Charles Darwin
The Father of the modern theory of evolution
who traveled the world on a ship as a naturalist
and recorded his observations
Evolution
the changes that occur in populations of
species over long periods of time
Example of Lamarck's theory of use and disuse.
Giraffe neck became longer
as it was needed to reach higher in the branches over time.
How does adaptation relate to evolution?
...individuals that have characteristics that are adapted to living in a particular environment survive and pass those traits on to their offspring.
Example of Natural Selection
Short necks died because they could
not reach tall trees.
What did Charles Darwin notice on his visits
to the Galapagos Islands?
Species on the different islands had different characteristics from those on the mainland due adaptations to the different environments
What is a vestigial organ?
an organ, such as the human appendix, that is
reduced in size and no longer has a function.
How are homologous structures used to
support evolution?
Bone structures that are similar in different species tend to indicate a common ancestor among them.
What are analogous structures?
Body structures that have the same function, but are not constructed the same way (bird wings have bones, but butterfly wings do not). These do not have common ancestor.
What is speciation?
the formation of a new species from an
existing one due to changes in the population.
How does natural selection work?
favorable traits (adapted to environment)
cause the individual to survive and reproduce.
The unfavorable traits die and the genes are lost
and are not passed on to offspring.
The main points of Darwin's theory of
evolution.
variations occur in populations
some are favorable variations
more offspring than can survive
favorable variations survive and reproduce
therefore, changes occur in populations over time
What is reproductive isolation?
When members of a species can no interbreed (mate) and produce fertile offspring. This can be the result of different mating seasons, difference in physical characteristics, or geographical separation. This leads to a new species.
What is genetic equilibrium?
when populations do not change over time. The gene pool remains stable and does not change. This may be
due to the following: random mating, large population, no movement of individuals in and out of population, no
mutations, no natural selection.
How does sexual reproduction lead to genetic variation?
the many different combinations of genes through the random fertilization of the egg provide offspring with varying traits.
How do similarities in early development support evolution?
similar embryo structure in different species have been used as evidence that the species evolved from a common ancestor
Explain what is meant by "survival of the fittest.
individuals that are best suited to their
environment survive and reproduce most successfully
How do fossils support evolution?
fossils in different layers of rock provide evidence of the way species changed over time.
The Grant's studied the size of finch beaks in the Galapagos Islands. What was their conclusion?
They related the different beak structures to different kinds of food supply over time among the different
islands. This also showed that the Galapagos finches evolved from a common ancestor.
What is a gene pool?
...the total number and kinds of genes in a
population of species.
What happens to the gene pool during
evolution?
.the unfavorable genes are lost through the death of individuals not adapted to the environment. The favorable
genes increase with new offspring. Thus, the gene pool changes.
What is gradualism?
..evolution that occurs slowly over time. Changes in the species occur at a slow constant rate.
What is punctuated equilibrium?
Long periods of no change are interrupted by short periods of
rapid change.
What is adaptive radiation?
A form of divergent evolution in which a species evolves into different species.
How are mutations connected to evolution?
mutations are changes in genes and chromosomes. They may be favorable or unfavorable. Those that are favorable will enable the individual to survive and pass those changes to offspring thus changing the population.
What kinds of gases do scientists believe were present in the early atmosphere of Earth?
ammonia, water, hydrogen, and methane
Explain the use of radiometric dating.
Radioactive elements decay at a known rate of time. They change into another element as they decay. Age of
rock in which the fossil is found is determined by comparing the percent of the original isotope remaining to that of the new element.
How do we determine the age of fossils?
Using relative dating. The age of fossils can be compared according to the layer in which they are found. The youngest fossils are found in the upper layers while the fossils in the lower layers are the oldest.
What did Miller and Urey prove in their experiment?
They proved that organic molecules could be formed from chemical reactions among the gases in the early
atmosphere instituted by lightening. Gases in a special chamber were given an electric spark and simple organic
compounds were collected in a condenser
How are proto-cells different from living cells?
have a semi permeable membranes
can store and release energy
What is the theory of endosymbiosis?
modern chloroplast and mitochondria were once prokaryotes that could carry out photosynthesis and respiration respectively and that lived symbiotically inside larger prokaryotes.
What are eukaryote cells? How did they
evolve?
They are cells that have organelles and nuclei. They evolved from a symbiotic relationship among other prokaryotes.
What were the first cells?
The first cells were prokaryotes (bacteria-type
organisms)
What gas was not present in the early
atmosphere? Why?
Oxygen was not present because there no photosynthetic organisms that could capture light and split water to release oxygen.
What was the significance of the formation of oxygen gas?
Oxygen was produced by primitive photosynthetic prokaryotes. Ozone was produced by chemical reactions
between oxygen molecules and lightening. Ozone layer formed protective layer form UV radiation making it possible for life to evolve and survive.
What is binomial nomenclature and why is it important?
Two-word Latin scientific name given to each species (genus-species) for the purpose of having a universal
language among scientists. Genus
species example: Homo sapiens (Human species) (Genus is upper-cased and species is lower-cased) (both
are italicize
List the 7 taxonomic categories from the largest to the smallest groups.
Kingdom, phylum, class, order, family, genus, species
(King Philip came over for good spaghetti)
What do scientists believe the age of the earth is?
4.6 billion years old
What was the old name for the kingdom of bacteria?
Monerans
What is Eubacteria (Bacteria)?
The domain with the true bacteria (cell walls with peptidoglycan)
What is Archaea (Archaebacteria)?
The domain with (live in extreme
environments) (no peptidoglycan).
What is Eukarya?
The domain of organisms called eukaryotes (have nuclei).