Transcript Loss of Diversity

4.2.1 Loss of Diversity
Mrs. Page 2014-2015
Assessment Statements
4.2.1 Identify factors that lead to the
loss of diversity.
Natural Disasters
Volcanic Eruptions
Floods
Tornados or Hurricanes
Droughts
Natural Disasters
Forest Fires
-Lead to primary or
secondary succession
- Initial loss of diversity leads
to little competition
- Diversity increases through
intermediary stages
- Once climax community is
reached diversity again
decreases.
Human Habitat
Degradation
 Fragmentation
–
isolates organisms
reducing
reproduction (genetic
diversity decreases)
 Loss
of habitat leads
to decrease in species
diversity
Agricultural Practices
Monocultures
Crop Rotation
Agricultural Practices
Monoculture
Crop Rotation
- Little genetic diversity
- More genetic diversity
- Depletes soil of nutrients
requiring use of fertilizers
- Allows natural nutrient cycling
- Fertilizers lead to water
pollution
- No water pollution due to
chemical fertilizers
- Often require pesticides (1
infestation can wipe out whole
crop)
- Natural diversity limits need for
pesticides
- Genetically modified crops
increase yield
- Natural gene flow
Pesticide Use

Pesticides are poisons to kill
living things

Often affects more than just
insects

May lead to pesticide resistant
insects
Genetically Modified
Organisms (GMO’s)
-Creating “superbugs”
- Decreasing bee, butterfly and
other beneficial pollinator
populations
- Decreases biodiversity – all
crops same genetics
(monoculture) to have
“benefit” of modification
Disease
• Forest pests and disease have seriously
harmed the environment and have
imposed significant cost to the
economy.
• Exotic pests and pathogens, such as the
chestnut blight, Dutch elm disease, and
pine beetle infestations have had a
profound effect on Eastern forests.
• Management of these pests and
diseases has been impacted by a variety
of factors such as forest fragmentation,
increasing human population, and the
expansion of invasive species.
Dutch Elm Disease
Pine Beetle Infestation
Non-native (invasive)
Species
Organisms not native to an area
that are brought in by humans
or get out of confinement.
 These invaders cause massive
disruptions in ecosystems by
competing for resources and
reducing biodiversity
 This causes an imbalance in
equilibrium and they often
dominate and wipe out the
native species.

Invasive Species
Pollution
Hunting, Collecting,
Harvesting
Funny but not…