APES Ch. 5, part 2
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Transcript of APES Ch. 5, part 2
Biodiversity, Species Interactions, and Population
Control
Biodiversity, Species Interactions, and Population
Control
Ch. 5, part 2
Miller & Spoolman, 16th ed.
Ch. 5, part 2
Miller & Spoolman, 16th ed.
Big Idea #2Big Idea #2Populations cannot grow indefinitely
because resource are limited and there is competition for those resources
Populations cannot grow indefinitely because resource are limited and there is competition for those resources
Population DynamicsPopulation DynamicsThe study of how
Distribution Age structurePopulation SizePopulation Density
These things change in response to changes in the environment
The study of how Distribution Age structurePopulation SizePopulation Density
These things change in response to changes in the environment
Some species count more than othersSome species count more than othersChanges in the growth rate of
Invasive speciesKeystone speciesEcosystem engineers
Has a greater impact on the biodiversity of an area than other species
Changes in the growth rate of Invasive speciesKeystone speciesEcosystem engineers
Has a greater impact on the biodiversity of an area than other species
DistributionDistribution
Population DynamicsPopulation DynamicsFor example:
How disease affects a populationHow the introduction of a nonnative species affects a
populationHow the presence of chemicals like pesticides affect
populations
Studying these things helps us identify keystone species
For example: How disease affects a populationHow the introduction of a nonnative species affects a
populationHow the presence of chemicals like pesticides affect
populations
Studying these things helps us identify keystone species
Population DistributionPopulation Distribution3 basic patterns:
ClumpedUniformRandom
3 basic patterns:ClumpedUniformRandom
Clumped DistributionClumped DistributionMost common in both plants and
animals
Most common in both plants and animals
Why clump?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
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
UniformUniformEspecially in plantsSecrete chemicals that prevent others
from growing nearbyIncreases chances of getting the water and
soil nutrients it needs
Especially in plantsSecrete chemicals that prevent others
from growing nearbyIncreases chances of getting the water and
soil nutrients it needs
RandomRandomPretty rareOccurs when there is no good reason for
the other types
Pretty rareOccurs when there is no good reason for
the other types
Random, uniform, clumped? Why? Random, uniform, clumped? Why?
Population SizePopulation Size
Population SizePopulation Size4 variables
Birth rate (natality) +Death rate (mortality) -Immigration rate +Emigration rate -
Let’s try some math!
4 variablesBirth rate (natality) +Death rate (mortality) -Immigration rate +Emigration rate -
Let’s try some math!
Biotic PotentialBiotic PotentialA population’s capacity for growth
under ideal conditionsGeneral rule of thumb:
Big things have low biotic potentialLittle things have high biotic potential
A population’s capacity for growth under ideal conditions
General rule of thumb:Big things have low biotic potentialLittle 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
Intrinsic Rate of Increase (r)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 lifeHave short generationsCan reproduce oftenHave lots of offspring each time
The rate at which a population would grow if it had unlimited resource
Species with high “r” usually:Reproduce early in lifeHave short generationsCan reproduce oftenHave lots of offspring each time
So what’s the difference between biotic potential and intrinsic rate of increase?
Reproductive StrategiesReproductive Strategiesr-selected species
High biotic potentialLots of offspringLittle or no parental careUsually opportunist species
r-selected speciesHigh biotic potentialLots of offspringLittle or no parental careUsually opportunist species
Reproductive StrategiesReproductive StrategiesK-selected species
Low biotic potentialFew offspringLots of parental careUsually competitive species
K-selected speciesLow biotic potentialFew offspringLots of parental careUsually competitive species
22 mo. Gestation, 5 22 mo. Gestation, 5 years between birthsyears between births
9 mo. Gestation, 9 mo. Gestation, 8 years between 8 years between birthsbirths
Most fall somewhere in the middleMost fall somewhere in the middle
Species can’t keep growing and growing…Species can’t keep growing and growing…There are limiting factors that prevent
thisCompetition for resourcesPredatorsDisease
There are limiting factors that prevent thisCompetition for resourcesPredatorsDisease
How do you feel about what you are learning? How do you feel about what you are learning? A. Happy
B. Frustrated
C. Suspicious
D. Love-struck
E. Confused
F. Overwhelmed
G. Other? _________________
A. Happy
B. Frustrated
C. Suspicious
D. Love-struck
E. Confused
F. Overwhelmed
G. Other? _________________
Check all that apply
Population DensityPopulation Density
Population DensityPopulation DensityThe number of individuals in
a given volume
The number of individuals in a given volume
Density-Dependent ControlsDensity-Dependent Controls
• Competition for resources
• Predation
• Parasitism
• Disease
• Poisoning
• Human Harvesting
• Competition for resources
• Predation
• Parasitism
• Disease
• Poisoning
• Human Harvesting
Density-Independent ControlsDensity-Independent Controls
• Natural disasters
• Global warming
• Ozone depletion
• Natural disasters
• Global warming
• Ozone depletion
Environmental ResistanceEnvironmental ResistanceThe combination of all the factors that limit the
growth of a populationTogether these factors determine the carrying
capacity (K) of the populationThe 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 populationThe maximum number of a species that can survive in a
given area
Alphabet SoupAlphabet Soup
What are the letter symbols we’ve learned and what do they stand for?
What are the letter symbols we’ve learned and what do they stand for?
Genetics and Population Dynamics
Genetics and Population Dynamics
Genetic DiversityGenetic Diversity
Difference in genes among members of a population
A very important factor in the long term health and survival of a population
Difference in genes among members of a population
A very important factor in the long term health and survival of a population
The Founder EffectThe 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
Founder Effect - a small group of individuals becomes separated from the larger population.
They may have less genetic diversity than the larger population
The Bottleneck EffectThe Bottleneck EffectWhen only a small
group survives some change in the environment
Lack of variation means less adaptability
Humans sometimes create bottlenecks in other species
When only a small group survives some change in the environment
Lack of variation means less adaptability
Humans sometimes create bottlenecks in other species
Small populations may experience genetic driftSmall populations may experience genetic drift
Fluctuations in gene frequencies in a small population from one generation to the nextThe smaller the size of the population, the
more likely there is to be a major shift in allele frequencies
Fluctuations in gene frequencies in a small population from one generation to the nextThe smaller the size of the population, the
more likely there is to be a major shift in allele frequencies
ExampleExampleIf 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?
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?
InbreedingInbreeding
Individuals in a small population mate with each other
Increase the frequency of defective genes
Individuals in a small population mate with each other
Increase the frequency of defective genes
Minimum viable population Minimum viable population The minimum number of individuals
needed to maintain a species for the long term (so no inbreeding!)
The minimum number of individuals needed to maintain a species for the long term (so no inbreeding!)
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
Population Growth PatternsPopulation Growth Patterns
StableStableFluctuates a little above and below
carrying capacityFound in stable ecosystems like rain
forests
Fluctuates a little above and below carrying capacity
Found in stable ecosystems like rain forests
Irruptive Irruptive Population explodes,
then stabilized at a lower level; often tied to the seasons
Population explodes, then stabilized at a lower level; often tied to the seasons
CyclicCyclicBoom and bust; like lynx and hare -
every few years/generations
Boom and bust; like lynx and hare - every few years/generations
LE 52-18
1960
Year
Mo
ose
po
pu
lati
on
siz
e
2,500
Steady decline probably caused largely by wolf predation
2,000
1,500
1,000
500
01970 1980 1990 2000
Dramatic collapse caused by severe winter weather and food shortage, leading to starvation of more than 75% of the population
Irregular
Age StructureAge Structure
Age StructureAge Structure
Quick ThinkQuick ThinkWhat are the pros and cons of:Rapid population growth?No population growth?Declining population?
What are the pros and cons of:Rapid population growth?No population growth?Declining population?
EconomicSocialEnvironmental
Choose 1: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 onShave 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 onShave off your head hair and eyebrows for
the rest of the semester
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