ELS REVIEWER PDF (WEEK 1-3)

WEEK 1 THEORIES OF THE ORIGIN OF LIFE Theory of Special Creation - theory that describes life is created by divine power God. Cozmozoic theory- life did not arise in our planet, was descended from other planet where life existed previously. Microorganisms from space came on earth along with meteo...

WEEK 1 THEORIES OF THE ORIGIN OF LIFE Theory of Special Creation - theory that describes life is created by divine power God. Cozmozoic theory- life did not arise in our planet, was descended from other planet where life existed previously. Microorganisms from space came on earth along with meteorites and comets and then evolved into higher organisms in water. Abiogenesis theory - the natural process of life arising from non-living matter such as simple organic compounds. Biogenesis Theory - by Francisco Redi that life can only come from life, and it refers to any process by which a life form can give rise to other life forms. Oparin-Haldane hypothesis - by J.B.S Haldane life arose gradually from inorganic molecules, with "building blocks" like amino acids forming first and then combining to make complex polymers. CHARACTERISTICS OF LIFE  Able to respond to the environment through a stimulus  Growth and development ensure that the offspring will grow up and exhibit many of the same characteristics  Highly organized and structured, following a hierarchy that can be from small to large Energy is the ability to do work. It is needed by all living things and every living cell to carry out life processes. Evolution is the change in heritable traits of biological populations over successive generations Regulation is what allows an organism to handle the effects of a perturbation  When there is reproduction, genes with DNA will be passed from generation to generation to ensure that the offspring belong to the same species having similar characteristics  Biodiversity is essential for the processes that support all life on Earth In Physics energy is defined as the capacity to do work causing displacement of an object Gravitational potential energy /PE=mgh m = mass g = gravitational force 9.8 m/s2 h = height WEEK 2 Cyanobacteria started to evolved 2.5 B years ago, these marked the beginning of eukaryotic cells. Protozoans, fungi, sponges started to exist to soft bodied animals and eventually to complex plants and animals. Robert Hooke  First viewed cells of a cork plant using a microscope  Thin slice of cork had tiny compartments similar to those of a honeycomb Cellulae- "small rooms" but later used the shorter word "cell" Cells - organization made up of a complex system that carries out the cell's function and enables it to adapt to its environment. It is the basic structural unit of each living thing on Earth. Cell Types Prokaryotic cell Eukaryotic cells 'pro' pre, 'karyon'= eu' true, 'karyon'= nucleus nucleus Originated about 3.5 Originated about 1.2 Bya Bya Primitive forms Advanced Unicellular Multicellular No true nucleus True nucleus present Small in size Larger in size 1-2 membrane Several membranes bound organelles bound organelles Cell membrane  the flexible boundary of a cell  separates a cell from its surroundings Nucleus  Largest organelle in the cell and it is the most inner compartment of the cell  Contains (DNA) genetic information on strands called chromosomes  "Control center" for cell metabolism and reproduction Ribosomes - make proteins (made up of RNA and protein); thought of as "factories" Cytoplasm clear gel like fluid inside the cell, which suspends all organelles Endoplasmic Reticulum- extensive network of membranes Rough ER: with ribosomes Smooth ER: with no visible ribosomes Golgi Apparatus - sorts proteins made by the ribosomes and sends them to needed places in the cell Lysosomes- organelles that are filled with digestive enzymes to remove waste and invading bacteria breakdown materials such as lipids, proteins and starch Mitochondria - often referred to as the "powerhouse" of the cell release energy for the cell it converts the energy stored in glucose into ATP for the cell Vacuoles- fluid filled organelles enclosed by a membrane store material such as food, sugar, water, and waste products Mitochondria and chloroplasts resemble bacteria in their size and shape. They are believed to evolved from bacteria as explained in endosymbiotic hypothesis. PLANT CELL ORGANELLE Cell wall rigid wall outside the plasma membrane. It provides the cell with extra support. Chloroplasts captures light and energy; and converts it into chemical energy, contains chlorophyll Large vacuoles organelles that store things such as food in the plant cell  Plants contain large vacuoles when compared to animal cell. What do you think is the function of vacuoles in plants  In microbiology Escherichia coli (E. coli) bacteria normally live in the intestines of healthy people and animals.  WEEK 3 Sexual Reproduction- male and female gametes fuse during fertilization, offspring will develop from the fused genes with a unique set of genetic material. Monoecious or Hermaphrodites  Organisms with both male & female systems  Flatworms & Earthworms Binary Fission - Simplest process of asexual reproduction wherein the body of an organism divides into new bodies. The organism duplicates its DNA then separates, wherein both new bodies receive a copy of the DNA of the original organism Budding - Outgrowths or Buds develop on the parent organism. Buds may break off and develop into a new organism or remain attached to the parent organism Fragmentation - An organism's body is divided into 2 or more parts, wherein each fragment develops into an organism like its parent Parthenogenesis - This occurs when the embryo of an organism can grow and develop without fertilization. In which an egg can develop into an embryo without being fertilized by a sperm Regeneration- detached parts of some organisms can grow back VASECTOMY AND TUBAL LIGATION  During tubal ligation, the fallopian tubes are cut, tied or blocked to permanently prevent pregnancy  Vasectomy works by stopping sperm getting into a man's semen, the fluid that he ejaculates. The tubes that carry sperm from a man's testicles to the penis are cut, blocked or sealed with heat WEEK 4 Ecology is the branch of biology that deals with the relations of organisms to one another and to their physical surroundings. Ecosystem is a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life.  contain biotic or abiotic factors THREE CONDITIONS OF A STABLE ECOSYSTEM 1.There should be constant supply of energy (sun) 2. There must be living organisms that can convert the energy into organic compounds 3.There must be recycling of materials between organisms and the environment LEVELS OF ORGANIZATION 1. Population is a group of organisms of the same species that live in the same area at a specific point in time and they can interbreed with each other includes all members of a species in a given area. (ex., all toad and tadpoles in a pond) 2. Community refers to all the populations of organisms that interact in a certain area (toads, tilapia, guppies in a pond) 3. Ecosystem composed of the living (biotic) and non-living (abiotic) physical environment functioning together in an ecosystem. 4. Biosphere is the portion of the earth in which life exists and is made up of many complex ecosystems. All ecosystems together make up biosphere. TYPES OF INTERACTION Competition - when two species in an ecosystem need to share a valuable and often limited resource. Such as food or water, they are in competition with each other. Symbiosis- the way in which two different species living together in the same community, interact with each other over a long time period. This can occur in the form of parasitism, mutualism or commensalism. Parasitism- is when the one species benefits or gains something from the relationship and the other species is harmed in some way. The host may die in some interactions. Mutualism- occurs between any two species where both of the individuals benefit from the interaction. Both species gain something from the other, so we can say it is mutually beneficial. Commensalism- the one species benefits, while the other one is unaffected by the relationship. Unlike parasitism, in commensalism the other species is not harmed or benefited in any way. Feeding- when one species can use the other species as a food source. For example, in predator-prey relationships, the one species (predator) will hunt another species (prey). FEEDING TYPES Producers/Autotrophs - are organisms that can synthesize organic molecules from inorganic molecules can be photosynthetic or chemosynthetic Consumers/Heterotrophs are organisms that cannot manufacture organic molecules Herbivores - organisms that eat only plants. Also called primary or first level consumers (cows, goats, carabaos) Carnivores - organisms that eat only other animals. Can be secondary/tertiary/quarternary consumers. (dogs, cats, wolves, bears) Decomposers they recycle dead organisms and waste by reducing it into chemicals such as nitrogen and carbon. Those chemicals become part of the soil and can be used by living plants and animals that consume them. Food Chain- shows the pathway of energy from one organism to the next in a direct line of organisms. Food Web- shows the interactions and interconnections among the different food chains of a community. It shows that most organisms eat, and are eaten, by more than one species. Energy pyramid represents quantitatively the numbers of organisms, energy relationships, and biomass of an ecosystem. LAWS OF THERMODYNAMICS 1st Law of Thermodynamics - Law of Conservation of Energy "Energy cannot be created or destroyed, they are transformed from one form to another." 2nd Law of Thermodynamics - Law of Entropy; the entropy of the world only increases and never decreases so during transformations, energy in form of heat is lost. WEEK 5 Genetically modified organism/Transgenic plants and animals  Express DNA that has been modified or derived from another species.  It is done through the process of Genetic Engineering the modification of genetic material to achieve specific goals Genetic Engineering - refers to specific gene transfer from the same or related or unrelated species resulting in the gene fragment modification and recombination to produce new trait(s) in an organism. Recombinant DNA Technology contains genes or portions of genes from different organisms, often from different species. TRANSGENES 1. BACTERIAL MEDIATED  Bacterial carriers 2. NON-BACTERIAL MEDIATED  Microinjection Nuclear transfer  Biolistics Electroporation 3. VIRAL TRANSFER  Retroviral vectors Polymerase Chain Reaction (PCR) - makes copies of specific regions of sequenced DNA. It is used to copy DNA for any scientific investigation including forensic analysis and medical testing. Restriction enzymes - are enzymes that cut double stranded DNA into fragments at very specific locations. Ligases are enzymes that join together "cut" strands of double stranded DNA. Gel Electrophoresis - separates DNA fragments by size. It is used to study DNA fragments of various sizes. DNA Sequencing - is used to identify the DNA sequence of cloned recombinant DNA molecule to further study. It is used to identify errors in the DNA sequences to predict the function of a particular gene Gene Cloning It is used to create large amounts of recombinant DNA to be used in genetically engineered organism PLANT GENETIC MODIFICATION  Genetically heterogeneous population of plants is inspected, and "superior" individuals plants with the most desired traits, like improved palatability and yield are selected for continued propagation. ANIMAL GENETIC MODIFICATION  Assisted reproductive technologies; use of naturally occurring hormones, such as recombinants, and biotechnologies to enhance reproductive efficiency without affecting the genome; and biotechnologies to enhance expression of desirable genes. MICROBE GENETIC MODIFICATION Microorganisms play significant roles in food production like food fermentation and in food spoilage, and they can produce enzymes or other metabolites used in food production and processing. Food, wine, bread, and cheese popular, depend on microbial ingredients and activities. GAINS FROM GMO ISSUES ABOUT GMO 1. Disease-resistant  Biosafety to environment  Possible effects on nontarget organisms and biodiversity 2. Insect-resistant and  Possible crossing with relatives to produce weeds 3. Drought-tolerant crops  Possible formation of resistant insect population  Possible persistence in the environment Food safety to humans  Possible allergenicity and toxicity  WEEK 6 Four basic types of digestive systems 1. Monogastric digestive system has one simple stomach that secretes acid. This acid destroys most bacteria in the stomach and break down the foods into its simplest form. 2. Avian digestive system is found in poultry, animals that do not have teeth. They break their food into small pieces by pecking it with their beaks or scratching them before swallowing. Food enters the mouth, travels to the esophagus, and into the crop.  The CROP is where the food is stored and soaked.  The food moves to the stomach of birds called proventriculus where the gastric enzymes and hydrochloric acid are secreted.  Gizzard, a very muscular organ, which contains stones that act like teeth to grind the food. 3. Ruminant digestive system has a large stomach divided into four compartments—the rumen, the reticulum, the omasum, and the abomasum. 4. Pseudo-ruminant digestive system is found in animals that eat large amounts of fiber but do not have stomach with several compartments. Types of Respiratory Systems HYDRA have no respiratory organs. Gases are exchange directly by diffusion between the organism and environment through the epidermal cells. EARTHWORM the surface of the skin has a film of moist, mucus-like material where gas molecules dissolve and diffuse GILLS of some aquatic animals like crustaceans, mollusks provide a large respiratory surface. Oxygen and carbon dioxide are exchange between the blood surrounding the gills and the watery environment. Introduction EVOLUTION EVOLUTION the process by which new species or populations of living things develop from pre-existing forms through successive generations- Charles Darwin; On the Origin of Species by Means of Natural Selection (1859) Evolution states that all species are related and change over time. Occurs in order for more advantageous traits to pass down to the next generation, thereby ensuring the continued survival of the species. Natural Selection the process, by which those individuals whose traits are more advantageous leave a larger number of offspring. Over many generations, this differential or unequal reproduction among individuals with different genetic makeup changes the overall genetic composition of the population. Main points of Darwin’s natural selection 1. Overproduction. Over time environmental pressures limit the number that can survive even population increase in size 2. Variation. Organisms differ in size, behavior, and other features 3. Competition. Organisms within a population must compete with each other to survive 4. Survival of the fittest. The individuals who are best adapted to that environment are likely to survive 5. Reproduction. Individuals that survive and reproduce can pass their traits on to their offspring 6. Speciation. When a population differs enough from the original population, it is a new species.  A Postcript by Charles Darwin “There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” 1.Carolous Linnaeus Father of taxonomy, started the binomial system of nomenclature 2. Jean Baptiste de Lamarck First to propose about the theory of evolution Theory of inheritance of acquired traits and theory of use and disuse 3. James Hutton The concept of uniformitarianism 4. Georges Cuvier Established extinction through fossils. Theory of catastrophism 5. Gregor Mendel Law of segregation (two alleles for each gene separate during gamete formation) and Law of Independent Assortment (alleles of genes on nonhomologous chromosomes assort independently during gamete formation 6. Alfred Russel Wallace Natural selection of inherited traits could give rise to new species EVOLUTION Evidences of Evolution Fossils provide evidence of evolutionary change over time - It also documents large scale evolutionary transitions Ex. The link between dinosaurs and birds was confirmed by dinosaurs with feathers Human Ancestry Hominids are humanlike species that were similar to modern humans in some ways. The first hominids are genus Australopithecus found in Tanzania and Ethiopia. The oldest one is named Lucy which lived 4 m.y.a Australopithecus afarensis. Homo habilis lived nearly 2 m.y.a have larger brains and teeth which are more like of modern humans. Homo erectus hominid fossil ranging in age from 1.5 to 0.5 m.y. found in Java and China in which brain size is comparable to modern humans. Made stone axes and campfires. Comparative Anatomy Homologous Structure – are parts of different organisms that are similar in structure but serve different functions Forelimbs of human, dog, bird and whale Analogous structures Are similar in function but differ in internal structure. It does not suggest evolution from common ancestor Phylogeny – describes the relationships of an organism, such as from which species it is most closely related, and which organisms it is thought to have evolved Other Evidences of Evolution Molecular biology – DNA and the genetic code reflect the shared ancestry of life. DNA comparisons can show related species are. Biogeography – The global distribution of organisms and the unique features of island species reflect evolution and geological change Comparative embryology – certain organisms show strong similarities in the development of embryos Cladogram – is a diagram that describes evolutionary relationships among groups. It is based on phylogeny which is the study of evolutionary relationships. Cladistics - sorts organisms into clades, a group of organisms that descended from a single ancestor is a classification based on common ancestry Genetics Gregor Mendel, through his work on pea plants, discovered the fundamental laws of inheritance due to his works the gaps in Darwin’s theory were explained. Geographic Distribution of Related Species The most likely explanation for the existence of Australia’s New Zealand’s,and Hawaii’s mostly unique biotic environments is that the life forms in these areas have been evolving in isolation from the rest of the world for millions of years. HOW HUMAN ACTIVITIES AFFECT THE NATURAL ECOSYSTEM Factors that disrupt balanced ecosystem: (1) natural factors; and (2) human factors. 1. Natural factors- Natural disasters like floods or hurricanes can cause severe disruptions to ecosystems, but the ecosystems recover eventually. If the change occurs over long periods, like climate change and global warming, the damage may not be reversible. For example, there are many different theories about why the dinosaurs become extinct. One of the main theories is a sudden change in climate. This sudden change, whether it was due to a meteor striking earth or not, disrupted the balance in the ecosystems. It was to such an extent that all the dinosaurs died out.  2. Human factors- Many years ago, people like the San (first nations of Southern Africa,) had little impact on their environment, as they lived in harmony with the land and only took what food they could carry. Modern man has, however, had a huge effect on nature. We clear land to build cities, roads and farms, we pollute the environment and produce waste and litter. Humans also poach endangered animals and over-harvest marine animals, causing lasting damage to ecosystems. Another way in which humans have a huge impact on the environment and cause disruption to ecosystems is through pollution. ADAPTATIONS- Organisms in ecosystems face competition, predation, parasitism and human influence, all of which could affect them negatively, forcing them to adapt, move away or die. Adaptation in species can occur in three main ways: 1. Structural- the physical characteristics of a species such as having long legs and strong muscles. 2. Functional- a species may have special way of carrying out its life processes. 3. Behavioral- the species can have special behaviors that are instinctive (which they know by instinct) or can be learned such as making safe nests for protecting their babies. OTHER BEHAVIORAL ADAPTATIONS MIGRATION - This occurs when an animal or a group of animals move between different areas at different times or periods. HIBERNATION –is a way animals conserve energy to survive adverse weather conditions or lack of food. It involves physiological changes such as a drop in body temperature and slowed metabolism. - inactive state of animals especially during winter. Some of them sleep through a whole winter, while some hibernate by burrowing into the mud when the pond dries up, until the rains return. Conservation of the ecosystem Ecosystems are able to naturally recycle materials like water, carbon dioxide and other gases and the remains of organisms, if they are left alone. But ecosystems cannot do this effectively if we interfere. These human interferences include: - Habitat destruction like deforestation and burning - Pollution causing global warming - Alien invasive plants taking over ecosystems - Hunting, poaching and other killing of wildlife