Transcript Populations and Communities

11/28 Bell Work
Capt. Frank was out for a walk when it started to rain.
He did not have an umbrella and he wasn’t wearing a
hat. His clothes were soaked, yet not a hair on his
head got wet.
 How could this happen?
11/28 Schedule
 Presentations? 7 min for final prep.
 Notes Ch 5.1 “Populations”
 Ch 5 Dir Rdg – due TBA
All Meiosis unit assignments
MUST be in TODAY!
Assignments:
1. Dir Rdg Ch 5 “Pop” - TBA
Unit: Populations and
Communities
Ch 5
1. Describe and evaluate how living things interact.
2. Explain how genotype and phenotype variation
affects a species success.
Ch 5.1 “Populations”
Objectives:
 Explain why it’s important to study populations.
 Compare and contrast exponential and logistic growth.
 Describe factors that affect population size.
Exponential Introduction
You have just been hired for a one month job. You will be
paid one cent on the first day. Each day your pay doubles.
Estimate how much money you would earn on the tenth,
twentieth, and final day of July.
Actual answers….
10th day - $5.12
20th day - $5,242.88
31st day - $10,737,418.24
What Is a Population?
 A population is made up of a group of same species
in one place at one time that can interbreed.
 Populations can be small or large.
 Some stay at nearly the same number for years.
 Some die out from lack of resources.
 Others grow rapidly.
 Understanding population growth is important.
 Members of populations interact with each other and
other species.
Population Growth
Births, deaths, immigration, and emigration all effect
population growth.
Positive growth => add
 Births and Immigration
Negative growth => subtract
 Deaths and Emigration
Population Growth,
continued
Population vs. Time Models
 Exponential (“J” curve)
 Logistic (“S” curve)
“J curve”
“S Curve”
Population Growth,
continued
Exponential growth: when numbers increase by a certain
factor in each successive time period.
 Example: 2x, 3x + 1, etc
 Numbers grow slowly when population is small, but
speeds up as populations get larger.
 “Unlimited Resources”
 Ex: bacteria, viruses, etc
11/29 Bell Work
Jack Axe charges $5 to cut a wooden log into 2 pieces.
 How much would he charge to cut a log into 4
pieces? Explain.
11/29 Schedule
 Presentations?
 Finish notes Ch 5.1 “Populations”
 Real Beauty and the Beast
 Work Time
 Ch 5 Dir Rdg – due TBA
Assignments:
1. Dir Rdg Ch 5 “Pop” - TBA
Population Growth
 In the real world…food, predators, and disease limit
population growth. Eventually, population growth
slows and may stabilize.
 The largest population that an environment can support
at any given time is called the carrying capacity.
Population Growth
Logistic growth: starts with a small number of individuals
and reaches a maximum depending on the carrying
capacity of the habitat.
 When a population is small, the growth rate is fast
because there are plenty of resources.
 As the population approaches the carrying capacity,
resources become scarce.
Population Growth
Carrying Capacity Factors
 Density-dependent factors are affected by the number of
organisms present in a given area. (space, food, water…)
 Density independent factors affect a population regardless of
the population density. (weather, floods, fires...)
Population Growth
 Competition for food, shelter, and mates increases
between individuals of a population. As a result, the rate
of growth slows.
 The population eventually stops growing when the
death rate equals the birthrate.
Factors That Affect
Population Size
Factors causing populations to grow or shrink:

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


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Water (amount, quality, availability)
Weather and climate
Sunlight
Food
Predators
Human activities
Factors That Affect
Population Size
Biotic factors are density dependent. Food, predators, and
disease become big concerns.
Humans affect populations of many species.
 Down… disrupting habitats, introducing diseases, or
introducing nonnative species.
 Up… agriculture, conservation, pets
Human Population
Current world population is more than 7.8 billion people
and increasing.
 Reasons include…
 Better sanitation and hygiene
 disease control
 agricultural technology
 More resources will be needed to support them. As
demand increases, more pressure will be put on Earth’s
ecosystems.
Human Population
For most of human history, there were less than 10 million
people.
 Two thousand years ago, there were only 300 million
people.
 Human population began accelerating exponentially
starting in the late 1700s.
 Some scientists think that the population will grow to 9
billion in 50 years.
Human Population
Growth
The Real Beauty and the
Beast
Answer these questions in your notebook while you
watch the video.
1. Describe four social problems “Petrus Gonsalvus”
has because of his appearance.
2. Name the disorder and describe a possible cause.
3. Is this trait sex-linked? Dominant or recessive?
Explain.
4. Compare/contrast the experiences of “Petrus
Gonsalvus” with those of Larry Gomez.
11/30 Bell Work
You have two tanks that are exactly the same except
one tank has a 2 cm hole and the other has two 1 cm
holes.
 Which would drain more quickly, or does it make
no difference?
11/30 Schedule
 Finish and discuss “Real Beauty and the Beast”
 Work Time
 Ch 5 Dir Rdg – due TBA
 Missing notes
Assignments:
1. Dir Rdg Ch 5 “Pop” - TBA
12/1 Bell Work
 If you could have any superpower, what would it
be and why?
12/1 Schedule
 Turn in “Real Beauty and the Beast” video answers
 Notes Ch 5.2 “Interactions” online
 Interactions in Communities Worksheet
 Work Time
 Ch 5 Dir Rdg – due TBA
 Missing notes
Assignments:
1. Dir Rdg Ch 5 “Pop” – TBA
2. Interactions in Communities sheet -
Ch 5.2 “Interactions in
Communities”
Objectives
 Evaluate benefits and risks to species in different
kinds of relationships.
 Describe how symbiotic relationships affect the
species involved.
What’s your function?
Animals, like people, live in communities. Make a list of
different jobs that are done by people in your community
that keep the community running. Keep in mind that some
people may have more than one function in a community.
Symbiotic Interactions
Types of Symbiotic Relationships
 Predator-Prey: One organism kills and eats another.
 Parasitism: One organism lives in/on and eats a
host.
Examples
Rose spotted snapper and Cymothea exigua
Parasitism
Examples
Tinea pedis and Homo sapien peds 
Parasitism
Athlete’s foot
Symbiotic Interactions
Types of Symbiotic Relationships
 Mutualism: Both species benefit.
 Commensalism: One species benefits, other is
neither helped nor harmed.
Examples
Egyptian plover and crocodile
Mutualism
Examples
Manta ray and Remoras
Commensalism
Commensalism
Examples
Anemone and Clown fish
Commensalism
Examples
Epiphyte bromeliad and tree
Commensalism
Symbiotic Interactions
Symbiosis and Coevolution
 Species often develop adaptations in response to
one another.
 EX: Hosts immune systems try to keep parasites out
while parasites keep finding new or better ways to
infect.
Symbiotic Interactions
Symbiosis and Coevolution
 EX: Herbivores eat plants, but usually don’t kill
them.
 Plants defend themselves with thorns/spines or
with chemicals (bad taste, sick, fatal)
 Some herbivores have evolved ways to overcome
plant defenses.
Symbiosis Examples
 Classify the following relationships as predatorprey, parasite-host, mutualism, or commensalism.
 JUSTIFY your choice.
Symbiosis Examples
 Classify the following relationships as predatorprey, parasite-host, mutualism, or commensalism.
 JUSTIFY your choice.
Symbiosis Examples
 Classify the following relationships as predatorprey, parasite-host, mutualism, or commensalism.
 JUSTIFY your choice.
STOP NOTES
12/2 Bell Work
A group of soldiers was standing under the blistering
sun facing due west. Their sergeant shouted:
 Right turn!
 About turn!
 Left turn!
 Which direction are the soldiers now facing?
12/2 Schedule
 Turn in “Real Beauty and the Beast” - LATE
 Work Time
 Notes online
 Interactions in Communities Worksheet - TODAY
 Ch 5 Dir Rdg – due TBA
Assignments:
1. Dir Rdg Ch 5 “Pop” – TBA
2. Interactions in Communities sheet – TODAY
Looking for Barbie, Bratz,
etc doll donations for
science.
5 pts, can bring in 3.
ASAP!
12/5 Bell Work
How can it be that a man was once married to the
sister of his widow?
 Hint: What is a widow? Who did he marry first?
Widow’s walk
12/5 Schedule
 Notes Ch 5.3 “Shaping Communities”
 Fundamental vs Realied Niche
 Work Time
 Interactions in Communities Worksheet - LATE
 Ch 5 Dir Rdg – due WEDNESDAY
Assignments:
1. Interactions in Communities sheet – LATE
2. Dir Rdg Ch 5 “Pop” – WED
Looking for Barbie, Bratz,
etc doll donations for
science.
5 pts, can bring in 3.
ASAP!
Ch 5.3 “Shaping
Communities”
Objectives
 Explain how a species’ niche affects other organisms.
 Describe how competition affects species in
communities.
Carving a Niche
Habitat vs Niche
 Niche: The unique position occupied by a species
including physical use of its habitat and its role in
the community
 Habitat: Place where an organism lives.
 EX: What were Simba’s habitat and niche
in the Lion King?
Competing for Resources
Kinds of Niches
 The entire range of conditions where an organism or
species could survive is called its fundamental niche.
 The actual niche that a species occupies in a community
is its realized niche.
Competing for Resources,
continued
Competition Results
 One species wins, and the other loses. The loser is
eliminated from the habitat.
 Competitors survive in the same habitat because they
divide the resources.
Who gets to eat the zebra carcass?
Competing for Resources,
continued
Competitive Exclusion
 2 similar species with similar needs compete.
 One is slightly better at getting resources.
 The more successful species dominates the resources.
The less successful species either dies off or moves.
Galapagos finches evolved to
AVOID competitive exclusion.
Warbler Foraging Zones
Warblers divide tree when
hunting for insects.
Ecosystem Resiliency
Maintaining Ecosystems and Communities.
 Damaging factors: severe weather, humans, or
introduced species.
 Stability factors: Increased biodiversity and interactions
 A species can step into the opening if another dies.
Which is more
resilient…
rainforest or
tundra?
Ecosystem Resiliency,
continued
Effects of Predation
 Predation can reduce competition.
 They may reduce competition among other species.
 Predators are often a keystone species and determine
the health of the ecosystem.
Examples of
keystone
species.
12/6 Bell Work
If there are nine players on a baseball team, and three
strikes make an out and four balls make a walk, how
many outs are there in an inning?
12/6 Schedule
 Talk about test for this unit
 Work Time
 Research
 Ch 5 Dir Rdg – due WEDNESDAY
 Interactions in Communities Worksheet - LATE
Assignments:
1. Interactions in Communities sheet – LATE
2. Dir Rdg Ch 5 “Pop” – WED
Looking for Barbie, Bratz,
etc doll donations for
science.
5 pts, can bring in 3.
ASAP!
Test
 Includes project and paper test
 Symbiosis and Poisonous Plants
 2 days to research and prep for presentation
 PowerPoint or poster
 Present Friday
 ”Regular” paper test on Thursday
12/7 Bell Work
What common substance is more dense in its liquid
form than in its solid?
 HINT: What FLOATS when it freezes?
12/7 Schedule
 Work Time
 Research and work on Presentation
 Ch 5 Dir Rdg – due TODAY
 Interactions in Communities Worksheet - LATE
Looking for Barbie, Bratz,
etc donations for science.
5 pts, can bring in 3.
ASAP!
Assignments:
1. Interactions in Communities sheet – LATE
2. Dir Rdg Ch 5 “Pop” – TODAY
Ch 5 test Thursday, all
assignments in
Presentation Friday,
research sheet due
Bloodless Fish of Bouvet
Island
 Why is your blood red?
 Can you think of any animals that don’t have red
blood?
 Watch the video and answer the questions.