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GENBIO Recombinant DNA may be created through transformation with the help of a vector, such as bacterial cells. Vectors Genetic Engineering...

GENBIO Recombinant DNA may be created through transformation with the help of a vector, such as bacterial cells. Vectors Genetic Engineering are organisms that are normally harmless is a process of making changes on the but may help spread infection by genetic code of an organism. Its goal is transferring the genetic material from one to add one or more new traits that are host to another. In the transformation not normally found in that organism. process, a selected portion of the Through advanced studies in the foreign DNA is inserted into a small, structure of DNA and its chemical circular DNA molecule called plasmid, properties, scientists have been able to which is naturally found in bacteria. employ different techniques to extract, Plasmids are the most useful tool in gene cut, and make unlimited copies of DNA. transformation for two reasons. First, a the alteration of an organism’s plasmid contains a gene sequence that genotype using recombinant DNA technology to modify an organism’s serves as a bacterial origin of DNA to achieve desirable traits. replication. This is where the foreign DNA can be inserted into the bacterial DNA recombination cell. Second, it also contains a genetic is a process of modifying the genes of marker, which makes it possible to organisms for practical purposes. It is distinguish bacteria that carry the done when a piece of DNA is plasmid-containing foreign DNA. Some combined with another DNA from of these genetic markers code for another source. The resulting genetic antibiotic resistance. product is called recombinant DNA. During transformation, a restriction With this process, organisms get to endonuclease enzyme is used to cut the have traits that are not normally found piece of the donor DNA. This enzyme in their species. cleaves the DNA at the phosphate-sugar bond, and thus sticky ends are created. Sticky ends are areas in the DNA where Processes Used in Recombinant DNA the bases are ready to be paired. Technology Restriction enzymes cut the DNA only There are three methods by recombinant at a specific nucleotide sequence. They DNA is made. These are transformation, work precisely like a key that fits only one vector less gene transfer, and specific lock. Then, an enzyme known transduction. as DNA ligase is used to insert the donor DNA into the vector. It seals the sticky ends by joining the phosphate and 1) Transformation Using a Vector the sugar bonds in the DNA. The inserted DNA also contains a genetic marker for identification. The recombinant DNA is then inserted into a bacterial cell, such as E. coli. After transformation, the culture is treated with an antibiotic. Those that have been transformed will be the only ones to survive because they carry the resistance gene. 2.2) In protoplast fusion, cells are treated with chemicals to initiate recombination. In this process, bacterial cell walls are digested, turning the cells into protoplasts. These protoplasts are treated with polyethylene glycol to allow them to fuse, creating a random recombination of genes. The resulting recombinant cell will now grow a new cell wall. 2) Vectorless Gene Transfer This process is similar to transformation, but it does not involve vectors. The types of vectorless gene transfer include electroporation, protoplast fusion, microinjection, and use of a particle gun. 2.1) In electroporation, temporary holes are formed in the plasma membrane of 2.3) In microinjection, the host cell is the host cell by applying a significant immobilized by applying a mild suction amount of electricity in the culture with a blunt pipette. The foreign gene is medium. This enables the entry of foreign then injected with a microinjection DNA via the pores. needle, thus creating recombinant DNA. 2.4) In using a particle gun for recombination, the host cell is bombarded with tungsten particles coated with foreign DNA. This process is used in the field of agriculture. Many farmers use this method to genetically modify plants to make them highly resistant to insects and other pests. Some also use this method to develop crops that can survive extreme weather conditions. Figure 5 shows the comparison between the use of vectors and the particle gun method. CLASSICAL BREEDING/ARTIFICIAL SELECTION ✓ mating of organisms with desirable qualities ✓ does not involve any direct manipulation of genetic material. ✓ (Non-Genetically Modified Organisms) ✓ breeders choose which organism to 3) Transduction mate to produce offspring with desired traits. Transduction is the process wherein ✓ They cannot control what genes are genetically engineered bacteriophages- passed. viruses that parasitize bacteria- are ✓ When they get offspring with the introduced into the cell to create the desired traits, they maintain them. desired recombinant DNA. The steps involved in transduction are shown in figure 6. SELECTIVE BREEDING A. hybridization B. inbreeding Luther Burbank ✓ when animals/plants with desired characteristics are mated to produce Example:In the late 1800s Luther offspring with those desired traits. Burbank created a disease resistant ✓ Passing of important genes to next potato called the Burbank potato. generation. He crossed a disease resistant plant with one that had a large food producing capacity. Process of Selective Breeding Result: disease resistant plant that makes a lot of potatoes. Selective breeding occurs when you choose the best male and female to breed. Other Examples This allows you to fine tune and control the traits 1. Liger: lion and tiger mix The offspring or babies will then have the best traits. Then you continue to breed those organism with the best traits, those traits will be maintained. 2. Grape + apple= grapple. The fruit tastes like grapes and looks like apple. A. Hybridizations: two organisms with unlike characteristics are crossed to produce the best in both organisms. Hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Advantages ✓ passing along favorable traits ✓ prolonging the survival of a threatened or endangered species Disadvantage  ✓ Genetic swamping due to its Some finches have short beaks, some have long disruptive effects on genetic beaks. integrity of species and potential to eliminate unique Classical breeding has been used to create many adaptations. of the things familiar to life today: ✓ hybrid animals have more ✓ ✔ modern agriculture difficulty finding mates and ✓ ✔ domesticated plants and animals successfully breeding. ✓ ✔ all cat and dog breeds ✓ ✔ many of the existing commonly used industrial yeast strains. B. Inbreeding The addition of foreign DNA in the form of recombinant DNA vectors generated ✓ breeding of organism that genetically by molecular cloning is the most similar to maintain desired traits. common method of genetic ✓ Dog breeds are kept pure this way. engineering. ✓ It’s how a Doberman remains a The organism that receives the Doberman. recombinant DNA is called a genetically ✓ It keeps each breed unique from others. modified organism (GMO). If the foreign DNA that is introduced comes from a different species, the host Advantages: organism is called transgenic. ✓ Inbreeding is done to develop pure lines. ✓ It increases the homozygosity and helps in the accumulation of superior genes. ✓ Inbreeding also helps in eliminating less desirable genes. Disadvantages: ✓ since both have the same genes, the chance that a baby will get a recessive GENETICS: INTRO TO DNA genetic disorder is high. - DNA stores the genetic code for all ✓ blindness, joint deformities. living things. ✓ Inbreeding decreases variations. - DNA is made of tiny building blocks called "nucleotides," which connect to each other to make long chains. Variation: difference between individuals of a - Each DNA molecule contains a special species. sugar inside it called "deoxyribose." For example: Some humans have blond hair DNA SHAPE and some have brown. This is a variation ✓ Each DNA strand contains two among humans. nucleotide chains coiled around  each other to form a double helix Flavr Savr (also known as CGN-89564-2; shape. pronounced "flavor saver"), a genetically modified tomato, was the first commercially The ‘code’ on each strand of DNA is made grown genetically engineered food to be up of four different nucleotides. granted a license for human consumption. It Adenine (A) was developed by the Californian company Cytosine (C) Calgene in the 1980s. Guanine (G) Thymine (T) Recombinant DNA technology is the joining together of DNA molecules from two different ✓ A DNA sequence is read in groups of species. The recombined DNA molecule is three letters. inserted into a host organism to produce new ✓ These triplets are called codons, and genetic combinations that are of value to each codon codes for a specific amino science, medicine, agriculture, and industry. acid. ✓ Amino acids are the building blocks of The first recombinant DNA (rDNA) molecules proteins. were generated in 1973 by Paul Berg, Herbert ✓ Proteins perform many jobs in our body, Boyer, Annie Chang, and Stanley Cohen of from helping you digest food to making Stanford University and University of California your muscles move. San Francisco. In 1975, during “The Asilomar Conference” regulation and safe use of rDNA technology was discussed WHAT ABOUT GENES? The steps in recombinant DNA technology Genes are segments of your DNA. include: 1. isolating DNA from the donor Genes are made up of many codons - and host organisms, just like sentences make up paragraphs 2. cutting the DNA using and paragraphs make up chapters in a restriction enzymes, book. 3. joining the fragments with DNA ligase, 4. introducing the recombinant DNA into the host organism, 5. and selecting and screening transformed cells. Genomics is the study of entire genomes, including the complete set of genes, their nucleotide sequence and organization, and their interactions within a species and with other species. Genome is the genetic material of an organism. It consists of DNA (or RNA in RNA viruses). The genome includes both the genes (the coding regions) and the noncoding DNA, as well as the word "bacteriophage" literally means mitochondrial DNA and chloroplast DNA. "bacteria eater," because bacteriophages destroy their host cells. Chromosomes are thread-like structures located all bacteriophages are composed of a nucleic inside the nucleus of animal and plant cells. acid molecule that is surrounded by a protein Each chromosome is made of protein and a structure. single molecule of deoxyribonucleic acid (DNA). Plasmid A gene is the basic physical and functional unit is a small, extrachromosomal DNA molecule of heredity. Genes are made up of DNA. Some within a cell that is physically separated from genes act as instructions to make molecules chromosomal DNA and can replicate called proteins. However, many genes do not independently. code for proteins. In humans, genes vary in size They are most commonly found as small from a few hundred DNA bases to more than 2 circular, double-stranded DNA molecules in million bases bacteria. Deoxyribonucleic acid (DNA) is a molecule Cosmids composed of two polynucleotide chains that coil These are vectors possessing the characteristics around each other to form a double helix of both plasmid & bacteriophages. carrying genetic instructions for the designed to clone large fragments of DNA and development, functioning, growth and to grow their DNA as a virus or as a plasmid reproduction of all known organisms. In vivo 46 CHROMOSOMES In vivo is Latin for “within the living.” It refers to work that’s performed in a whole, living In each chromosome, therefore in each DNA organism. molecule, there are hundreds to thousands of genes In vitro In vitro is Latin for “within the glass.” When Transgenic Organism something is performed in vitro, it happens If the foreign DNA that is introduced comes outside of a living organism from a different species, the host organism is called transgenic. Molecular Cloning a set of experimental methods in molecular Vector biology that are used to assemble recombinant In molecular biology, a vector is a DNA molecule DNA molecules and to direct their replication used as a vehicle to transfer foreign genetic within host organisms. material into another cell. Polymerase Chain Reaction Bacteriophage A technique in molecular biology for creating also known informally as a phage, is a virus that multiple copies of DNA from a sample infects and replicates within bacteria and Restriction Enzyme (“Molecular Scissors”) archaea. An endonuclease that catalyzes double-strand cleavage of DNA containing a specific sequence  coated pellets and acquire the ability to Ligases express the designed protein. are enzymes that join the nucleic acid molecules Other terms for Biolistic are: together. Particle Bombardment These nucleic acids can either be DNA or RNA, Microprojectile bombardment and the enzymes are thus called DNA ligase and Particle acceleration RNA ligase, respectively Particle inflow gun Gene gun Polymerases DNA polymerases are enzymes that catalase the 2.Plasmid insertion by Heat Shock Treatment synthesis of a new DNA strand from a pre- ✓ Heat Shock Treatment is a process used existing strand to transfer plasmid DNA into bacteria. ✓ The target cells are pre-treated before the procedure to increase the pore sizes A general outline of recombinant DNA may be of their plasma membranes. given as follows: ✓ This pretreatment (usually with CaCl2) is I. Identification and Isolation of the Gene said to make the cells “competent” for of interest or DNA fragment to be accepting the plasmid DNA. cloned ✓ After the cells are made competent, II. Insertion of this isolated gene in a they are incubated with the desired suitable vector plasmid at about 4°C for about 30min. III. Introduction of this vector ✓ The plasmids concentrate near the cells into a suitable during this time. organism/cell called host ✓ Afterwards, a “Heat Shock” is done on IV. Selection of the transformed host cell the plasmid- cell solution by incubating V. Multiplication or expression of the it at 42°C for 1 minute then back to 4°C introduced gene in the host. for 2 minutes. ✓ The rapid rise and drop of temperature Ways In Which These Plasmids May Be is believed to increase and decrease the Introduced into Host Organisms. pore sizes in the membrane. ✓ The plasmid DNA near the membrane 1.Biolistics surface are taken into the cells by this ✓ In this technique, a “gene gun” is used process. to fire DNA- coated pellets on plant ✓ The cells that took up the plasmids tissues or directly shoots a piece of DNA acquire new traits and are said to be into the recipient plant tissue. “transformed”. ✓ Tungsten or gold beads are coated in the gene of interest and fired through a stopping screen, accelerated by Helium, 3.Electroporation into the plant tissue. The particles pass through the plant cells, leaving the DNA ✓ This technique follows a similar inside. methodology as Heat Shock Treatment, ✓ Cells that survive the bombardment are but, the expansion of the membrane able to take up the expression plasmid  pores is done through an electric “shock”. ✓ This method is commonly used for insertion of genes into mammalian cells. History of Life on Earth ✓ Geologists have divided Earth's history into a series of time intervals. ✓ These time intervals are not equal in length like the hours in a day. ✓ Instead, the time intervals are variable in length. PRECAMBRIAN ✓ This is because geologic time is divided HADEAN EON (4.6- 4 BILLION YEARS AGO) using significant events in the history of the Earth. At the start of the Hadean, the solar system was still forming within it's accretion disc and the planet was subjected to millions of years of violent impacts known as the Late Heavy Bombardment. Although many scientists contend that the atmosphere and the oceans formed during the latter part of the eon, the discovery of the zircon grains in Australia provide compelling evidence that the atmosphere and ocean formed before 4.4 billion years ago. As you might imagine, NO LIFE could have survived the Hadean Era. Even if there were living things back then, they The sequential time arrangement would all have been destroyed by the or settings, of the earth history heat caused by comet and asteroid impacts. ARCHEAN EON (4.0- 2.5 BILLION YEARS AGO) in the ARCHEAN EON, Earth finally starts to cool down with a more stable climate. OCEANS AND CONTINENTS: Because Earth cooled down, it was able to support oceans and continents.  OZONE LAYER: Eventually, the ozone PROTEROZOIC EON (2.5 BILLION YEARS AGO- layer forms. This layer of protection 541 MILLION YEARS AGO) was essential for life to form. 1. Great Oxygenation Event It was early in the Archean that life Evolutionary advancements in first appeared on Earth. Our oldest multicellular cyanobacteria completely fossils date to roughly 3.5 billion years transformed the atmosphere by adding ago, and consist of bacteria free oxygen gas (O2) and causing the microfossils. decimation of the anaerobic (non- Fossils of stromatolites, which oxygen) bacteria that existed at the were instrumental in creating the free time. oxygen in the atmosphere are found Oxygenation of the atmosphere is throughout the Archean, becoming the single biggest event that especially common late in the eon. distinguishes the Archean Earth and ▪ Stromatolites, also known as layered the Proterozoic Earth rocks, form in shallow waters when Free oxygen reacted with methane in biofilms of living microorganisms, like the atmosphere, turning it into carbon cyanobacteria, trap sediment. Most dioxide. Methane is a more effective stromatolites grow in extremely salty greenhouse gas than carbon dioxide, lagoons or bays, in places like Australia, and as CO2 increased in the Brazil, Mexico and the Bahamas atmosphere, the greenhouse effect ▪ Microbial mats are complex actually decreased, thus cooling the communities of microbes, usually planet. organized into layers that can be seen 2. Snowball Earth with the naked eye. They were one Snowball Earth hypothesis proposes of the earliest ecosystems on Earth that during one or more of Earth's BANDED IRON FORMATIONS: Next, icehouse climates, Earth's surface oxygen filled the oceans from became entirely or nearly entirely cyanobacteria. Interestingly, most of frozen(-50°C)/ (-74°F), sometime earlier the world’s iron ore deposits were than 650 Mya (million years ago) during produced in this eon from banded the Proterozoic Eon. iron formation. 3. Symbiotic Relationships ▪ A nearly 3-billion-year-old banded iron formation from Canada shows It was also during the Proterozoic that that the atmosphere and ocean once the first symbiotic relationships had no oxygen. Photosynthetic between mitochondria (for nearly all organisms were making oxygen, but it eukaryotes) and chloroplasts (for plants reacted with the iron dissolved in and some protists only) and their hosts seawater to form iron oxide minerals on evolved. the ocean floor, creating banded iron 4. Sexual Reproduction by some formations. Eukaryotes By sharing genetic material between reproducing individuals (male and female), evolutionary change was enhanced by increasing genetic variability. This allowed more  complexity among individual organisms, to piece together a pretty good and eventually, ecosystems. evolutionary story. 5. Proterozoic rocks contain many definite ✓ The diverse fossils also provide traces of primitive life-forms—the fossil geologists with very fine time remains of bacteria and blue-green resolution. algae, as well as of the first oxygen- PALEOZOIC ERA (541-251 MILLION YEARS AGO) dependent animals, the EDIACARA OLD LIFE FAUNA. ✓ the first and the longest era of the Fauna - the animals of a particular region, Phanerozoic, habitat, or geological period. ✓ noted by the emergence of diverse animal and plant life, as well as significant climate and geological Ediacaran biota is a taxonomic period change. classification that consists of all life forms that were present on Earth during the Ediacaran Period (ca. 635–542 Mya). CAMBRIAN PERIOD (541-488 MYA) CAMBRIAN These were composed of enigmatic tubular EXPLOSION and frond- shaped, mostly sessile, ✓ characterized by trilobites, the first four- organisms. Trace fossils of these organisms limbed vertebrates, and the origin of have been found worldwide, and represent land plants. the earliest known complex multicellular ✓ During this time, the Earth's landmass organisms. was broken up into a substantial number of relatively small continents. Proterozoic is distinct from Archean in: ❖ Clear evidence of "modern-style" (continent-scale) plate tectonics ❖ HUGE deposits of Banded Iron Formations during the 1st half of Paleoproterozoic ❖ Complex unicellular, and first multicellular life ❖ Indications of higher levels of oxygen ▪ Trilobites are a group of extinct marine artiopodan arthropods that form the class Trilobita. Trilobites form one of the PHANEROZOIC EON (541 MILLION YEARS AGO- earliest-known groups of arthropods. PRESENT TIME) THE EON OF VISIBLE LIFE ✓ Most major groups of animals appeared ✓ This eon is the most critical one as far as in the fossil record during this period. life is concerned for several reasons. This event is known as the Cambrian ✓ There is an abundant fossil record in the explosion, because of the short Phanerozoic, one that allows geologists amount of time in which this  diversity appeared - just 40 million ✓ Plants also began to colonize land, years. originating with freshwater algae that adapted to life in drying pools. ✓ Mass Extinction ✓ Life On Land The Cambrian Period began with an Mosses and other primitive plants grew explosion of life forms. It ended in a over the land near the water’s edge. mass extinction. Advancing glaciers They continued the work of the lichen would have lowered the temperature turning the rock into soil. There are a of the shallow seas where so many few fossils from the end of the Silurian species lived. Changes in the Period that show us early insects lived temperature and the amount of oxygen among these mosses and made their in the water would have meant the own colonies. end for any species that could not ✓ It is marked by the evolutionary adapt. radiation of fish, hence its nickname, the age of fish. ✓ The first trees would appear toward the ORDOVICIAN PERIOD (488-444 MYA) end of the period. ✓ The ancestors of tetrapods, four-legged ✓ a rich variety of marine life flourished in vertebrates, began adapting to walking the vast seas and the first primitive on land. plants began to appear on land ✓ These first steps toward life on land LATE DEVONIAN EXTINCTION (372 MYA) were cut short by the freezing ✓ An extinction event occurred during the conditions that gripped the planet end of the Devonian period, affecting toward the end of the Ordovician. jawless fish, trilobites, ammonites, and more. The causes of this event are still unknown. ORDOVICIAN-SILURIAN EXTINCTION (455-430 MYA) ✓ Glaciers forming on Gondwana, a CARBONIFERIOUS PERIOD (359- 299 MYA) supercontinent settled over the south ✓ The Carboniferous is the fifth period of pole, would cause a change in sea level, the Paleozoic, named for the coal and begin an ice age. deposits that formed due to its swamps. ✓ This change resulted in an extinction ✓ In the US, it can be further split into the event that devastated marine Mississippian and the Pennsylvanian.. environments, eliminating nearly 85% ✓ Seed plants appeared during this of marine species. period, and animals would continue to evolve on land, including tetrapod and amphibian SILURIAN PERIOD (444-416 MYA) ✓ Reptiles appear for the first time ✓ The animal world rebounded from the extinctions for most of the period. CARBONIFEROUS RAINFOREST COLLAPSE (305 what is now Siberia led to a huge MYA) outpouring of lava. ✓ Global climate change caused the MESOZOIC ERA (252-65 MYA) collapse of the world’s rainforests. It is also called the Age of Reptiles, as they and ✓ This caused some amphibian species to other sauropsids were the dominant animals at go extinct as their habitats shrunk and the time. changed. ✓ Reptiles fared better, thanks to Dinosaurs are the most famous creatures from adaptations that allow them to survive this era, but mammals, pterosaurs, and in drier habitats. flowering plants would appear as well. PERMIAN PERIOD (299-252 MYA) ✓ The Permian is the last of the Paleozoic periods. ✓ Reptiles would rise to dominance in the dry climates of the supercontinent Pangaea. ✓ Amphibians would decline, but not disappear entirely. ✓ The ancestors of mammals, turtles, Sauropsids are the sister taxon to synapsids— lizards, and archosaurs (like birds and also referred to as "mammal-like reptiles," crocodiles) would all appear during this although synapsids are not part of the class period. reptilia— some of which later evolved into mammals. GREAT PERMIAN EXTINCTION (252 MYA) Pterosaurs were flying reptiles of ✓ The end of the Paleozoic era is marked the extinct clade by a massive extinction event known as or order the Permian- Triassic extinction, or the Pterosauria. They Great Dying. existed during ✓ 95% of marine life, and 75% of most of the terrestrial life, died out due to volcanic Mesozoic. eruptions poisoning the atmosphere. ✓ It is the largest extinction event in Earth’s history. TRIASSIC PERIOD (252-200 MYA) ✓ Warming of the Earth's climate and associated changes to oceans were the ✓ The Triassic is the first period of the most likely causes of the extinctions. Mesozoic. ✓ At the end of the Permian Period ✓ The climate in Pangaea was very dry, volcanic activity on a massive scale in especially at its interior.  ✓ Therapsids and archosaurs managed to Pangaea had broken up toward the end of the thrive in these conditions, and despite Triassic, and the climates changed, becoming the massive extinction. cooler and more humid. ✓ Dinosaurs first appeared during this Insects became part of plant reproduction by time, as did frogs, true mammals, and transporting pollen during this period, and the gingko trees. first birds appeared. Therapsids (mammal-like reptiles) were the CRETACEOUS PERIOD (145-66 MYA) stock that gave rise to mammals. ✓ The Cretaceous is the third, and last, period of the Mesozoic. ✓ Flowering plants appeared at the start of this period. ✓ Dinosaurs reached the height of diversification ✓ Birds, crocodiles, and mammals continued to develop. ✓ By the end of the period, the continents were roughly in the places they sit today. Archosaur, any of a reptile lineage, including ✓ Some of the largest dinosaurs, all crocodiles and birds, as well as dinosaurs pterosaurs, and crocodylomorphs lived and pterosaurs, that emerged during the Triassic during this period. Period. CRETACEOUS- PALEOGENE EXTINCTION (66-65 TRIASSIC – JURASSIC EXTINCTION (201 MYA) MYA) ✓ marks the boundary between the ✓ The K- Triassic and Jurassic periods Pg event is ✓ 34% of marine genera went extinct, one of the including an entire class of jawless fish. most ✓ Many archosaurs, therapsids, and large famous amphibians also went extinct. mass ✓ The extinctions at the end of the Triassic extinctions. were initially attributed to gradually It is thought that the event was caused changing environments. by a massive asteroid impact. 75% of all species on earth went extinct. ✓ Non-avian dinosaurs, pterosaurs, JURASSIC PERIOD (200-145 MYA) plesiosaurs, mosasaurs, and ammonites Dinosaurs would flourish in the wake of the disappeared completely, and many extinction, and become the dominant animals. other groups saw massive losses. CENOZOIC ERA (66 MYA-PRESENT)  ✓ The Cenozoic is the current geological Miocene epoch when horses and tigers era, ongoing today. dominate the land ✓ In the wake of the K-Pg event, birds and Pliocene epoch when hominids or the bipedal mammals began to fill the niches left apes develop. empty by the dinosaurs. ✓ The era became known the Age of Mammals, due to the dominance and diversity of the latter. QUATERNARY PERIOD (2 MYA-PRESENT) ✓ Mammalian megafauna and the rise of ✓ The Quaternary is the third, and humans are hallmarks of this era. current, period of the Cenozoic. ✓ The period is marked by an ongoing ice age and various glaciations. PALEOGENE PERIOD (66-23 MYA) ✓ Giant mammals lived during the last glaciation period, and modern humans ✓ The Paleogene is first period of the developed within the last 315,000 Cenozoic. years. ✓ The world became more recognizable as the continents continued to move toward their present-day positions. ✓ Mammals diversified widely, and plants Pleistocene epoch is recovered from the changes in climate. when modern humans ✓ Many fish and reptiles would gain develop, Pleistocene recognizable forms. epoch is also the ice age because ice sheets Paleocene epoch when the first horse appear, predominate during this epoch. Eocene epoch when grasses spread and large mammals such as elephants and rhinos Holocene epoch where humans flourish and developed dominate the earth. Oligocene epoch when dogs, cats, and apes ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ appear, As you can deduct from the discussed geologic time scale: we are currently living in the Phanerozoic eon, Cenozoic era, Quaternary NEOGENE PERIOD (23-2 MYA) period, and Holocene epoch. ✓ The Neogene is the second period of the Cenozoic. ✓ Birds and mammals began to adopt FOSSILS familiar, modern forms. ✓ North and South America were ✓ More than 90 percent of all organisms connected by the Isthmus of Panama, that have ever lived on Earth are and India would meet the Asian extinct. continent, forming the Himalayas. ✓ This is due to mass extinctions events ✓ The first hominids appear toward the that wiped out organisms in the past end of this period in Africa. ✓ FOSSIL -naturally preserved remains or traces of animals, plants and other  organisms that lived in the geologic ✓ from the elements and predators. past, usually regarded as more than ✓ This can happen by: 10,000 years old. ✓ Most fossils are the remains of extinct ❖ being covered in sediment in areas of organisms — that is, they belong to high sedimentation such as the bottom plants and animals that are no longer of a lake living anywhere on Earth. ✓ The kinds of fossils found in rocks of ❖ being trapped in amber or volcanic ash different ages differ because life on Perfect Environment Condition Earth has changed through time. ✓ A lot of fossils are found in sedimentary ✓ Picking the perfect environment is key. rock. This is rock that has been formed ✓ Water is one important thing to from things like sand, mud and small consider. pieces of rock. ✓ If you die in a dry ✓ Most fossils are invertebrates, that is, environment, once you’ve animals without backbones. Worms, been picked over by scavengers, insects, and clams are all invertebrates. your bones will probably 95% of all living animals are ✓ weather away at the surface. invertebrates. ✓ Instead, most experts agree you need to ✓ Insects make up a very large percentage get swiftly smothered in sand, mud and of all animals, but very few of them are sediments – and the best places for that likely to be preserved as fossils. are lakes, floodplains and rivers, ✓ On the other hand, organisms like ✓ or the bottom of the sea. vertebrates will leave a more complete ✓ ‘anoxic’ environment: one very record of their existence, even though low in oxygen, where they are less abundant. animals and microorganisms that would ✓ Fossils occur around the world but a digest and disturb your remains can’t small proportion of life (10%) makes it survive. into the fossil record. Type of organism TYPES OF FOSSILS ✓ Some organisms have only soft body 1. MOLDS AND CASTS parts that have a lower chance of are a type of fossilization where the being preserved because they simply physical characteristics of organisms are decay too quickly, while others have impressed onto rocks, especially coarse hard body parts such as shells, bones or porous rocks such as sandstones. teeth that have a greater chance of Typically, the hard parts of an organism being preserved. leave the best impression, because Be buried rapidly and quickly they are usually composed of calcium carbonate, calcium ✓ In general,for an organism phosphate, silica, or chitin, which to become fossilized, provide a rigid structure and do not it needs to be buried rapidly in decay as easily. order to be protected  The rigidity of the hard body parts commonly characterized as impressions left by allows the sediment to form around snails or worms crawling, jelly-fish dragging its the organism, as opposed to soft body tentacles, or the markings left by the parts which decay too fast for movements of crustaceans or sea urchins. Trails impression to form as well as being too are often made on the soft sediment beneath soft for the mold to set. the water surface. c. Coprolites/ Fossilized Dungs 2. PETRIFIED are the fossilization or preservation of the contents of the intestine and the excrement of occurs when the organic matter is organisms, or quite simply they are fossilized completely replaced by minerals and feces. the fossil is turned to stone. This generally occurs by filling the pores d. Gastrolith of the tissue, and inter and intra cellular also called a stomach stone spaces with minerals, then dissolving or gizzard stone, is a the organic matter and replacing it with rock held inside a gastrointestinal tract. minerals. e. Burrow Fossils 3. Original Remains Burrow -hole or tunnel excavated into the Fossils that are the actual bodies or ground or seafloor - by animals to create a body parts of organisms. space suitable for habitation, temporary Original remains are found in places refuge, or as a byproduct of locomotion where conditions prevent the preserved in the rock record. decomposition, or breakdown, that normally occurs. f. Nest Fossils 4. Carbon Film is the trace fossil that provides evidence of a deliberate construction made by adult dinosaurs two-dimensional image imprinted delicately to provide a site for incubation. Nests can have into sedimentary rock. different shapes, but very few nests are known 5. Trace/ Ichnofossils in the fossil record. is a fossil record of biological activity but not the preserved remains of the plant or animal itself. WAYS OF FOSSILIZATION a. Tracks are the markings of movement that 1. Unaltered preservation vertebrates leave (i.e. "foot prints"). When birds organic matter that is present has not changed or other animals search for food, they would into another substance often walk over mud flats of rivers or seas. A. Ice Because these grounds are typically moist, the organisms leave an impression of their feet Ice is one of the best preservers of the remains (claws, paws, etc.). of prehistoric life. Huge ice fields in Siberia and Alaska contain the bodies of 10,000-year-old b. Trails are similar to tracks, but their patterns mammoths and prehistoric rhinos, with bones, are more irregular as trails are markings muscle, skin, and even hair still in place. B. Amber Amber forms from resin, a sticky substance 7. Desiccation inside trees that flows like syrup and protects also known as Mummification the tree by trapping insects. If the tree gets buried after it dies, the resin can harden into is a very unique and rare form of amber. Amber can contain the remains of fossilization. insects and other small organisms. Bones and tissues of these desiccated organisms of the desert are preserved, C. Tar although they often fall apart at the slightest touch. The original remains of animals have also been With desiccated fossils, even the skin found in places where there were pools of tar— and hair retain their original color. a thick, oily liquid. *sorry for the typos and infos that are not included* 2. Permineralization/ Petrification *All infos are from our GenBio teacher* The organic contents of bone and wood are replaced with silica, calcite or pyrite, forming a rock-like fossil ~ WISHING Y’ALL LOTS OF LUCK!~ 3. Replacement hard parts are dissolved and replaced by other minerals, like calcite, silica, pyrite, or iron 4. Carbonization or Coalification the other elements are removed and only the carbon remained. 5. Recrystallization hard parts are converted to more stable minerals or small crystals turn into larger crystals involves a change in crystal structure, but not a change in mineral chemistry, similar to recrystallization in metamorphic rocks. 6. Authigenic preservation replicates surface form or outline (molds and casts) prior to distortion by compression and, depending on cementation and timing, may intergrade with fossils that have been subject to compression.