Population Ecology

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Population Ecology

• Population Dynamics
• Chapter 4

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Population Characteristics

• Population- group of organisms of the same
  species in the same area
• Population characteristics include
• Density, spatial distribution and growth rate
• Population Density- number of organisms in an
  area
• 38 deer/square mile in NJ

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Dispersion PatternsUniform (solitary)

• Groups are evenly spaced
• Members often dont want to be near each other

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Dispersion PatternsClumped (herds)

• Members are usually social
• Members are usually around important resources

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Dispersion PatternsRandom (groups)

• Not centered around a certain resource
• Some members are social, some are not

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Limiting Factors

• Keep populations from growing indefinitely
• Without these, populations would infinitely large
• Can be abiotic
• Hiding places
• Temperature
• Rainfall
• Can be biotic
• Food
• Predators
• Disease

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Density Independent Limiting Factors

• Does not depend on the number of organisms in an
  area
• Usually abiotic
• Weather (floods, temperatures, hurricanes)

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Density Dependent Limiting Factor

• Depends on Density
• Often Biotic
• Parasites, Predators, Disease, Competition

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Population Growth

• Population growth rate- measure of how fast a
  population grows
• Birth and Immigration increase Populations
• Death and Emigration decrease populations

r (b d) (i e)
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Exponential Growth

• Growth without limiting factors
• J shaped Curve
• Exponential growth
• Many young survive
• Cannot occur forever!
• Why?

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Logistic Growth

• Population Strains Resources
• Growth will slow or stop
• Fluctuates around a carrying capacity (K)
• S- Shaped

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Carrying Capacity

• Carrying Capacity- the maximum number of
  individuals that the environment can support for
  the long term
• Limited by nutrients, oxygen, and water

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Reproductive Strategiesr-selected

• Many young
• Reproduce quickly
• Little parental care
• Small in size
• Examples
• Insects
• Plants (esp weeds)
• Frogs

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Reproductive Strategiesk-selected

• Large organism
• Much parental care
• Mature Late
• Few Young
• Examples
• Kangaroo and Koala
• Humans
• Redwood trees
• Whales

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Human Populations

• Humans change their environment to increase
  carrying capacities
• Technologies reduce death rates
• Medicine
• 70 million new people every year
• 53 years to double the population
• Growth rate is slowing
• AIDS
• Voluntary Population Control
• Ie. China One Child Policy

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Trends

• Developed countries have a lower birth rate and
  later date rate
• USA (2009)- 13.9/1000 death _at_ 78.11 years
  old
• USA (1850) 50/1000 death _at_ 38.3 years old
• Why?
• Zero population growth, so
• Birthrate Immigration rate Death rate
  emigration rate

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Age Structure Diagrams
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More Age Structure Diagrams
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9 Week Test

• Lets take a minute to talk

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Grading Policy

• All marking periods and final exam is worth 20
  according to new school policy
• No midterms
• So finals count more!

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What are we doing?

• 9 week, 18 week 27 week, and 36 week exams
• Will help prepare you for the EOC Bio Test
• Grade goes on the individual marking period.

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What to know for 9 week

• Food chain and food web
• producer/autotroph, consumers (herbivores,
  carnivores, omnivores)
• Arrow indicates flow of energy
• Trophic levels
• Pyramid of energy and biomass 10 rule
• Symbiotic relationships
• Mutualism, commensalism, parasitism
• Biodiversity and biomes
• Tropical rainforest have most biodiversity
• Read and interpret graph

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More topics

• Photosynthesis who does it, what is it?
• Uses CO2 and water to make glucose and release
  oxygen
• Respiration opposite of photosynthesis
• Uses oxygen to break down glucose, release water
  and CO2
• Indicator species ex. Amphibians
• What will happen to insects if lose frogs? What
  about snakes?
• Cycles water, carbon, phosphorus, nitrogen, and
  greenhouse
• Population studies-
• S and J curves
• Microscope

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Biodiversity and Conservation
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Biodiversity

• Biodiversity-variety of life
• Extinction- no more member of a species exists
• Genetic diversity- variety of genes in a
  population
• Higher diversity offers a better chance to
  survive a disaster
• Some individuals are naturally resistant to some
  disease
• Humans and AIDS (delta 32 mutation)

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Species Diversity

• Species Diversity- number of different species
  and the abundance in an area
• What biomes have a higher diversity?

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Why preserve Biodiversity?

• We may not know the benefit of an organisms yet
• Aspirins-from willow
• Penicillin comes from mold
• What's next?
• Healthy diversity
• Leads to healthy watersheds
• Clean drinking water
• Its beautiful

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Conservation

• Extinction Rates
• Background extinction- gradual process of a
  species going extinct
• Always present
• Caused by natural processes, climate change,
  natural disasters
• Mass extinction- large percentage of all living
  species become extinct in a short time
• Dinosaurs 65 million years ago

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Extinctions

• 73 of extinct mammals over the last 500 years
  are island species
• Why?
• Many of Hawaii's birds are extinct
• Ground nesters ie saffron finches
• Amphibians are currently in danger
• Why?

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Threats

• Humans- change natural conditions faster than
  organisms can adapt
• Humans- Overexploitation
• 50 million bison dwindled to 1000 in 1889
• Overexploitation may lead to extinction
• Passenger pigeon (next slide)
• Humans-habitat loss
• Not enough food
• Changed weather patterns

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Passenger Pigeon

• About 5 billion in N. American in 1600s-1700s
• Up to 90 nests /tree ? collapsed branches
• Migrating flocks shadowed sky 9am-4pm
• If shoot gun randomly birds would fall from
  sky
• Good food
• Females lay one egg a year
• Population decline lost habitat and hunted
• Stool pigeon name came from passenger pigeon
• Community bird like to be in groups
• Capture pigeon, tie to stool, stitch eyes shut so
  cry, move pigeon around while shrieking to
  attract other pigeons
• Last one died in zoo - 1914

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Bison Slaughter

• Bison hunted for sport
• Skulls used as fertilizer
• Purpose of Bronx Zoo was to replace the bison
  herds
• Now people grow bison for meat

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Habitat Disruption

• Changing on thing can have a big effect
• Whales disappear then plankton bloom
• ADD Dodo bird
• Habitat Fragmentation- separating an ecosystem
  into small areas
• Edge effect- temperature, humidity and species
  are different at edges than interiors
• Overlap makes the area unique

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Biomagnification

• Pollutants build up to high levels in carnivores
• The pollutants are fat soluble
• They enter the food chain at low levels
• Examples
• DDT- kills mosquitoes and other insects
  accumulates in birds (ie eagles) affects egg
  shells
• Mercury- accumulates in humans causing problems
  with the nervous system (vision, hearing and
  speech)
• Dioxin- causes organ disease, increased risk of
  cancer and a suppressed immune system

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Add Dioxins released when plastics are burned
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Acid Precipitation

• Caused by burning fossil fuels
• Sulfuric acid and nitric acid are formed
• Acid rain falls back as rain, snow fog or sleet
• Acid rain removes nutrients from soil and kills
  fish and other organisms

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Invasive Species

• Introduced or invasive species have been moved to
  their habitat
• Organisms are not kept in balance by natural means

• Examples
• Cane Toads
• Fire Ants
• Phragmities (the plant in the Meadowlands)
• Kudzu coming up!

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Kudzu Arrives

• Came to US in 1876 at Japan exhibit of the
  Centennial
• In 1930s used to halt soil erosion
• Promoted as miracle vine until 1953
• Is a legume adds N to soil
• Flowers are pretty

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Kudzu Today

• Not under control but learn to live with
• Vines used for baskets
• Free material!
• Expensive basket
• Bread and jelly
• Provides digestive nutrients
• Crohns disease difficult digesting food
• Kudzu soup made from solid people who have
  Crohns swear by ti

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Kud-Zoo
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Zebra Mussels

• First noticed in Great lakes in 1988
• Can live for days and weeks out of water
• If temperature and humidity is high
• 1 adult female produces between 30,000-400,000
  eggs per year
• Filter feeders
• Increase light penetration
• Increase algae growth

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• Between ¼ and ½ in long
• Razor sharp shells cut 1 in into human flesh
• so fine no realize cuts
• Cover may things
• Cost of damage is in billions of dollars

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The spread
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Wild Hogs

• From Europe
• Hernando DeSoto brought wild boars to FL for food
  and hunting
• Bred with feral and domestic hogs
• Today- wild hogs are damaging land in 39 states
• Damage 1.5 billion/year

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Bad piggies

• Opportunistic omnivores
• Will eat anything
• Wipe out native plant species
• Destroy crops, dig up seeded fields
• Erode soil, muddy stream
• Eat deer, livestock and bird and turtle eggs
• Hard to catch run 30 mph and can detect odors 7
  miles away or 25 ft underground

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Range has spread

• As far north as south NJ

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Conservation

• Industrialized countries use more resources
• Renewable resource- replaced by natural processes
• Nonrenewable- finite amount of the resource
  available
• Which are renewable and which are not
• Fossil Fuels Water
• Timber Kenaf
• Solar Radiation Hydropower
• Metals

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Sustainable Use

• Resources must be used at a rate they can be
  replaced
• All resources need to be used in an sustainable
  manner
• Nonrenewable resources
• Fossil Fuels
• Metals
• Renewable resources
• Timber
• Seafood

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Hot Spots

• 15 of the Earth Surfaces is considered a Hot
  Spot
• There are many endemic species
• They only exist at that location
• 70 of this habitat is lost

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Should we restore ecosystem?

• What ecosystems should be restored?
• How should we do it?
• Bioremediation-remove toxins by using living
  organisms
• Bioaugmentation- adding natural predators