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Transcript of Http:// ntents/data1/img4/mantis.jpg.
http://www.mediamob.co.kr/fds/blogcontents/data1/img4/mantis.jpg
WHAT IS THE DIFFERENCE BETWEEN A POPULATION
AND A SPECIES?
H
armful
A
daptive
N
o Value
Harmful – These types of mutations are detrimental to the organism
Either causing it to be less well adapted for its environment, or by causing a basic life function of the animal to function deficiently or not at all
www.ridacritter.com/ site_map.htm
http://www.ridacritter.com/albino%20sqhttp://www.moosefoundation.org/pictures/albino.jpgrrel%20005.jpg
http://www.ridacritter.com/albino%20squirrel%20http://www.weforanimals.com/free-pictures/wild-animals/moose/1/Bull%20Moose%20Resting%20in%20Vegetation%20-%20Burger,%20Carl%20-%20USFWS.JPG005.jpg
TAKE A MINUTE…
W
rite a brief list of how the albino organisms color
mutation is detrimental to that organism’s survival in
the wild.
A
daptive – These types of mutations cause the
organism to gain some advantage that increases its
ability to survive and reproduce successfully
A
daptive
E
xamples:
T
he ability to utilize another food source
D
isease immunity or resistance
M
akes the organism more competitive
E
xamples:
D
isease immunity or resistance
http://evolution.berkeley.edu/evosite/evo101/images/sicklecell.jpg
M
utations can make
the organism more
competitive
http://www.wonderquest.com/2003-01-31-giraffe-rhino.jpg
http://www.airs.com/ian/giraffe.gif
TAKE A MINUTES…
W
rite down a list of at few adaptations that the Giraffe
posses that increase its fitness within its
environments
N
o Value – These types of mutations do nothing to
either harm the organism or to make them more fit
M
utations assist a species because they cause a
variety of variations to exist within that species.
Adaptive mutations increase the fitness of a species
by providing increased variation
R
ecurrent mutation – a mutation for a trait that is
genetically different from either parent, but is
already present in the population
N
ovel Mutation – a mutation that results in a trait
that is not already present in the population
COMPETITION
C
onflict that arises between individuals or groups in
the process of acquiring limited resources
COMPETITION OCCURS BECAUSE OF….
L
imiting Resource
A
ny factor (usually a nutrient) within an ecosystem
that is in finite quantity and that is required by
individuals in that ecosystem for survival
TYPES OF COMPETITION
I
nterspecific - competition between different species
I
ntraspecific – competition within the same species
2 BIOLOGICAL IMPERATIVES
1
. Survive
2
. Reproduce
A
n organism is FIT if it accomplishes these 2 goals in that order.
I
n fact once an organisms has accomplished both goals that organism
will often expire soon for a variety of different reasons
FITNESS
“
The relative contribution an individual makes to the gene pool to the
next generation”
F
itness describes how successful an organism is at accomplishing the 2
biological imperatives.
C
ambell, Biology
TO CLARIFY…A
niche is what an organism does in its
community, its habitat is where it lives
http://www.job-interview-questions.com/executives.jpg
http://www.nypatriot.com/victorian-house.jpg
2
types
Fundamental niche – the resources (biotic and abiotic) that are
theoretically available to an organism
R
ealized niche – the resources (biotic and abiotic) that are actually
utilized by a given population
(Campbell, Biology)
COMPETITIVE EXCLUSION PRINCIPAL
• “Two species with similar needs for the same limiting resources cannot coexist in the same place” –Campbell, Biology
DARWIN’S OBSERVATIONS
1. If all offspring were able to reproduce successfully populations size would exponentially increase over a few generations
2. In natures populations sizes are relatively stable
3. Limited resources exist in all environments
4. Individuals within the same species have a variety of unique and distinct traits (every individual is different)
5. Many of these variations can be passed on to successive generations
WHAT THIS MEANS…
Competition results when more offspring are produced then can survive because resources are limited
Offspring that posses more beneficial characteristics are more likely to survive and pass on their genes
Because more fit individuals survive most often populations will shift over time to accumulate more beneficial characteristics
T
his is called….
NOTE
A
daptations are not static as environments change so
do the characteristics of a population. The best
combination of traits changes over time
N
ote: species do not develop a trait to cope with an
element in their environment rather a pool of traits
(range of variation) exist within a given population
and those that are best adapted survive more
frequently and reproduce more successfully.
ALSO NOTE
A
rtificial selection – human modification of species
(ex. Selective breeding)
Food
Habitat
Mates
Predation
Disease
Climate
Competition for resources ( invasive species)
NOTE…
O
nly traits that already exist in a population can be selected for
E
very adaptation is also a compromise
E
very adaptation has to be based on a preexisting element of the
organism
T
here cannot be a permanently perfect organism
The drive to reproduce can be strong enough in an organism to trump that organism’s drive for survival
INTRASPECIFIC NATURAL SELECTION…
http://scienceforfamilies.allinfo-about.com/zoo/peacock.jpg
A
feature possessed by a single sex that increases
reproductive fitness (generally in vertebrates)…
IMPORTANT
R
eproductive fitness can (but doesn’t have to) detract
significantly from the environmental fitness of an
individual ie.
T
he Peacock …
http://scienceforfamilies.allinfo-about.com/zoo/peacock.jpg
Please EAT ME!!
My big dumb
tail feathers
make me
easy to SEE!
And
easier to
catch!!!
NOTE
S
exual secondary characteristic can assist the animal
in survival such as a deer’s antlers, but it is often the
females that determine the fitness of a Sexual
dimorphism
ASEXUAL REPRODUCTION
“
the creation of new individual's whose genes all come from
one parents without the fusion of egg and sperm.”
-
Campbell Biology
E
ssentially Cloning the Parent
ASEXUAL REPRODUCTION
Organisms are well adapted to stable environments cloning maintains the “best combination for the current situation”
Less of a chance to introduce detrimental traits into the gene pool
No need to find or compete for mates (saves time and energy and can reproduce in isolation)
Can produce a large amount of offspring in a short amount of time
A
sexual reproduction is best suited to stable environments
in which individuals are already well adapted to survive
T
his is because the “best traits” are identically copied into
each successive generation
ASEXUAL REPRODUCTION
SEXUAL REPRODUCTION
“
the creation of Offspring by the fusion of haploid
gametes to form a zygote, which is diploid.”
-
Campbell Biology
SEXUAL REPRODUCTION
Adds more variety to the population so as a whole the
population is better situated to survive and prosper in rapidly
changing or new environment
B
est in new or rapidly changing environment
The Red Queen in “Alice in Wonder Land” had to run at full speed just to stay in the same place.
This means that “a species must continually evolve to survive in a world full of other evolving species” –the science of ecology
O
ne example are diseases. A cloned (or asexually
reproduced) population is highly susceptible to being
wiped out by a contagion.
P
redator prey relationships are another example
ADAPTIVE RADIATION
T
his process of modification over time to fill a variety
of niches is
TYPES OF NATURAL
SELECTION…
T
his type of selection encourages
the average or status quo
combination of traits.
I
t happens in environments
where there is little change
occurring
STABILIZING SELECTION
DIRECTIONAL SELECTION
T
his type of selection favors a specific
combination of traits that were relatively
rare in the original population
I
t happens in environments where there
is great change occurring or is a species
is moving into a new environment
DIVERSIFYING SELECTION
T
his type of selection favors traits on
either end of the spectrum but not the
middle
I
t happens in environments where there
is change but the new factors favor
multiple variations, this often happens
in a divergence of species
CONVERGENT EVOLUTION
W
hen unrelated groups have analogous but nonhomologous
features (wings in birds and butterflies, fins in squids and
seals), the process is called convergent evolution
(sometimes parallel evolution) - similar needs produce
similar structures, even if they're based on different
architecture. Both support the concepts of evolutionary
change by selection.
D
ue to similar selection pressures that are consistent
over long periods of time, unrelated organisms (or
distantly related ones) acquire similar traits to deal
with those similar pressures.
CONVERGENT EVOLUTIONA
NATOMY• HOMOLOGOUS STRUCTURES• ANALOGOUS STRUCTURES
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
http://evolution.berkeley.edu/evolibrary/home.php
PUT ANOTHER WAY…
I
t is “the emergence of numerous species from a
common ancestor introduced into a new
environment, presenting a diversity of new
opportunities and problems”
– Campbell, Biology
T
his happens in instances when there exist unrealized
opportunities in a new environment.
O
ver time once rare characteristics are emphasized and
beneficial. This s divergent or directional selection
depending on the circumstance
DIVERGENT EVOLUTION
T
raits with similar internal structure
are called homologous traits
W
hen homologous features become used
for different purposes - are no longer
analogous - the process is called
divergent evolution, the splitting of
a family tree in different directions.