of the evolution theory
is a Latin word
for continuous, unidirectional change
idea of organic evolution states that all life form on Earth is descended from
other life, through small changes. In other words all life is linked by a
process of ancestry and descent. This observation goes back at least as far as
the Greeks in the fifth century B.c., who realized that all animals were built
on a common plan. In some of the Greek philosophers thought the idea of “everything changing” was a basic
the dominance of the church in Western thought obeyed the thout of evolution for
over a thousand years. According of Christian belief, all plants and animals
were created as we see them today and there is no possibility
that species could change.
the 1700’s it become more and more difficult for scientists to stay with this
static view of nature with their expanding knowledge of the biological world:
Linnaeous made the first standardized classification of organic species, there
were no more than 8000. However lots of discovery trips brought 100’s of new
questions have emerged!!!!
could all of these animals have fit onto Noah’s ark?;
did faraway places such as Australia and
South America have their own unique type of animals?
every kind of animals on earth had dispersed from mountain Ararat (Turkey) why
did no European type animals ended up in Australia?
is your opinion? Do you have the answer to these questions??
Questions related to geology
by the early 1800’ demonstrated that some of the animals were
extinct. (Big animals such as Mastodon, which are much bigger than any of
the animals exist today. This was an evidence nobody could hide).
soon after demonstrated that the species which become extinct soon had been
replaced with other species. How could this be explained by genesis, which
states that all species were created once.
soon came up with the idea that genesis could not explain the fossil record, but
they had no other explanation for it!!!!!
is your opinion? Can you explain
Buffon (1707-1788) French zoologist (molten ball guy)
big steps for the conception of evolution
was the first to state the concept of
species and noted that each species exists as a separate entity and he
demonstrated that no species could interbreed with another.
also noted that the environment directly caused variations in the offspring.
With this he was the first to realize the
interrelationship between environment and species. (Later ADAPTATION)
noted that there are also changes due to inheritance
of characteristics from both parents (INHERITANCE)
- He put these two
concepts together and come up with the statement that modification of organisms
are due to inheritance of characters and changes caused by the environment.
this fundamental statement, however he could not and did not explained how these
changes had happened?
Darwin Britain (Charles’ grandfather)
strongly influenced by Buffon’s ideas. As an animal experimenter
saw, that there are many changes going on during ONTOGENY (the development of an
saw that in breeding, changes can be recognized from generation to generation,
although these changes are very small.
also realized that the species become adapted to their environment primarily by
gathering food, (elephant’s trunk: tear the grass and lifting it to mouth), or
by security (protective coloration, wings, shells, legs)
Baptist Lamarck (1744-1829)
the greatest naturalist in the eighteenth century.
of modern invertebrate zoology
was the first to see all life -both plant and animal- as an integrated whole and
he used the term BIOLOGY for it.
He named first the inheritance of
other words this states that the effect of environments could be inherited by
found a mechanism for this theory. (The change of the environments will lead to
changes in needs of the organisms. Animals have to change their habits). How did
giraffes get the long neck?
Darwin 1809 February 12 (he
was born on the same day with Abraham Lincoln)
student at the Universuty of Edinburghwhen he learned medicine and natural
student, and finished college in a Christ college in Cambridge.
was always interested in natural science and collected animal, plant and rock
was from a wealthy family so he did not have to have a specific job, however his
father wanted him to have a job.
he was 22 there was a great opportunity for him. He could be the company as a
naturalist of the captain on a voyage on H.M.S. Beagle around the earth.
During the trip he collected a huge amount of species from different plants and
animals. He also made tremendous amount of observation in his notebooks. These
gave him the basis for his later publications and his theory of evolution.
saw the fantastic variety of species found on the earth,
huge population of different species.
amount of competition among population for food. (STABLE number in populations)
saw that not all offspring survives, but the ones the best fit for the certain
collected enough data for his revolutionary hypothesis of
best fit for life survive
of Galapagos is his best evidence for this!!!
Branching organization of life
Linneaeus’s classification it was clear, that nature was organized into a
great hierarchy of groups nested within groups. In Darwin’s time this
structure was deduced from the obvious anatomical features of animal and plants.
generation striking proof of this branching structure has been added from
molecules in our body. Comparisons of the molecular structure of a great number
of organisms have repeatedly shown the same pattern of branching suggested by
with strikingly different functions are commonly built from the same basic
parts. (Forelimbs of vertebrate are used for many purposes:
they have the same underlying structure
of bones, muscles, and nerves.
is that? ---- Most likely they have the same common ancestor.
elements derived from a common ancestor are called homologous elements.
is your opinion? Is this really prove
that they had to have the same ancestor?
contrast structures, that perform the same function but are not derived from the
same evolutionary origin are known as analogous
(wing of birds or bat in vertebrates vs. wing of butterfly insects)
Vestigial structures and other imperfections
pointed out, that the nature’s imperfections are more revealing than the
examples of good design. He pointed out, that lots of animals have tiny
remnants, or vestiges, features which they no longer use.
splint bones that are remnants of ancient side toes
would these features exist on these organisms unless they evolved from animals
that once needed these organs?
is your opinion? Is this really prove
that they had to have an ancestor
which used those structures?
great German embryologist Karl Baer (1792-1876) showed
that the development of animals was powerful evidence of their ancestry.
they develop into fish, amphibians, or humans all vertebrate embryos start out
very similar, with gill slits and long tail. During the embryonic development in
case of higher order animals these organs would be lost.
would humans have embryos with gill and tail unless their ancestors also once
had these features?
embryonic development or ontogeny of
vertebrates retains so much of their evolutionary history, or phylogeny, that
Ernst Haeckel (1834-1919) German embryologist said:
RECAPITULATES EVOLUTION in other words the embryonic
development repeats the evolution.
course this is not happen step by step, but embryonic development is one of the
most important arguments for the reality of evolution.
is your opinion about ontogeny? How
can you explain, that it looks like that every
organism have the same organic plan?
regions of the world have unique animal and plant assemblages.
most striking fact of evolution is that on many continents unrelated animals
have evolved to occupy similar ecological niches.
- pouched mammals or marsupials
developed forms that are mimic those of wolves, cats, anteaters and so on. This
phenomena is the so called ECOLOGICAL
only logical explanation:
is on the other hand evidence for plate tectonics, that Australia broke apart
from the supercontinent Pangea, when the evolution was at that level
(marsupials). Later on in Australia the evolution there was different from the
way in the other part of the world.
is your opinion? Is this really prove
that tevolution has to exist?
can evolve very fast in a matter of hours in response to changes in their
environment. (Cold, flu)
belive that there are still questions in the mechanisms of evolution, but there
is no question that it has happened. We
do not clearly understand what gravity is, yet this does not change the fact
that objects fall toward the earth.
science of how inheritance takes place is called
Darwin’s time scientists knew little about how favorable variations were
father of genetics was actually a monk who lived in Austria (Chek republik today
Brunn) in a monestry, Gregor Mendel (1822-1884). He did experiment with pea
concluded that traits such as color are controlled by a pair of factors we now
he concluded that genes controlling the same traits occur in alternate forms or
one allele may be dominant over another (However the other is not lost, but can
come out later on) Since the environment is changigng probably when the other
allele comes out that could be more favorable for the given environment, and
become the evolutionary trend)
recieve one allele (gene) of each pair
from each parent.
cells of all organisms are contain threadlike structures called chromosomes.
Chromosomes are complex double-stranded helical molecules of deoxiribonucleic
acid (DNA). Specific segments of the DNA molecule are the basic hereditary
units, the genes.
number of chromosomes are specific for a single species but varies among
species. For ex. fruit fly has 8 chromosomes, humans have 46, and horses have
sexually producing organisms the production of eggs and sperm result when parent
cells undergo a speciel type of cell division called meiosis.
eggs and sperms contain only half of the chromosomes; in humans 23.
fertilized eggs however contain all 46 chromosomes and starts to the cell
division called mitosis that does not reduce the chromosome number.
genes are passed from one generation to the other and mutation can occur, and
any change occur in the sex cells is inheritable.
are random in respect to fitness
be harmful, neutral or beneficial.
one is harmful which is beneficial is depend on the environment.
is your opinion? Now what is your opinion about evolution?
Mechanism of Evolution
know that in each population of different species there is an enormous potential
for variation. Think of humans!!!!
already talked about mutations.
of these variations are the result of interaction between individuals and the
surrounding environment and it is due to factors such as food suply, living
habitat, temperature, sunlight, and rainfall.
variations are genetic in origin and is due to the somewhat different genetic
make-ups of the individuals in the population.
total genetic information that codes for an
Phenotype--- The anatomical
results of growth and development from a given genotype.
is no population in the earth in which the genotypes and phenotypes of all
individuals are identical. All populations include some genetic variability
among its members. (difference in sex is an example of genetic variation).
the fact that all or most populations display genetic variability, not all
individuals are equally survive. Especially important the success in
plants and animals that are succesfull breeders are the ones passing on their
genetic characters to the next generation.
several mutations may result in individuals that are more successful in adapting
to small changes in the environment or in breeding. These individuals will pass
on their genetic features to an incresingly larger proportion of the population.
The particular mutations that confer these advantages will spread and fixed into
more and more individuals. This process is called natural selection.
selection results in a slow continuing shift in the genetic make-up of a
population. Given enough time this process can change the gene pool of a
population to probably call it a new
species, when the original and the new would not interbreed with each other.
gradual change through time of one species population to another phenotypically
distinct population is called PHYLETIC
EVOLUTION, or PHYLETIC GRADUALISM. (Phylogeny is the study of
ancestral-descendant relationships among organisms). THIS IS THE MODEL DIAGRAM
is an other wiev, punctuated equilibrium
holds that a species changes a little or not at all during most of its history
and than evolves rapidly to give rise to a new species. Long periods of
equilibrium are occasionally punctuated by
short periods of rapid evolution. It looks like that the fossil record support
we must know that the deposition is not continuous; thus the lack of
transitional forms is simply the artifact of the fossil record.
new species without transition can be a result of what is called ALLOPATRIC SPECIATION In order for these speciation events to
occur a segment of the population must be geographycally isolated!!!!!
the third, and probably the most important facet of this mechanism is ISOLATION,
especially geographyc isolation.
range, land barrier, periphreral isolates;
evolution happens when an interbreeding population gives rise to diverse
descendant types of organisms. Divergence into numerous related types involves
an ADAPTIVE RADIATION which occurs
when species of related ancestry exploit different aspects of the environment
(Finches of the Galapagos)
divergent evolution leads to organisms that different markedly from their
ancestor, Convergent and parallel evolution are processes where similar
adoptations arise from different groups.
of similar characteristic of distantly related organisms
of similar characteristic of closely related organisms
organisms are mosaic of characteristics, some of which are retained from the
ancestral condition, while others are more recently evolved.
like teeth, tail, hind limb, and brain size but!
and wishbone charact. of birds
the group of living things have trends in their evolution
really common trend is increase in size.
of vestigials so on.
fossils --- no
change ever!!!!!! Gingko
specimen evolves into an other gradually -- Pseudoextinction
termination with no continuation ------extinction