Ecology

1
Ecology

• Communities and Biomes

2
Limiting Factors

• environmental factors that affect an organisms
  ability to survive
• Two types
• Density-dependent
• Density-independent

3
Limiting Factors

• Density-dependent factors
• has increasing effect as the population increases
  
• Examples

Shelter Space
Food Water supply
Predators
Disease
Parasitism
4
Predator-Prey Relationships
5
Limiting Factors

• Density-independent factors- affects all
  populations regardless of density
• Most abiotic factors

storm
flood
earthquake
temperature
fire
6

• What would a football field look like in thirty
  years if it was not cared for or played on?

?
7
Succession

• orderly, natural changes and species replacements
  that take place in the communities of an
  ecosystem

Lake Succession
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Succession

• Begins with
• Pioneer plants- first organisms to inhabit an
  area
• Ex. Moss and lichen

• Ends with
• Climax community- tends to remain stable or long
  periods of time with little or no change

9
Primary Succession

• colonization of a new site from rock

10
Secondary Succession

• sequences of changes that take place after a
  community is disrupted by natural or human
  actions.
• Ex.- abandoned building, fire, hurricane

11
Trends in Succession

• Small plants with short life cycles are
  replaced with large plants with long life
  cycles
• diversity increases
• less energy is wasted
• food webs become more complex
• populations stabilize

12
Biomes of the World

• Biome- a large group of ecosystems that share the
  same type of climax community
• Aquatic biomes- approximately 75 of the earths
  surface
• Oceans, lakes, rivers
• Terrestrial biomes- land

13
Terrestrial Biomes
14
Terrestrial Biomes
Sample Climatograph

• 3 factors that influence type of biome
• Latitude
• Altitude
• precipitation

Influences temperature
15
Terrestrial Biomes

• Tundra
• Taiga
• Temperate forest
• Tropical Rainforest
• Grasslands
• Desert

16
Tundra

• 12 cm precipitation per year
  usually
  snow
• long winters and darkness
• Permafrost -soil remains
  permanently frozen
• Long winters and darkness,
  Short summers
• Russia, Iceland, Greenland
• Low temperatures
• Plants have fast life cycles
• Animals-Snowshoe hare, caribou,
  reindeer, voles, ducks,
  geese

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Taiga

• largest biome
• wet climate, foggy acidic soil
• Most of Canada, Alaska, Eurasia
• 35 to 40 cm precipitation yearly
• Plants- large coniferous forest
  (firs, pines)
• Animals- Moose, elk, wolves,
  porcupines, caribou,
  black bear,
  crossbills

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Temperate Forest

• south of Taiga
• has definite seasons
• most of US, N S America, Europe
  and Asia
• 100 cm precipitation yearly
• mixture of trees
  (pines
  and hardwoods-deciduous trees)
• plants shed leaves in winter,
• Animals- Deer, opossum, black bear,
• fox, squirrel, many bird species
  and
  insects

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Tropical Rainforest

• equatorial
• almost constant temperature of 25 oC
• gt 250 cm of rain fall or more yearly
• very humid
• greatest diversity
• Central and South America  
• Plants- large variety, tree branches
  form canopy,
  vines
• Animals-Toucans, monkeys, gorilla,
  tree frogs, snakes,
  lizards, parrots

20
Grasslands

• steppe, plains, or prairie
• West of Mississippi
• Uneven rainfall 25-75 cm
• Plants- Scattered trees,
  grass
  varies in length
• Animals-Bison, antelope,
• gophers, jackrabbits, sheep

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Desert

• less than 25 cm of rainfall yearly
• long droughts
• Can have high or low temperature
• W US, Africa, India, Asia, S America
• sparse vegetation
• Plant adaptations for survival
• shallow root systems absorb
  little rainfall
  quickly
• stems can photosynthesize,
• leaves modified to needles
• waxy cuticle
• Cacti
•  Small animals- lizards, kangaroo rat,
  scorpions, snakes