Transcript Natural Selection in Response to Introduced Plant

Please help yourself to a drink in the back
of the room. We are going to be using the
bottles as planters.
Chapter 19
Direct Observations of Evolution by
Natural Selection
You Must Know
• Examples of direct observation of evolution by
natural selection.
Concept 19.3: Evolution is supported by an
overwhelming amount of scientific evidence
• New discoveries continue to fill the gaps
identified by Darwin in The Origin of Species.
• There are four types of data that document the
pattern of evolution.
– Direct observations
• natural selection in response to introduced plant species
• evolution of drug-resistant bacteria
– Homology
– The fossil record
– Biogeography
Natural Selection in Response to Introduced Plant Species
Soapberry bug with beak
inserted in balloon vine
fruit. The balloon vine is
native to Florida.
Soapberry bug with beak inserted in
goldenrain tree Fruit. The goldenrain
tree was recently introduced from Asia
Figure 19.14b
Number of individuals
Results
10 On native species, Beak
8 balloon vine
6 (southern Florida)
4
2
0
Museum-specimen average
10
8
6
4
2
0
On introduced
species,
goldenrain tree
(central Florida)
6
7
9
8
10
Beak length (mm)
11
The bacterium Staphylococcus
aureus is commonly found on
people’s skin or in their nasal
passages.
Methicillin works by
inhibiting a protein used by
bacteria in their cell walls.
Evolution of
drug-resistant
bacteria
Annual hospital admissions
with MRSA (thousands)
The rise of methicillin-resistant Staphylococcus aureus (MRSA)
400
350
300
250
200
150
100
50
0
’93 ’94 ’95 ’96 ’97 ’98 ’99 ’00 ’01 ’02 ’03 ’04 ’05
Year
• Natural selection does not create new traits, but
it selects for traits already present in the
population.
• The local environment determines which traits
will be selected for or selected against in any
specific population.