Option D

Luis Zavala, Katie and Lucy, Kaila and Mac, Michael, Davis

D.1.1 - Luis• the non-living synthesis of simple organic

molecules• the assembly of these molecules into

polymers• the origin of self-replicating molecules that

made inheritance possible• the packaging of these molecules into

membranes with an internal chemistry different from their surroundings.

D.1.2The Miller-Urey experiment simulated the

hypothetic conditions of early Earth and tested the occurance of chemical evolution. The experiment used water, methane, ammonia, and hydrogen gas. Electrical discharges and boiling and condensing water simulated lightning and rainfall.  The system yielded carbon in organic compounds, 15 amino acids, sugars, lipids, and some of the building blocks of nucleic acids.

D.1.3Comets contain a variety of organic

compounds. Heavy bombardment about 4,000 million years ago may have delivered both organic compounds and water to the early Earth.

D.1.4Examples should include communities around deep-sea

hydrothermal vents, volcanoes and extraterrestrial locations.·         Deep sea vents: ammonia and methane are present, and

were not present elsewhere in the early atmosphere. There are many organisms currently living around deep sea vents suggesting this is a possible explanation.

·         Volcanoes: volcanic eruptions involve the release of methane, ammonia, and hydrogen gases as well as water vapor. This, when combined with lightning, creates a real-life version of the Miller-Urey experiment.

·         Extraterrestrial locations: Comets contain a variety of organic compounds. Heavy bombardment may have delivered both organic compounds and water to the early Earth.

D.1.5RNA is able to store genetic information, like

DNA, and catalyze chemical reactions; therefore it is believed that RNA alone could have supported pre-cellular life.

D.1.6RNA is able to store genetic information, like

DNA, and catalyze chemical reactions; therefore it is believed that RNA alone could have supported pre-cellular life.

D.1.7Some bacteria can produce oxygen

Cyan bacteriaContributed to oxygen rich atmosphere

D.1.8Both mitochondria and chloroplasts

descended from engulfed bacteria, through the process of endocytosis,  and over time have evolved from independent prokaryotic cells.

Part D.2 – Lucy and Katie

  Define allele frequency and

gene pool Allele frequency: the proportion of

all copies of a gene that is made up of a particular gene variant (allele)

Gene pool: The stock of different genes in an interbreeding population.

D2.2 State that evolution involves a change in allele frequency in a population’s gene pool over a number of generations

Evolution involves a change in allele frequency in a population’s gene pool over a number of generations

D2 D2.3 Discuss the definition of the term species -         Biological species concept: to be part of the

same species the organisms must be able to actually or potentially interbreed in nature. A species is the largest gene pool possible in nature. Cannot be applied to bacteria and other organisms that reproduce asexually. What about geographical boundaries? What about hybrids?

D2.4 Describe three examples of barriers between gene pools

-         Examples include geographical isolation, hybrid infertility, temporal isolation and behavioural isolation.

D2 D2.5 Explain how polyploidy can contribute to

speciation -         Polyploidy: cells contain 3 or more sets of chromosomes

(3n, 4n, etc.) -         Plants (that are both male and female and therefore can

fertilize themselves) and other asexual organisms do this and reproduce offspring that are different from existing species.

D2.6 Compare allopatric and sympatric speciation -         Speciation: the formation of a new species by splitting

of an existing species. -         Sympatric: in the same geographical area. -         Allopatric: in different geographical areas

Analogous Structures

D2.7 Outline the process of adaptive radiation

-         Adaptive radiation: similar but distinct species evolve relatively rapidly from a single species or from a small number of species. Variation in a species results in some members of the population being more suited to a different niche. Example: Galapagos finches

D2.8 Compare convergent and divergent evolution

-         Convergent evolution: species become more similar over time (analogous traits)

-         Divergent evolution: species become less and less similar over time (homologous traits)

D2.9 Discuss ideas on the pace of evolution, including gradualism and punctuated equilibrium

-         Gradualism is the slow change from one form to another. Punctuated equilibrium implies long periods without appreciable change and short periods of rapid evolution

D2 D2.10 Describe one example of

transient polymorphism -         Transient polymorphism: one form

is gradually being replaced by another. As the name implies, it represents a temporary situation.

-         Example: Industrial melanism- During  Industrialization in England, dark-colored (melanic) peppered moths gradually predominated the light-colored (non-melanic) form due to selective pecking of the latter by the birds.

D2.11 Describe sickle-cell anemia as an example of balanced polymorphism

-         Sickle-cell anemia is an example of balanced polymorphism where heterozygotes (sickle-cell trait) have an advantage in malarial regions because they are fitter than either homozygote.

Part D3 – Mac and Kaila

D.3.6 State that, at various stages in hominid evolution, several species may have coexistedThere are several examples of overlapping stages of hominid evolution, including:•H. neanderthalenisis and H. sapiens•H. erectus (China) and H. erectus (SE Asia)•P. robustus and P. baisei•H. habilis and H. rudolfensis•A. africanus and A. gethiopicus•H. neanderthalenisis and H. erectus (China)•H. neanderthalenisis and H. erectus (SE Asia)•Etc.

•The coexistence of a hominid species is determined by the individuals found millions of years ago (mya) together, aka the heads that are found within the my coexisted

Source: http://www.accessexcellence.org/BF/bf02/klein/slides/PhyloftheHom.gif

D.3.7 Discuss the incompleteness of the fossil record and the resulting uncertainties about human evolutionThere are several missing links within the fossil record as well as not exact but general time periods for certain species. These missing links do not allow scientists to make conclusions but instead speculations. Missing links include between:•A. africanus and A. afarensis•H. ergasta and H. habilis•The Homo genus and the Parenthropus genus•K. platyops and A. ranidus •A. anaemeniss and A. ramidus•There are also missing links between the first humanoid fossils found, O tugensis, and more modern/relatable fossils, H. neanderthalensis

The lack of evidence prevents conclusions and so leads to uncertainties about human evolution.

Source: http://www.accuracyingenesis.com/hhtree.gif

D.3.8 Discuss the correlation between the change in diet and increase in brain size during hominid evolution

Source: http://evolution-textbook.org/content/free/figures/25_EVOW_Art/11_EVOW_CH25.jpg

The skull and brain have increased as hominids have developed.

Larger brains have benefits such as increased awareness and brain function allowing for minds to become more developed.

With this development of the brain came a change in diet, in which hominids changed their diet from a largely fruit and vegetable diet to a diet containing larger amounts of meat (protein). The larger the hominid brain, the more energy needed and so hominids needed a more long term and sustainable energy source, which they found in proteins and fats which created longer lasting energy for function then fruits and vegetables.

D.3.9 Distinguish between genetic and cultural evolution

Genetic Evolution• the change that occurred during the

evolution of the hominids, changes that are related to both the phenotype and genotype of the hominid species

• Examples: increase in brain and skull size, bipedalism, curvature of the spine, etc.

Cultural Evolution• the change that occurred during the

evolution of the hominids, changes that are related to both the phenotype and genotype of the hominid species

• Examples: beliefs about gods, agriculture, traditions (Cinco de Mayo, Fourth of July), ideas and methods about marriage and beauty, etc.

Source: http://www.charlesayoub.com/news/public/uploads/images/45871101692318920.png

Genetic Evolution

Cultural EvolutionAfrican Idea of BeautySource: http://nicefun.net/userpix5/AfricanBeauty_NiceFun_17_1203.jpg

Indian Idea of BeautySource: http://2.bp.blogspot.com/-uJy2tyOiQ4Q/T2pJVZX9LiI/AAAAAAAAE9Y/gerGEdevi8M/s1600/d08_indian_bride.jpg

D.3.10 Discuss the relative importance of genetic and cultural evolution in recent

evolution of humans

D4 – Hardy Weinberg - Michael

• Definition:• The Hardy-Weinberg Equilibrium Equation is an

equation that represents, given data about two alleles, the number of each allele in a given population. It makes several assumptions:

• 1. Random Breeding • 2. No natural selection • 3. No immigration or emigration • 4. No genetic drift

Derivation of Hardy-Weinberg

Consider two alleles A and a

A has a frequency of pa has a frequency of q Therefore p + q = 1

As the two alleles are the only options at that locus

Lets make a Punnet square:

http://en.wikipedia.org/wiki/Hardy%E2%80%93Weinberg_principle

D5 – Davis Berlind.

D.3.1 Outline the method for dating rocks and fossils using radioisotopes with reference to 14 Cand 40 K (2)

All living things contain carbon and once that organism dies it stops taking in carbon and the carbon within the system, 14 C, begins to decay.  Scientists measure the amount of carbon within the system as compared to the living organism to determine how long ago it died. 14C is used to measure the age of animal/living organisms, and 40K  is used to discern the age of lava and sedimentary rock. 40 K is found in lava when a lava is released, but as lava/rock ages the amount of 40K in the system reduces and the amount of 40Ar increases (since when the lava is released the 40K: 40Ar ratio is 100:0), telling scientists the age of the rock/lava.

D.3.2 Define half-life (1) The time it takes for half of the radioactive isotope to decay.

D.3.3 Deduce the approximate age of materials based on a simple decay curve for a radioisotope (3)

http://phet.colorado.edu/en/simulation/radioactive-dating-game D.3.4 Describe the major anatomical features that define

humans as primates (2) Humans are defined as primates because of their grasping pentadactyl

limbs, binocular vision, reduced snout leading to reduced olfaction, generalized dentures, forelimbs that can twist, slower reproduction with usually one offspring at a time and longer gestation, larger skull (relative to body sixe) with a larger brain, better visual acuity, social dependency and a clavicle that allows a wider range of arm movement.

D.3.5 Outline the trends illustrated by the fossils of Ardipithecus ramidus, Australopithecus including A. adarensis and A. africanus, and Homo including H. habilis, H. erectus, H. neanderthalenisis and H. sapiens (2)

The different structures of the fossils shows the trends of the enlargement of the skull through the ages to allow for the growth of the brain, shortening of the face and the loss of brow ridges. Furthermore, the foram magnum is further forward in later fossils so as to balance the body’s structure and reduce the need for larger necks muscles. The fossils also show a development in the jaw from a U shape to more of a V shape, as well as, development of the hands and feet for different functions including manipulation and grasping and running/walking in an upright position. Furthermore, the skeletal structures of later fossils show greater change including the alignment of the knees under the body’s center of gravity, straightened legs for walking, curved spines for more mobility and better balance, the loss of an opposable big toe and an arch in the foot. Also the legs to arms ratio allow more mobility and balance as well as a broader pelvis for later fossils for bipedalism and reproduction.

D5.3: phylogeny is the evolutionary history of a (taxonomic) group, and differences between molecules can be used to deduce phylogeny. Because mutation rates in DNA occur at predictable rates, we can compare nucleotide sequences of DNA and aminor acid sequences of proteins between taxa and use the differences (mutations) as “molecular clock” for evolution. If DNA/amino acid sequences are close enough, we can deduce phylogeny/common ancestry use the rate of mutation to predict how long ago a common ancestor was shared. However, mutations are chance events so caution must be taken when interpreting this kind of data. Additionally, globin genes (e.g. those that code for hemoglobin and myoglobin) can be used to indicate phylogeny. Globin genes are present in all animals and some plants. The greater the similarity in the globin genes of two species, the less time has passed during which mutations could accumulate, and thus, the degree of similarity can be used as a measure of how closely related the two species are. The greater the similarity in a protein produced by two species, the more recently they shared a common ancestor.

D5.4: Differences in nucleotide base sequences in DNA, and therefore amino acid sequences in proteins, accumulate gradually over long periods of time. Because these differences accumulate at roughly constant and predictable rate, the number of differences can be used as a clock to measure the time since two divergent groups shared a common ancestor. One protein commonly used for this method is hemoglobin, a blood protein found in all vertebrates. Changes in the amino acid sequence of hemoglobin can be used to date divergence with a common ancestor.

D5.5: ·   Clade: a group of organisms that evolved

from a common ancestor ·   Cladistics: a method of classification of

living organisms based on the construction and analysis of cladograms

·   Nodes: branch points indicating the evolution of shared derived characteristics

D5.6: Analogous structures function similarly in the organisms that posses them but have different evolutionary origins. For example, the wings of moths and birds are analogous. Homologous structures have a common evolutionary origin, though they often have different functions, an example being the dolphin fin and human arm.

D5.7: First, the set of data is arranged to compare the relevant taxa being examined. The outgroup is isolated by identifying the taxa with the primitive condition for the characters being examined. Next, the branches of the phylogenic tree are determined by comparing the number of derived characters in each taxon, with each nod on the tree representing an ancestor common to all species above that node. The nodes also represent a change in an ancestor from the primitive to the derived character state (shared derived characters are called synapomophies). The tree should follow the parsimony principle, that the simplest tree that is consistent with the comparative data is most likely the correct one. From cladograms we can determine the evolutionary path of an animal and conclude when certain traits arose.

D5.10: cladograms (often) confirm existing classifications since both are based on phylogeny. Cladograms are (sometimes) different than traditional classifications, because nodes can be placed at any point / arbitrary. cladograms (sometimes) radically alter existing classifications, for example, birds are grouped with dinosaurs despite differing class. The strength of cladistics is that the comparisons are objective because rely on molecular homologies. However, such molecular differences are based on probabilities and therefore can be unreliable.

THE END.