 1. Biodiversity, Species Interactions, and Population Control Ch. 5, part 2 Miller & Spoolman, 16th ed.
  2. 2. Big Idea #2 Populations cannot grow indefinitely because resource are limited and there is competition for those resources
  3. 3. Population Dynamics The study of how  Distribution Age structure Population Size Population Density These things change in response to changes in the environment
  4. 4. Some species count more than others Changes in the growth rate of Invasive species Keystone species Ecosystem engineers Has a greater impact on the biodiversity of an area than other species
  5. 5. Distribution
  6. 6. Population Dynamics For example: How disease affects a population How the introduction of a nonnative species affects a population How the presence of chemicals like pesticides affect populations Studying these things helps us identify keystone species
  7. 7. Population Distribution 3 basic patterns: Clumped Uniform Random
  8. 8. Clumped Distribution Most common in both plants and animals
  9. 9. Why clump? 1. Cluster where there are resources 2. More likely to find resources if they work together 3. Protection from predators 4. Teamwork to catch prey 5. Mating group and/or help raising young
  10. 10. Uniform Especially in plants Secrete chemicals that prevent others from growing nearby Increases chances of getting the water and soil nutrients it needs
  11. 11. Random Pretty rare Occurs when there is no good reason for the other types
  12. 12. Random, uniform, clumped? Why?
  13. 13. Population Size
  14. 14. Population Size 4 variables Birth rate (natality) + Death rate (mortality) - Immigration rate + Emigration rate - Let’s try some math!
  15. 15. Biotic Potential A population’s capacity for growth under ideal conditions General rule of thumb: Big things have low biotic potential Little things have high biotic potential Blue whale & calf ants E. O. Wilson studied ants mostly Give an example of an organism with low biotic potential and an organism with high biotic potential
  16. 16. Intrinsic Rate of Increase (r) The rate at which a population would grow if it had unlimited resource Species with high “r” usually: Reproduce early in life Have short generations Can reproduce often Have lots of offspring each time So what’s the difference between biotic potential and intrinsic rate of increase?
  17. 17. Reproductive Strategies r-selected species High biotic potential Lots of offspring Little or no parental care Usually opportunist species
  18. 18. Reproductive Strategies K-selected species Low biotic potential Few offspring Lots of parental care Usually competitive species 22 mo. Gestation, 522 mo. Gestation, 5 years between birthsyears between births 9 mo. Gestation,9 mo. Gestation, 8 years between8 years between birthsbirths
  19. 19. Most fall somewhere in the middle
  20. 20. Species can’t keep growing and growing… There are limiting factors that prevent this Competition for resources Predators Disease
  21. 21. How do you feel about what you are learning? A. Happy B. Frustrated C. Suspicious D. Love-struck E. Confused F. Overwhelmed G. Other? _________________ Check all that apply
  22. 22. Population Density
  23. 23. Population Density The number of individuals in a given volume
  24. 24. Density-Dependent Controls • Competition for resources • Predation • Parasitism • Disease • Poisoning • Human Harvesting
  25. 25. Density-Independent Controls • Natural disasters • Global warming • Ozone depletion
  26. 26. Environmental Resistance The combination of all the factors that limit the growth of a population Together these factors determine the carrying capacity (K) of the population The maximum number of a species that can survive in a given area The combination of all the factors that limit the growth of a population Together these factors determine the carrying capacity (K) of the population The maximum number of a species that can survive in a given area
  27. 27. Alphabet Soup What are the letter symbols we’ve learned and what do they stand for?
  28. 28. Genetics and Population Dynamics
  29. 29. Genetic Diversity Difference in genes among members of a population A very important factor in the long term health and survival of a population
  30. 30. The Founder Effect Founder Effect - a small group of individuals becomes separated from the larger population. They may have less genetic diversity than the larger population
  31. 31. The Bottleneck Effect When only a small group survives some change in the environment Lack of variation means less adaptability Humans sometimes create bottlenecks in other species
  32. 32. Small populations may experience genetic drift Fluctuations in gene frequencies in a small population from one generation to the next The smaller the size of the population, the more likely there is to be a major shift in allele frequencies
  33. 33. Example If I flip a penny 100 times, how many heads should I get? If I flip a penny 10 times, would it seem really weird that I got 7 heads and only 3 tails? Why not?
  34. 34. Inbreeding Individuals in a small population mate with each other Increase the frequency of defective genes
  35. 35. Minimum viable population The minimum number of individuals needed to maintain a species for the long term (so no inbreeding!)
  36. 36. How do you feel about your knowledge of genetics and population dynamics at this point? How do you feel about your knowledge of genetics and population dynamics at this point? 0 – not even with prompting can I explain this topic 1 – with some prompting I could explain some of it 2 - I get the basics 3 – I understand it beyond just basic info without help 4 – I can apply what I know to a test question 0 – not even with prompting can I explain this topic 1 – with some prompting I could explain some of it 2 - I get the basics 3 – I understand it beyond just basic info without help 4 – I can apply what I know to a test question
  37. 37. Population Growth Patterns
  38. 38. Stable Fluctuates a little above and below carrying capacity Found in stable ecosystems like rain forests
  39. 39. Irruptive Population explodes, then stabilized at a lower level; often tied to the seasons
  40. 40. Cyclic Boom and bust; like lynx and hare - every few years/generations
  41. 41. LE 52-18 1960 Year Moosepopulationsize 2,500 Steady decline probably caused largely by wolf predation 2,000 1,500 1,000 500 0 1970 1980 1990 2000 Dramatic collapse caused by severe winter weather and food shortage, leading to starvation of more than 75% of the population Irregular
  42. 42. Age Structure
  43. 43. Age Structure
  44. 44. Quick Think What are the pros and cons of: Rapid population growth? No population growth? Declining population? Economic Social Environmental
  45. 45. Choose 1: Would you rather… Sleep in a bed of rats. Catch a porcupine thrown from a 2nd story window. Be sprayed by a skunk. Let a rattle snake slither across your body. Let bumble bees cover you from head to feet. Let a tarantula walk across your face. Give a speech to the student body with only your underwear on Shave off your head hair and eyebrows for the rest of the semester Would you rather… Sleep in a bed of rats. Catch a porcupine thrown from a 2nd story window. Be sprayed by a skunk. Let a rattle snake slither across your body. Let bumble bees cover you from head to feet. Let a tarantula walk across your face. Give a speech to the student body with only your underwear on Shave off your head hair and eyebrows for the rest of the semester
  46. 46. Stump the class • Work in teams of 2-3 • Each person write one multiple choice or short answer question on your index cards from Ch. 4 or 5 • Question on one side, answer on the other • Share your questions with your team and revise if necessary • Give your cards to Beck to share with the class

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