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Take your Population Lab out for me to check
Take a seat, Get out your PENCIL!
Changes to Populations
Ecological CommunityGroups of interacting organisms
Pond Community (lilly pads, frogs, fish, snakes, elodea, etc)Forest Community (trees, shrubs, squirrels, birds, deer, etc)Coral Reef Community (coral, sponges, sharks, fish, algae,
etc)
HabitatArea where community of organisms live.Requires 4 components:
Food, water, cover, space
EcosystemInteractions of communities of organisms with each
other and their habitat.
What are some terms used in Ecology to study organisms?
Increase Population1) Birth2) Immigration (entering a population)
Decrease Population3) Death 4) Emigration (leaving a population)
See if you can create an equation using these 4 terms for Population Growth, Population Decrease, Population Stability
4 factors that effect the size of a population…
Populations Increase: When Immigration + Births > Death + Emigration
Population Remains Stable:When Immigration + Births = Death + Emigration:
Populations Decrease: When Immigration + Births < Death + Emigration
Is the population increasing or decreasing?
Anything that prevents the growth of a population
What would happen without limiting factors?
What are Limiting Factors?
What is Carrying Capacity (k)?
The maximum population a species can maintain in a certain area without damaging the ecosystem.
Population can stabilize at K…
What happens when a population goes above carrying capacity?
29 introduced in 1944
More than 6,000 by 1963
Down to 42 by 1966
Populations also can crash if #s go above K…
How overpopulation and decrease (k)
Season Fluxuations
Seasonal Fluctuations
What will happen with World Population?
Territorial Animals need a large amount of space.
Loss of Habitat causes the decline of many species.
Limiting Factor #1: Space
Who took my towel?
Loss of trees/wooden posts caused a huge declineBetween 1935-1985 numbers declined by 90%
Loss of Space/Habitat Example: Bluebirds
Q. What are the major needs of an organism’s habitat? Answer- Food, water, cover, and space.
Leads to death via dehydration, starvation
Some animals will emigrate
Organisms that rely on one type of food are severely affected
Limiting Factor #2: Food and Water
Food and Water Example: Snowshoe Hare and Lynx
Limiting Factor #3: Climate and Weather
Temperature changes can affect plants and animals
Floods and storms can cause death & destruction of habitat
Climate Changes Example:Mosquito Populations
Mosquitoes breed in standing water
Rainfall creates puddles of standing water
Temperature Changes: Coffee Habitat
Impact of Temperature
Rise on Robusta Coffee
in Uganda.
*Developing countries,
whose economies often
rely heavily on one or two
agricultural products, are
especially vulnerable to
climate change.
*This graphic shows that
With an increase of only
2 degrees Celsius, there
would be a dramatic
decrease in the amount
of land suitable for
growing Robusta coffee
in Uganda.
Protection from predatorsProtection from weather
Limiting Factor #4: Cover
What is Edge?
Positives and Negatives of Edge…
Some organisms prefer edge, because they need the cover and specific species of plants that grow there to feed on…
Other species have their habitats Fragmented by roads, fields, farms, etc.
Habitat Fragmentation
Cover Example: Ruffed GrouseRuffed Grouse- Requires
brushy forests for cover and food. Most of Pa’s forest were logged (cut down) 80 to 100 years ago.
They grew into brushy forest allowing grouse populations to increase.
Forests are now maturing reducing cover and food causing populations to decline.
Land development has also reduced populations
White-tailed Deer
An increase in the number of predators to an area will impact prey species.
Limiting Factor #5: Increase Predation
Predicted that in one year house cats kill 1 billion songbirds! WATCH THIS
Predation Example: House Cats!
Spread quickly through high density populationsCan devastate populations with low genetic diversity
Limiting Factor #6:Disease
Mosquito born disease
5,697 crows reported dead in NYS in 1999
Disease: West Nile Virus
Fungus that has killed over one million bats90-100% of some species of hibernating bats are in
danger of being killed.
White Nose Syndrome
Plants that cannot tolerate too much or too little light can be affected
Limiting Factor #7:Light
Light Example: Tree Growth and ShadeAspen Pine Poplar = intolerant,
will dominate young forestsBeech, Fir, Hemlock, Maple =
tolerant will dominate older forests
Close proximity to humans causes some species to emigrate
Other species thrive
Limiting Factor #8: Human Presence
Think of an example where an organism does not have enough limiting factors.
What is the organism, how does this affect the habitat around that organism?
Reflection
Limiting factors lead to competition among organisms for available resources
A loss in a limiting factor can contribute to a decline in populations
Increased due to exotic species
Competition
~Introduced species not native or endemic to the area in question. ~Can cause competition for resources.
Exotic Species
Changes in Population
Watch this… http://www.youtube.com/watch?v=b98JmQ0Cc3k&feature=related
What is the solution? Is there one? Use the debate form I give you with directions to come up with solutions…if there are any…if we need them.
What do you believe about world population?