Download Chapter 3.1: Changes occur Naturally In Ecosystems Natural Selection

Chapter 3.1: Changes occur Naturally In Ecosystems
Natural Selection: Organisms (species) adapt to changes in the biotic and
abiotic factors in their environments. Charles Darwin “survival of the Fittest”
Galapagos island finches: each island has a unique ecosystem (biotic and abiotic)
The finches adapted to survive and reproduce on each island.
Adaptive radiation
Lake victoria in Africa has more than 300 species of cichlid. All of these species
formed from a single species.
Adaptations of Fish in Aquatic Environments
Adaptations in Aquatic Environments
Natural Selection: Every generation certain
members of a species have characteristics
that allow them to be more successful at
reproducing. More offspring are born with
these beneficial traits.
Adaptive Radiation: One species will adapt
to survive and occupy different niches.
Each finch evolved from a common ancestor
1. What is Natural Selection?
2. What is adaptive radiation?
Ecological Succession: Changes that take place over time affecting the type of
Organisms that inhabit a specific area
Primary Succession: this occurs when no soil is present. An example would
Be a receding glacier leaves exposed rock as it melts away.
Lichen spores spread by rain and wind begin to grow and inhabit rocks.
Lichens and erosion begin to break down the rock forming soil. Eventually mosses
Are able to survive.
Pioneer Species: the first organisms that are adapted to survive in these
Nutrient poor environments.
Secondary Succession: After a forest fire or a building is destroyed bare soil is
Exposed. This soil is full of organisms and nutrients which will occur much faster
than primary succession.
Climax Community: Both primary and secondary
succession lead to a mature community such as
(boreal forest, tropical rainforest, temperate
deciduous forest, grassland).
These communities can remain stable over long
periods of time.
They do however continue to change as
climate changes.
(Abiotic and biotic factors are always changing)
Ancient Forest is one
hour from Prince
George (2000 year
old cedar trees).
Biodiveristy hot spot
Natural Events Affect Ecosystems: Volcanoes, Forest Fires, Flooding, tsunamis
Insect infestations, drought
Pine Beetle Kill will affect nutrient
Cycles and biodiversity in this
lodgepole ecosystems.
Forest fires and winter temperatures
below -300C use to control pine
beetle populations
Today humans prevent forest fires
which were part of a natural cycle
allowing pine beetle populations to
grow.
This also affects humans because
We loose trees for forestry
Reading Check 12 minutes
• What is ecological succession?
• Briefly describe the process of primary
succession
• What is a mature community?
• How does secondary succession occur?
Explain how primary succession
Compares to secondary succession
In terms of the following
A) The amount of soil available
_______________________________
Why are lichens considered to be pioneer
species? __________________________
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B) The amount of nutrients available
______________________________
C) The rate of succession
_______________________________