Download Classification and Adaptation

 Charles Darwin (1809-1882) was an English
scientist who sailed all over the world on the HMS
Beagle.
 Darwin became curious about the diverse
creatures that he saw and the possible
relationships between them.
 Natural Selection occurs when organisms with
certain traits survive, reproduce, and pass on
those traits to the next generation.
 Ex: A faster fish may be better suited for escaping
predators and live to produce offspring with that same
variation
 This is often described as “Survival of the Fittest”
Overproduction of offspring – having many
offspring raises the chance that some will survive
2. Variation and Adaptation
1.
1.
A heritable trait that increases and organisms
ability to survive is an adaptation.
Survival of the ‘Fittest’
3.
1.
Those best suited for an environment will survive
and reproduce.
Descent with Modification
4.
1.
More individuals will have the successful traits in
future generations, as long as those traits are
beneficial.
 All the genes, including different alleles, in a given
population is called the “gene pool”
 Diversity within a species makes it more likely that the
right adaptation could be present – therefore, an
increase in diversity increases its chances of survival
**How do you get diversity in a population…???**
1.
Genetic Drift - the random change in the
frequency of alleles of a population over time.
Due to chance, rare alleles in a population will
become eliminated; other alleles will increase in
frequency and become fixed.
2. Gene Flow - the movement of genes into or out
of a population.
3. Non-random Mating – Mating among
individuals with favorable traits
» such as coloration in plants and animals,
competitive strength, courting behaviors etc.
4. Mutations – changes in DNA
increase the frequencies and types of allele
5. Natural Selection – Since only the ‘fittest’
organisms survive, they will influence which genes
are passed down to future generations.
 Speciation is the process of forming a new species by
biological evolution from a preexisting species
Adaptive Radiation/Divergent
Evolution: - a number of different species diverge
(split-off) from a common ancestor. in different
niches.
Convergent Evolution – Unrelated organisms in
similar environments may evolve adaptations to
similar niches.
Coevolution - when two or more species living in close
proximity change in response to each other. The
evolution of one species may affect the evolution of the
other.
Extinction - the elimination of a species often occurring
when a species cannot adapt to a change in its environment.
This can be gradual or rapid.
 Gradual extinction - occurs at a slow rate and may be due to other
organisms, changes in climate, or natural disasters.
 Mass extinction - occurs when a catastrophic event changes the
environment very suddenly (such as a massive volcanic eruption,
or a meteor hitting the earth causing massive climatic changes). It is
often impossible for a species to adapt to rapid and extreme
environmental changes.
 The changes in inherited traits in a species over time is
called biological evolution.
 Microevolution occurs on a small scale affecting a single
population
 Macroevolution occurs on a large scale affecting changes in
species across populations
 The species we see today evolved from species of former periods
of time.
 Other Evidence of Evolution
 Paleontology
 Anatomy
 Embryology
 Biochemistry
 Paleontology is the study of prehistoric life
 Fossils are preserved remains of organisms that lived
many years ago
 The fossil record provides evidence of life forms and
environments and supports evolutionary relationships by
showing the similarities between current species and
ancient species.
 Anatomy is the study of the structures of organisms
1. Homologous Structures have similar characteristics
resulting from sharing common ancestry
 The greater the numbers of shared homologous structures between
two species, the more closely the species are related2.
2. Analogous Structures reveal that species living in
different locations under similar ecological conditions
may evolve similar
ex. Butterfly and Bird Wings
3. Vestigial Structures serve little or no function in the
organism
 The vestigial organs of one specie are often homologous
with structures in a related specie that still uses the
organ.
 Embryology is the study of embryo development in
organisms
 The could include pre-birth, pre-hatching, or pre-germination
 Studying the structures of embryos can lead to clues of
possible ancestors
 The embryos of fish, reptiles, birds, and mammals all have
a tail and gill slits even though they may not exist on the
mature organism
 The more similar the DNA and amino acid
sequences in proteins of two species, the more
likely they are to have diverged from a common
ancestor
 All citrus trees can produce citric acid
and therefore may have developed
from a common ancestor
 The study of the ability of different species
to synthesize similar substances is called
comparative biochemistry
the relationship of different
organisms believed to have a
common ancestor based on
taxa (groups)
 Branches from an
intersection show those with
a common ancestor
 You can see that the snail,
earthworm and insect have a
more recent common
ancestor than the snail and
sea star
Time
 A Phylogenetic Tree shows
 All living things can be classified as belonging to
one of 3 Domains
 Bacteria
- Archaea
- Eukarya
 All living things can be classified as belonging to
one of the 6 Kingdoms of Life






Archaeabacteria
Eubacteria
Protista
Plantae
Fungi
Animalia
 Biologists identify and organize organisms through
Taxonomy- a classification of organisms based on
shared characteristics.
 To work, the system needs to be universal across the
scientific community and everyone needs to follow the
same rule for naming a specie.
 At first, scientists tried to use Greek or Latin but the
interpretations often didn’t work well.
 Carolus Linnaeus developed a two-part naming system
called Binomial Nomenclature.
 It uses the Genus and Specie of an organism to identify
it.
 EX: Polar Bear would be called Ursus maritimus
Red Fox
Organism
Kingdom
Animalia
Animalia
Animalia
Animalia
Animalia
Phylum
Chordata
Chordata
Chordata
Chordata
Chordata
Class
Mammalia
Mammalia Mammalia
Mammalia
Mammalia
Order
Carnivera
Carnivera
Carnivera
Carnivera
Rodentia
Family
Felidae
Canidae
Canidae
Canidae
Geomyidae
Genus
Felis
Vulpus
Canis
Canis
Thomomys
Species
domesticus
fulva
familiaris
lupus
bottae
A dichotomous key is a tool that allows the user to determine the
identity of items in the natural world, such as trees, animals, or rocks.
Keys consist of a series of choices that lead the user to the correct name of
a given item. "Dichotomous" means "divided into two parts". Therefore,
dichotomous keys always give two choices in each step.
1. a. wings covered by an exoskeleton ………go to step 2
b. wings not covered by an exoskeleton ……….go to step 3
2. a. body has a round shape ……….ladybug
b. body has an elongated shape ……….grasshopper
3. a. wings point out from the side of the body
……….dragonfly
b. wings point to the posterior of the body ……….housefly
 When there is no change in the allele frequencies
in a species, the population is in genetic
equilibrium.
 This concept is known as the Hardy-Weinberg
Principle. To sustain equilibrium, the must be:
 A very large population with no genetic drift
 No movement into or out of the population
 Random mating
 No mutations with the gene pool
 No natural selection
Godfrey Hardy
(1877-1947)
Wilhelm Weinberg
(1862-1937)