Chapter 5 POPULATIONS CPI Biology Holliston HS

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Chapter 5POPULATIONSCPI BiologyHolliston HS
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5-1 How Populations Grow

• 3 Important Characteristics of a Population
• __________________________________ the area
  (range) inhabited by a population
• ______________________________________
  individuals per unit area (ex) tall saguaro
  cactus
• ___________________

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Population Growth

• Three Factors Affect Population Size
• _________________
• _________________
• individuals that ___________________________
• __________________ movement of individuals INTO
  an area
• __________________ movement of individuals OUT
  OF an area

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• If birthrate gt deathrate, then pop. _________
• If deathrate gt birthrate, then pop. _________
• If birthrate deathrate, then pop. _________

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Exponential Growth

• What if a populations has a lot of space and
  food with no threat of predators or disease?
• ____________________
• occurs when individuals in a population reproduce
  at a constant rate
• growth under ideal conditions with unlimited
  resources
• _________________ CURVE Initial slow growth ?
  over time becomes larger infinitely

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J-SHAPED CURVE
then grows exponentially
Starts off slow
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Logistic Growth

• Exponential growth happens initially but does not
  continuewhat slows down population growth?
• resources become less available
• birthrate decreases or deathrate increases
• immigration decreases or emigration increases
• This is called ___________________
• when a populations growth slows or stops
  following a period of exponential growth
• ________________________ CURVE

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LOGISTIC GROWTH population growth levels off
growth rate __
_______________________
Largest number of individuals environment can
support
S-SHAPED CURVE
Number of Organisms
Time (hours)
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5-2 LIMITS TO GROWTH

• _______________________FACTORS factors that
  cause population growth to decrease 2 types
• DENSITY-______________________ limiting factors
  that depend on population size limits growth
  when the population reaches a certain level (do
  not affect small, scattered populations)
• Competition Predation
• Parasitism Disease
• DENSITY-_____________________ limiting factors
  that affect all populations regardless of size
• Unusual Weather Natural Disasters
• Human Disturbances (ex) cutting forests

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• 1) ___________________________ organisms in
  larger populations compete for food, water,
  space, sunlight, other essentials (ex) puffins
  compete for nesting sites

DENSITY-DEPENDENT FACTORS
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• 2) ________________________ (ex) periodic
  increases in the moose population (prey) quickly
  followed by increase in wolf population ? cycle
  repeats

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• 3) _________________________________
• (ex) larval sphinx moth attacked by parasitic
  moth? wasp inserts eggs under skin ? wasp larvae
  feeds on host internally ? appears as white
  cocoons

DENSITY-DEPENDENT FACTORS
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Density-Independent Factors

• Population size doesnt matter
• Unusual weather, natural disasters, seasonal
  cycles, human activities

(ex) Drought
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6-3 BIODIVERSITY biological diversity

• Variety is the spice of life!

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The Value of Biodiversity

• ________________ the sum total of all
  genetically based variety of organisms in the
  biosphere one of Earths greatest natural
  resources
• _______________
• Industrial products
• _______________ (painkillers, antibiotics, heart
  drugs, antidepresseants, anticancer drugs)

(ex) Rosy periwinkle used to treat cancers
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Different Types of Biodiversity

• ________________ DIVERSITY the variety of
  habitats, communities, and ecological processes
  in the living world
• ________________ DIVERSITY of different
  species in the biosphere (1.5 million)
• ________________ DIVERSITY different forms of
  genetic info carried by all organisms

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Threats to Biodiversity

• HUMAN ACTIVITIES alters habitats ? reduces
  biodiversity ? may lead to endangerment or
  extinctionexamples
• Developing land ? splits ecosystemsthis is
  called ________________________
• Hunting
• Introducing toxic substances
• Introducing new species

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• 1) HABITAT FRAGMENTATION developments split
  ecosystems ? results in smaller biological
  _____________ ? more vulnerable to disturbances

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2) __________ DEMAND FOR WILDLIFE PRODUCTS animal
species hunted for food or other products (meat,
fur, hides)

• Carolina parakeet ? feathers for decorating hats
  (1800s) ? now extinct

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3) ______________ Introducing Toxic Substances
(EX) DDT

• POLLUTION serious problems arise when toxic
  compounds accumulate in organisms tissues
• HISTORY OF DDT widely used pesticide for
  controlling agricultural pests was seemingly
  harmless but was hazardous because it was
• _________________________________ cannot be
  broken down by organisms
• NOT ELIMINATED FROM BODY builds up in organisms
  tissues ? can become concentrated to higher
  levels
• ____________________________________
  concentrations of a harmful substance increase at
  higher trophic levels in a food chain

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Fish-Eating Birds
10,000,000
BIOLOGICAL MAGNIFICATION
Large Fish
1,000,000
Small Fish
100,000
Magnification of DDT concentration represented by
orange dots ? multiplied as it passes up food
chain from producers to consumers.
10,000
Zooplankton
1000
Producers
1
Water
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What happened with DDT?

• POPULATIONS THREATENED fish-eating birds like
  osprey, brown pelican, and eagles (eggs made
  fragile from DDT)
• _________________ book written in 1962 by Rachel
  Carsen that alerted people to the dangers of DDT

• _________________! DDT no longer used in the
  early 1970s ? recovery in bird populations

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4) Introduced Species

• INTRODUCING NEW SPECIES apparently harmless
  organisms accidently or intentionally brought
  into new habitats ? often become
• _____________________________ reproduce rapidly
  because new habitat lacks parasites predators
  to control their population
• (ex) __________________ - aquatic pest came to US
  in 1980s ? reproduced so fast ? drove other
  species to near extinction
• (ex) __________________ furry rodents eating
  water plants that protect fragile US shorelines
  from erosion

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INVASIVE SPECIES
NUTRIAS
ZEBRA MUSSELS
LEAFY SPURGE European weed displacing native
plants
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Conserving Biodiversity

• _______________________ wise management of
  natural resources including preservation of
  habitats wildlife protects biodiversity
• STRATEGIES FOR CONSERVATION
• Captive breeding programs young animals raised
  in a protected surroundings until the population
  is stable ? later returned to wild
• Protecting entire ecosystems set land aside,
  expand existing parks, reserves, forests
  designate marine sanctuaries
• Identify __________________________ locate
  problem areas where specific s of habitats
  species are in immediate danger of extinction as
  a result of human activity

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SUCCESS IN CONSERVATION!

• 1872, ______________________ PARK worlds first
  national park
• 1896, 1ST CONSERVATION MOVEMENT to prevent
  extinction of birds in Boston, refusal to buy or
  wear plumed hats
• 1900, ______________________ ACT 1st major
  conservation law that bans transporting illegally
  killed animals across stated lines
• 1966, ______________________ ACT identifies,
  researches protects endangered species
• 1970, __________________________ 1ST celebration
  in NY to rally against pollution population
  overgrowth