Download Changes to the Environment

Changes to the Environment
Succession
• Population interact to form a
• Pioneer community – the first
constantly changing community
community to inhabit a new location
• Populations must adapt to
changing conditions
• Ecological succession – the
orderly change in the makeup of
a community over time
Pioneer Community
Harsh environment
Increasing biomass
Inefficient energy consumption
Nutrient loss
Low species diversity
Fluctuations common
• Climax community – an established
community that undergoes little change
Climax Community
Favorable environment
Stable biomass
Efficient energy consumption
Nutrient cycling
High species diversity
Fluctuations uncommon
Primary Succession
• Primary succession – occurs in newly formed areas where no
organisms existed before
• Ex) Volcanic Eruption
1. Lichens and mosses colonize rocks
2. Lichens dissolve rock, forming soil
3. As lichens/mosses die, they add organic matter to the soil
4. Rich soil supports small animals, insects, and more plants
5. Barren rock becomes a terrestrial ecosystem
Biology 13.3 – Changes to the Environment
Changes to the Environment
Secondary Succession
• Secondary succession – occurs after a preexisting climax
community has been partially or completely destroyed
• Natural disasters
• Land cleared for harvest or construction
• Occurs where soil is already present
• Ex) Abandoned cleared field
1. Weeds are pioneer species
2. Dying weeds add nutrients to the soil
3. New plants thrive, creating shade
4. Pine forest becomes the climax community
Soil
Changes to Ecosystems
• Populations depend on each other
• Change that affects one population
can destroy the entire ecosystem
• Ex) Kelp forest ecosystem
Pioneer
species
Primary Succession
None
Autotrophic prokaryotes
Lichens
Mosses
• Survival of a species
• Dependent on maintaining
population size
• Must adapt to changes in
limiting factors
• Food
• Water
• Space
• Affects biodiversity
Secondary Succession
Present
Herbaceous plants
• Biodiversity – includes the variation
in life within a given species,
ecosystem, biome or on earth, along
with the complex interactions
occurring among species
• Currently decreasing
• Decline affects all life
Biology 13.3 – Changes to the Environment
Changes to the Environment
Role of Humans
• Clearing land
• Destroys ecosystems
• Removes trees that absorb
CO2
• Coal-burning machines
• Releases CO2
• Increased CO2
• Greenhouse effect
• Global climate change
• Loss of biodiversity
• Biomagnification – an effect in
which the concentration of
pollutants in a food chain
dramatically increases with each step
up in trophic levels
• Dams
• Displace communities
• Increase water-borne diseases
• Increase greenhouse gasses
• Block fish migrations
• Increase erosion
• Cause loss of species
• Burning of fossil fuels
• Releases CO2 and nitrogen
• Greenhouse effect
• Global warming
• Acid rain
• Affects soil and water
• Kills plants
• Excessive irrigation
• Erosion depletes
nitrogen from soil
• Poor plant growth
• Fertilizers
• Excess nitrogen
• Affects soil and water
• Algal blooms reduce O2
• Kills aquatic life
• Decrease biodiversity
• Overhunting
• Introduced animals
• Spread disease
• Decimate natural
populations
Biology 13.3 – Changes to the Environment