Transcript Biological Resistance Notes (15.2)

Biological Resistance (15.2)
State Standard
SB5E. Recognize the role of evolution to
biological resistance (pesticide and
antibiotic resistance)
Chapter 15
15.3 Natural Selection-Speciation-Resistance
Antibiotic Resistance
 Bacteria reproduce quickly and their
population grows rapidly.
 Mutations can lead to traits that allow certain
individuals to be immune to antibiotics.
 These survivors then reproduce quickly
(cloning themselves) and establish a
population of antibiotic resistant bacteria.
Ch. 15
15.3 Natural Selection-Speciation-Resistance
Antibiotic Resistance Cont’d
Ch. 15
15.3 Natural Selection-Speciation-Resistance
Antibiotic Resistance Cont’d
 The overuse of antibiotics has caused
antiobiotic-resistant populations of bacteria to
become a dangerous problem.
 Methicillin-resistant Staphylococcus aureus (MRSA)
is a bacterium that causes infections in different
parts of the body. It's tougher to treat than most
strains of staphylococcus aureus -- or staph -because it's resistant to some commonly used
antibiotics
Ch. 15
15.3 Natural Selection-Speciation-Resistance
Antibiotic Resistance Cont’d
Typical
appearance
of MRSA
infection
Ch. 15
15.3 Natural Selection-Speciation-Resistance
Pesticide Resistance
 Pesticides may kill most members of an insect
population, but variation allows some
individuals to be immune to pesticides.
 Those who are immune are able to survive
and reproduce, passing their immunity trait to
the next generation.
 Soon, a whole population of pesticideresistant insects is thriving.
Ch. 15
15.3 Natural Selection-Speciation-Resistance
Pesticide Resistance
• Overuse of
pesticides has allowed
more and more
resistant populations
to develop.