Download Big Idea 1: Evolution

Natural selection acts on phenotypic variation in population (1.A.2)
Big Idea 1: Evolution
a. Environments change and act as selective mechanism on
Change in the genetic makeup of
a population over time is
evolution. (1.A.2.)
PowerPoint® Lecture Presentations for
Biology
Eighth Edition
Neil Campbell and Jane Reece
23.1, 23.4
AP Biology Curriculum 2012-2013
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
populations.
– Industrial Melanism: increase in the frequency of a darker
phenotype in response to pollutants
• Prior to the Industrial
Revolution in England the
frequency of the dark allele
was about 0.01%
• By the 1895, the number of
dark-colored moths was at
98%
• Modern times, because of
cleaner air standard in
Europe, the dark-bodied moth
is becoming less frequent.
Peppered Moth Evolution
YouTube - Bozeman Biology:
Natural Selection (11:00 min.)
YouTube - Bozeman Biology: Unit 1
Review - Natural Selection (13:00 min.)
http://www.youtube.com/watch?
v=R6La6_kIr9g&feature=plcp
http://www.youtube.com/watch?
v=sBM9ZKTQ1PQ&feature=plcp
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Natural selection acts on phenotypic variation in population (1.A.2)
b. Phenotypic variations are not directed by the environment but occur
– Flowering time in relation to global climate change
through random changes in the DNA and through new gene
combinations
• As a result of climate
change, many plants
are now flowering
measurable earlier
than they did in the
past.
Average (red line) and 95% uncertainty range (grey area) of the
estimated first flowering index (day of the year). The black lines
indicates the average for every 25 years and the dotted line for
the orst recent 25 years (Amano 2010)
Natural selection acts on phenotypic variation in population (1.A.2)
• 5.0 days earlier for
every 1°C increase
in temperature
– mutations: the ultimate source of new alleles
• low in plants and animals, averaging about one mutation in
every 100,000 genes per generation
• even lower in prokaryotes and viruses but with short
generation spans mutations can quickly generate genetic
variation
– sexual reproduction: three mechanisms contribute to gene
shuffling are:
• crossing over
Proceedings of The Royal Society
A 250-year index of first flowering dates and its response to temperature change (Amano et al 2010)
http://www.skepticalscience.com/Flowers-blooming-earlier-now-than-any-time-in-last-250-years.html
• independent assortment of chromosome
National Center for Biological Information Resources (NCBI)
• fertilization
Global warming and flowering times in Thoreau’s Concord: a community perspective - Abstract
http://www.ncbi.nlm.nih.gov/pubmed/18409423
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Natural selection acts on phenotypic variation in population (1.A.2)
Natural selection acts on phenotypic variation in population (1.A.2)
– DDT resistance in insects
c. Some phenotypic variations significantly increase or decrease
fitness of the organism and the population.
Fig. 23-17
– Sickle cell anemia
• Heterozygotes are
protected against
the most severe
effects of malaria
• This protection is
important in tropical
regions where
malaria is a major
killer
DNA Tube
Natural Selection in Humans
(15:00 min.)
http://www.dnatube.com/video/11930/
Natural-Selection-in-Humans
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Insecticide
application
Chromosome with gene
conferring resistance
to insecticide
Frequencies of the
sickle-cell allele
0–2.5%
Distribution of
malaria caused by
Plasmodium falciparum
(a parasitic unicellular eukaryote)
2.5–5.0%
5.0–7.5%
7.5–10.0%
10.0–12.5%
>12.5%
Additional
applications of the
same insecticide will
be less effective, and
the frequency of
resistant insects in
the population
will grow
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Survivor
Natural selection acts on phenotypic variation in population (1.A.2)
Natural selection acts on phenotypic variation in population (1.A.2)
d. Humans impact variation in other species.
– Artificial Selection
– Artificial Selection
• These different
vegetables have all
been selected from
one species of wild
mustard. By
selecting variations
in different parts of
the plant, breeders
have obtained these
divergent results.
Fig. 22-9
Terminal
bud
Cabbage
• Breeding of domesticated animals
Lateral
buds
Flower
clusters
Brussels sprouts
Leaves
Kale
Cauliflower
German shepherd
Yorkshire terrier
English springer Mini-dachshund
spaniel
Hundreds to
thousands of years
of breeding
(artificial selection)
Wild mustard
Flowers
and stems
Broccoli
Kohlrabi
Ancestral dog
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Natural selection acts on phenotypic variation in population (1.A.2)
– Overuse of antibiotics
• Mycobacterium
tuberculosis
PBS Evolving Ideas - video 6
Why Does Evolution Matter Now (7:00 min.)
http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html
http://www.youtube.com/watch?v=6jBD8xfbf4Y
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Golden retriever
Stem
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Figure 13.4B