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BIOL 1001
Tamara Kelly

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SPECIES – CLASSIFYING, DISTRIBUTION, ISSUES WITH DEFINING WHAT A SPECIES IS Explain, in general terms, how the Earth’s shape affects the intensity of solar radiation across latitudes. O Firstly the Earth is spherical in shape; this means that at the 0 latitude point (the equator), is relatively flat compared to the upper portions of the planet and because of this curvature , the sunlight is not as direct, but is spread out on a larger area at higher latitudes. Define the three different types of biodiversity (species, community/ecological, genetic). - Species: The number of species in an ecosystem. - Community/Ecological: The number of communities in an ecological system. - Genetic: The number of alleles in a species. Define (terms describing the hierarchy of life): biosphere, ecosystem, community, population, multicellular organism, and cell. - Biosphere: All regions of Earth that sustain life (includes all things biotic and abiotic). - Ecosystem: Group of communities interacting in their shared environment. - Community: Populations of species that occupy the same area. - Population: Group of organisms that belong to the same species. - Multicellular Organism: Organism consisting of multiple cells. - Cell: Simplest unit of life. Use the terms species, individual and organism appropriately. - Species: Lowest in hierarchy of the eight taxonomic ranks. Often defined as a group of organisms capable of interbreeding and producing fertile offspring. More precise or differing measures are often used, such as similarity of DNA, morphology or ecological niche. - Individual: One specific organism (e.g. Dr. Kelly is an individual). Explain how the term ‘species’ can vary between groups of organisms. Not all organisms belong to the same species. For example, some may be able to inbreed, but differ in morphological features. Explain briefly how an organism can be classified according to factors other than physical features. An organism can be classified by the fact of whether or not they can successfully inbreed how many genetic traits they share with each other, what ecological niche they belong to, etc. One all this information is gathered organisms and be split up taxonomically from: Domain>Kingdom>Phylum>Class>Order>Family>Genus>Species Define abiotic, biotic, and species richness; describe, in general terms, abiotic and biotic factors that affect species distribution/richness. - Abiotic: Physical rather than biological (e.g. sunlight) - Biotic: Living/biological (e.g. animals). - Species Richness: Rich (or large) number of species in a given area. Abiotic factors that affect species richness include sunlight (e.g. some species can only live in an area with high sunlight), temperature (e.g. some species may have a low tolerance to cold weather), pH (e.g. some organisms can only live in acidic environments), atmosphere (e.g. some species may require a large and constant amount of oxygen gas), etc. Biotic factors that affect species richness include trophic interactions (e.g. consumers and decomposers must maintain an equilibrium), movement of energy (e.g. a bison can obtain energy from a plant that obtained energy through photosynthesis), biomass (e.g. an energy source, that is biological material from living, or recently living organisms), predation (predators must feast and control the number of prey so that they can keep themselves alive, and control the prey population), etc. Describe the cause of variation in solar radiation intensity and seasonality on Earth. The axis of the Earth is what causes seasons. Since the axis is tilted, different parts of the globe are oriented towards the Sun at different times of the year (e.g. Canadian summer is Australian winter). Summer is warmer than winter (in each hemisphere) because the Sun's rays hit the Earth at a more direct angle during summer than during winter and also because the days are much longer than the nights during the summer. During the winter, the Sun's rays hit the Earth at an extreme angle, and the days are very short. Relate trends in biodiversity to latitude. Most organisms cannot stand cold conditions, therefore as you move further away from the equator (in both directions), the amount of biodiversity decreases. Although, since most life on Earth prefers warmer climates, as we move closer to the equator, biodiversity increases. Provide two examples, each, of biotic and abiotic factors that can affect species distribution. - Biotic: Predation; if predation is too great in one area then all the prey die off which eventually lead to the death of the predators, thus decreasing the amount of both species in that area. - Biotic: Biomass; there will be a greater distribution around areas with higher biomass, since it can be consumed for energy. - Abiotic: Temperature; There will be a greater distribution of species in a warmer climate vs. a colder climate (e.g. Amazon Forest vs. Northern Canada), as most species cannot handle cold temperatures, and find a better equilibrium within themselves and their environment in warmer systems. - Abiotic: Precipitation; perhaps for species that use photosynthesis (e.g. plants), they will have a greater species distribution in areas with greater precipitation than in areas that do not. List three challenges of living on land, compared to life in water. - Gravity: The effects of gravity are more prominent in a medium like air compared to water. - Conservation of Water: It is much harder to conserve and retain water in your body on land as opposed to living in a body of water. - Reproduction: On land all reproduction must be done internally, not externally like it can be done in the water. In the water a mother can lay her eggs and a male can fertilise them; impossible on land; eggs would lose their water on land. Provide one advantage each for life aquatic and terrestrial lifestyles. Aquatic: Must easier to retain water. Terrestrial: Stronger access to sunlight. Define the following terms: trophic level, primary producer, consumers (primary, secondary, and tertiary), omnivores, detritivores, and decomposers. Trophic Level: The feeding position in a food chain (e.g. primary producers) Primary Producer: An autotroph; a member of the first trophic level. They produce biomass from inorganic compounds. Primary Consumer: Heterotrophs that consume autotrophs (e.g. A cow eats grass) Secondary Consumer: Carnivores which eat herbivores. Tertiary Consumer: A carnivore at the topmost level in a food chain that feeds on other carnivores; an animal that feeds only on secondary consumers. Omnivore: Species that eat both plants and animal material as their primary food source (e.g. humans). Detritivores: Heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as organic fecal matter); they contribute to decomposition and the nutrient cycles. Decomposers: Heterotrophic organisms that break down dead or decaying organisms, and in doing so carry out the natural process of decomposition while using the deceased organisms and non-living organic compounds as their food source. (e.g. bacteria, fungi, etc.) Assign each of the trophic levels (from primary producer to tertiary consumer) one of the following labels: photoautotrophs, heterotrophs. 1. Tertiary Consumer = Heterotroph 2. Secondary Consumer = Heterotroph 3. Primary Consumer = Heterotroph 4. Primary Producer = Photoautotroph Explain how the activities of detritivores and decomposers are crucial to community function. The role of detritivores and decomposers is to simply break down compounds that are in unusable forms into organic molecules that can be used by other organisms. For example, decomposers take organic waste from the ground and convert the nitrogen in it into nitrates that make the soil fertile for plants that can convert the nitrates into usable amino acids. Thus they play a key role in the nitrogen fixation cycle, among others. They are essentially the blue bins of nature. NATURE OF SCIENCE Describe subject matter appropriate to scientific study (describe the limitations of science as a means to answer questions). The only subject matters appropriate to scientific study are those of the natural/physical world (e.g. viruses). These things have to be testable and measurable in some way. What science cannot study are subjects of the supernatural (e.g. God). Describe how science is a process and how the scientific method is flexible in nature. Science is a process, because you have to go through questions. You need to question something, then make a hypothesis (or multiple hypothesises), then collect data from a designed experiment, and finally show conclusions to support or refute the original hypothesis(s). This process is flexible in nature, because there is no one way of going out to collect and formulate data. You can continue to add sub-processes to the scientific method to cater to your study, essentially you have a template (the scientific method) and you can change it any way to suit your work. You can also easily change your hypothesis as new data and studies emerge, thus making it ever changing and self- correcting. Describe how ‘choices’ are made among alternative hypotheses in science. You test the hypotheses and see which one(s) the data supports. From there you refine your hypotheses as you collect and analyze more data until you can settle on the hypothesis that has the most support from evidence. Identify pseudoscience and anecdotal evidence masked as scientific evidence. Pseudoscience: Fake science (e.g. four out of five dentists) that make scientific-sounding claims; usually from unreliable sources. Anecdotal Evidence: Based on a few observations, people simply claim there is/isn’t a link (correlation) between two things (e.g. as global warming increases number of pirates decreases); it is also no rigorously studied. Define and differentiate between the following pairs of terms: theory & hypothesis; evidence & proof; believe & accept; function & purpose; primitive/less evolved & advanced/more evolved. Theory & Hypothesis: A theory can be made up of many well supported hypothesises; it is a system of ideas that, with support from evidence, explains a phenomenon of the natural world. A hypothesis is a precursor to a theory; it is an idea that needs to be tested to be supported or refuted by evidence. A hypothesis like a theory attempts to explain something of the natural world, but a hypothesis is not as supported in the amount of evidence as a theory. Evidence & Proof: In Biology nothing can ever be proven to 100% certainty. Things can only be given more and more evidence to support or refute it. A proof has more of a place in mathematics and such places where there are absolute laws to things (e.g. addition). Even if something is highly supported in Biology (e.g. evolution), you can still refute it, no amount of evidence can make anything completely proven. Evidence is simply observations that are taken from the natural world that contributes to the idea of a hypothesis. Believe and Accept: You never have to believe anything; you can always refute things (e.g. God), but in terms of acceptance, you, whether you like it or not, need to accept the evidence for something (e.g. evolution). You must accept the evidence for something (assuming it is sound, but you can always refute the way the evidence was found and such), but you need not believe all theories; if many people did not refute the theories of their day that seemed iron clad we would have not moved on very far as a scientific community (e.g. phlogiston). Function & Purpose: Something’s function need not necessarily be its purpose. A function describes what something does (this is not necessarily its purpose), and purpose is the aim or goal of something. For example a tree does not grow any flowers for any purpose, it has simply evolved to. Another example is the computer, its purpose is widely scoped (e.g. do complex calculations), but to someone its function can simply be to surf the web. Primitive/Less Evolved & Advanced/More Evolved: Firstly, these terms are relative; you must compare them to something else. For example, in terms of human beings, the camera eye is more evolved than the pinhole eye. In general sense, humans will do better with a camera eye, but this is not the case for all organisms that have older types of eyes that are, relative to the camera eye, less evolved. Also you cannot justly compare two unrelated things together and say something is more/less evolved than the other (e.g. eyes vs. limbs). So to say that something is more evolved than something else means that it has just gone through more evolutionary changes throughout time to alter its features. Compare and contrast ‘hypothesis’ and ‘theory’ when used in a scientific context. Hypothesis Similarities Theory - An idea. - Both can easily be - Well supported by - May not be widely discredited. evidence. accepted. - In the scientific sense, - Stem from hypothesises, they relate to the natural supported by evidence. world. - Much more broad than a - Try to explain a natural hypothesis. phenomenon. OVERVIEW: EVOLUTION, PHYLOGENETICS, AND HISTORY OF EVOLUTIONARY THOUGHT Define the theory of evolution. Biological evolution is a change throughout time. Microevolution is short term change for a genealogy (e.g. fruit flies experiment); while macroevolution is change throughout a long time in a phylogeny (e.g. water to land transition). Describe how evolution explains (or is responsible for) the unity and diversity of life on Earth. Evolution explains the existence of “intermediate” type species (e.g. tiktaalik). It also explains how aquatic creatures could have come above onto land, and how that they are on land; they can produce ATP more efficiently (since there is more oxygen gas present) and greatly multiply and diversify. It also shows how different types of species exist that are very related to each other (e.g. Darwin’s finches). Explain how evolution ‘works’ making reference to populations, individuals, and reproduction. Evolution works when there are selective pressures on a population that through natural selection have the populations with favourable traits survive and reproduce. Evolution does not happen to a single individual, it happens to groups of populations over time through natural selection. Describe characteristics of model organisms ideal for evolutionary studies (be sure that you can explain why these are ideal characteristics). These characteristics include being able to reproduce in massive numbers (so you don’t have to breed so many), small in size (so they can be contained), have a short lifespan (so you can view many generations), and be easy to maintain. Define key terms (phylogenetics): systematics, morphology, phylogeny, taxonomy, classification, taxonomic hierarchy, taxon, lineage, monophyletic taxa, common ancestor, paraphyletic taxa polyphyletic taxa, principle/assumption of parsimony, mosaic evolution, ancestral characters, and derived characters. Systematics: Study of the diversification of life. Morphology: Physical structure and features of an organism. Phylogeny: Study of evolutionary relatedness. Taxonomy: Hierarchy based classification of organisms. Classification: Arrangement of organisms into hierarchal groups. Taxonomic Hierarchy: Hierarchal order of classification (e.g. Linnaean system). Taxon: One section of the hierarchy (e.g. order). Lineage: Sequence of species that decent from the pervious. Monophyletic Taxa: Includes a common ancestor and all of its decedents. Common Ancestor: A node on a phylogenetic tree; a point where other species decent from. Paraphyletic Taxa: Includes an ancestor species and some of its decedents. Polyphyletic Taxa: Includes species from different lineages (e.g. warm blooded). Principle/Assumption of Parsimony: Assume the simplest explanation. Mosaic Evolution: The rate of evolution varies within and between species. Ancestral Characterises: Characterises acquired by genetics from a perviou
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