Transcript sss bio3.1 chngs in ec notes

Chapter 3 Ecosystems continually change over
time
3.1 How Changes Occur Naturally in Ecosystems
p.108 – 121
Words to Know:
Adaptive radiation
Climax community
ecological succession
natural selection
(c) McGraw Hill Ryerson 2007
3.1 How Changes Occur Naturally
in Ecosystems
Q. How are individuals in a species the same or different?
Natural selection - process where individuals with advantages are
better able to reproduce and pass along their traits.
 A salmon with a smaller tail may never have a chance
to spawn because it can’t swim to the correct location.
See pages 108 - 109
(c) McGraw Hill Ryerson 2007
3.1 How Changes Occur Naturally
in Ecosystems
Q. How are individuals in a species the same or different?
Natural selection - process where individuals with advantages are
better able to reproduce and pass along their traits.
 A salmon with a smaller tail may never have a chance
to spawn because it can’t swim to the correct location.
See pages 108 - 109
(c) McGraw Hill Ryerson 2007
3.1 How Changes Occur Naturally
in Ecosystems
Q. How are individuals in a species the same or different?
Natural selection - process where individuals with advantages are
better able to reproduce and pass along their traits.
 A salmon with a smaller tail may never have a chance
to spawn because it can’t swim to the correct location.
See pages 108 - 109
(c) McGraw Hill Ryerson 2007
How Organisms Adapt to Change
Natural Selection: An example.
Galapagos Islands (off the coast of Ecuador)
most famous example of natural selection.
Finches: There are 13 species on the island…
See page 110
(c) McGraw Hill Ryerson 2007
 All the species are descended from one finch species on the
mainland.
 Each species has unique characteristics that allows
them to thrive in their own niche, and not compete with
other finches for resources.
• Adaptive radiation - a form of natural selection
when many different species appear from
one original species.
(c) McGraw Hill Ryerson 2007
ECOLOGICAL SUCCESSION
ECOLOGICAL
SUCCESSION
Changes in the biotic
characteristics in an
area over time.
Primary
Succession
Secondary
Succession
See pages 111 - 113
(c) McGraw Hill Ryerson 2007
PRIMARY SUCCESSION #1
1. Primary succession
Starts with bare rock.
Wind carries spores of lichens that can survive on bare rock.
Weathering breaks down rock  soil begins to form.
(c) McGraw Hill Ryerson 2007
PRIMARY SUCCESSION #2
Pioneer Species are the first organisms to survive and reproduce.
improve soil 
other plants can grow 
animals appear 
form a mature community
(stable and change slowly)
(c) McGraw Hill Ryerson 2007
PRIMARY SUCCESSION #3
See page 114
(c) McGraw Hill Ryerson 2007
SECONDARY SUCCESSION #1
2. Secondary Succession:
When an area already has soil, but has had a disturbance like a
forest fire or clearcut.
Happens more quickly because there are already seeds, insects,
worms etc. in the soil.
(c) McGraw Hill Ryerson 2007
How Natural Events Affect Ecosystems
• Disturbances that affect mature communities.
1. Flooding
 Usually occurs in locations where water levels can change
rapidly.
 Leads to soil erosion, spread of pollutants and harmful bacteria
associated with sewage.
See pages 115 - 116
(c) McGraw Hill Ryerson 2007
 Climate change and global warming may be increasing
incidents of flooding.
 A tsunami occurs when huge waves, from large earthquakes,
flood coastal areas.
(c) McGraw Hill Ryerson 2007
2. Drought
 Occurs when an area receives a lower than average amount of rainfall over a
very long period of time.
 Prolonged drought can have severe effects on organisms.
(c) McGraw Hill Ryerson 2007
How Natural Events Affect Ecosystems
(continued)
3. Insect infestations
Most insects are helpful, but when normal conditions change,
infestations can occur.
Example: Mountain Pine Beetle:
Usually it is not a problem…it helps remove old trees, but….
See page 117
Take the Section 3.1 Quiz
(c) McGraw Hill Ryerson 2007
…in our forests there are a lot of old trees, the climate is warming,
and the bugs are not dying in the winter.
Pine beetle has blue stain fungus in its mouthparts, which it
transmits to the trees (symbiotic relationship).
Fungus slows down resin production on trees so the beetle can eat
the tree more easily.
(c) McGraw Hill Ryerson 2007