Transcript Tropical Rainforest

Tropical Rainforest
Emergent layer
Canopy
Understory
Forest floor
Division of Layers
• Emergent Layer:
Contains the tallest trees in the rainforest(150~200 feet).
Windy, relatively dry, lots of sun.
• Canopy:
The primary layer of the rainforest(15~150 feet).
Sun, humidity, water, shelter, leaves, flowers, fruit.
• Understory:
Seldom grow to more than 12 feet.Difficulty with
pollinization because of the lack of air movement.
Filtered sun, high humidity, lack of air movement.
• Forest Floor:
Almost no plants (because 0-2% light & 100% humidity).
Few flowering plants, mosses, herbs, and fungi.
Species Diversity
A mature tropical rainforest has
incredible diversity.
Why?
There are a variety of specialized niches
in distinct layers (based mostly on their
need for sunlight).
Biodiversity
Scales of organization
• genetic -- diversity of genetic information
found within species and populations
• species -- diversity of species
• community -- diversity of community
composition
• ecosystem -- diversity of assemblages of
communities (Fox River watershed)
• landscape -- diversity of assemblages of
ecosystems (Western Great Lakes)
Definitions:
• Sustainability or stability:
Maintained by a constant dynamic change in response to
changing environmental conditions.
Usually comes with high biodiversity.
• Persistence or inertia:
The ability of a living system to resist being disturbed or altered.
• Constancy:
Ability of a system (population) to keep its numbers within the limits
imposed by available resources.
• Resilience:
Ability of a living system to bounce back after an external
disturbance that is not too drastic.
Natural Extinctions
• Habitat Disruption
– Volcanic Eruptions
– Asteroid Impact
• Habitat Modification
– Climate Change
– Mountain-Building
– Sea Level Change
• “Exotic” Species
– Continental Drift
Things that Probably Don’t Cause
Natural Extinctions
• Epidemics
– Rapid co-evolution of disease and host
• Evolution of New Competitors in Place
– Existing organisms already well-adapted
Human-Caused Extinction
• Excessive Predation (Food, fur,
collecting, pest eradication, etc.)
• Habitat Destruction
• Destruction of keystone species
• Introduction of Exotic Species
– Competitors
– Predators
– Diseases
• Pollution and Contamination