Bio Final Summaries
Course Syllabus…
Science Safety Rules…
Observation Skills: As observations are actively acquired from a primary source with the senses, it is essential to respect organisms. Observations are essential in science. These observations can be quantitative (containing numbers and measurable), qualitative (not containing numbers and not measurable), or inferences (assumptions based on evidence).
Introduction to the Owl Diet Lab: Barn owls eat other organisms in their open habitats. They can fly without noise, swallow their food whole, and regurgitate pellets containing animal matter that they cannot digest. While an inference is not necessarily fact, an observation is typically fact.
Owl Pellets in the Classroom: Safety Guidelines…
Owl Pellet: Initial Observations: We start observations with safety and qualitative observations. We use these preliminary observations to form a hypothesis. Then we make quantitative observations with measurements and summarize/compile our data. Last, we ask questions.
Owl Pellet: Dissection and Collecting Preliminary Data: Since science seeks truth, new discoveries bring us closer to the truth. An experiment is not testing a hypothesis, and observation and collecting data are the most basic skills of science. We can use figures and images, like one of the bones in a vole, to inventory the bones in an owl pellet.
Owl Pellet: Collect Data, Analyze Data, and Summary: One can use a dichotomous key to identify a specific species. We found 5 full vole skulls in our owl pellet. Then, we inventoried the bones using bone pictures from our species. We used a formula to calculate the inferred number of organisms per pellet. We then analyzed our class data. In summary, our owl consumed 5 voles. Our owl pellet contained 4 skulls that we identified, as well as 10 vole mandibles. Owls tend to eat small live rodents, including voles, pocket gophers, shrews, mice, and rats. Our class data shows that out of all our owls’ pellets, 82% of organisms were voles, while 2%, 12%, and 4% represented pocket gophers, shrews, and mice/rats, respectively.
Dichotomous Key: A dichotomous key lists steps that differentiate between two species, leading the user to skip steps, continue on, or end their search at each step. It can also include a figure with branches to differentiate between species using specific characteristics between the branches. We followed the key downwards, making a decision at each fork in the road.
Scientific Inquiry Process: an Introduction: Science is learning about the natural world, and there is a model to show various steps in scientific inquiry. These steps are, in no given order: observe, define the problem, form a study question, research the problem (what is already known?), state the expectations (hypothesis), experiment and gather data, analyze the results (by collectively looking at the data with graphs and averages), reflect on the findings (answering the question using data), and communicate with the wider community. Questions and learning from them is the central theme of all scientific inquiry. Then, we studied Redi’s Experiment to learn about his usage of the scientific inquiry process.
Talking About Science Safety…
Introduction to the Science of Biology Study Guide: A scientific observation is a piece of information from a primary source, actively obtained through the senses. There are two types, quantitative and qualitative. A qualitative observation is not numerical and describes a quality. It notes purely what you notice from an object. A quantitive observation requires numerical data, so it is a precise number. An inference is an informed assumption, which should be avoided in science. It is not an observation as it is a conclusion made from the data, and it is not factual like observations. A dichotomous key is a guide with choices that allows one to identify something through the process of elimination. It lists specific animal features and is used by consistently picking between 2 options to find the correct identity.
Is It Alive?: All living things respond to their environments, move, reproduce, gain nutrients, excrete something, have cells, evolve, have a characteristic structure, and are carbon-based.
Characteristics of Life: All living things are made of microscopic, fundamental cells. These organisms can be unicellular or multicellular. Atoms make up molecules, which make up organelles and structures, which make up tissues and organs. These cells have membranes and involve chemical reactions. Life depends on chemical reactions, which rely on energy usage through means of matter consumption. Since all chemical reactions are the metabolism, anabolism crafts larger molecules and consumes energy while catabolism does the opposite. All organisms respond to stimuli. Homeostasis is a response where the organisms maintain their internal environment. Evolution is a generational change in populations, which can happen through natural selection: differential survival and reproduction. The DNA changes as a response to the environment. Living organisms gain matter and mass as growth, so cells become larger and multicellular organisms gain cells. Growth relies on anabolic reactions, while development relies on genetic change. Living organisms reproduce with DNA, either asexually or sexually. Asexual reproduction causes the offspring to be identical to the parent, while sexual gives the offspring half from each parent. Sexual reproduction requires a sperm and an egg cell, called fertilization.
Notes 1: Ecology and Food Webs: Ecology is the study of interactions between living organisms and their environment, which can be divided between biotic and abiotic factors. There are levels of organization in ecology, which goes from a single organism, to a population, to a community, to an ecosystem, to a biome, and finally to a biosphere. Sunlight is the main energy source for all life. At the bottom, producers/autotrophs like plants, algae, and bacteria capture energy from sunlight and make sugars with it. Then, consumers/heterotrophs consume other organisms for their energy. These consumers are divided between herbivores, carnivores, omnivores, detritivores, and decomposers. The energy transfer can be modeled in food chains, which are a series of steps in which organisms transfer energy, or in food webs, which are all of the different food chains together. In either case, there are trophic levels, which are the steps in a food chain or web.
Clarifying Ideas of Ecological Organization: Organisms in their Environment: We discussed examples of each level of organization. A species includes all of the animals, while a population places them in a specific area. A community includes all of the other organisms, unlike the population. The abiotic factors are added to the community to create the ecosystem. A biome is defined by every similar ecosystem as a group. An ecosystem has abiotic and biotic factors. A biosphere includes every biome on Earth. The biome is one group of ecosystems. Biotic factors are alive, while abiotic factors are not alive.
Food Web Practice: We identified the animals at each trophic level and identified them from two different models. For example, the sun gives energy to the green plant. The primary consumers feed on it, and depending on the circumstance, more levels could be added with secondary or tertiary consumers. Last, the lion consumes primary, secondary, and tertiary consumers to get the sun’s original energy. In the beginning, the plant uses the sunlight to make sugar which has the energy that gets transferred.
Calculating Energy in Ecosystems: Since energy cannot be created nor destroyed, energy is converted. Chemical energy is transferred into kinetic and thermal energy like when the body moves and heats itself and when food is pooped out. In the example of a caterpillar’s energy, it loses 50% of its energy in poop, absorbs 16.5% from its food for growth, and uses 33.5% for cellular respiration. Decomposers and detritivores make use of the poop. On average, about 10% of energy is transferred between levels, but it can be between 5% and 20%. The energy is released as thermal energy, as mass through exercise and defecation, or through cellular respiration, so only 0.01% is at the tertiary level. Ecosystems need the continuous supply of the sun’s energy for each level to get enough energy from the level below it.
Notes 2: Ecological Pyramids: Only about 10% of energy is transferred between trophic levels, and a trophic pyramid shows this (with 1% of sunlight stored by plants shown too). The rest is lost as heat. Different energy levels can be represented by models like biomass pyramids and pyramids of numbers. In biomass pyramids, the total amount of food for each trophic level is shown. However, in pyramids of numbers, the approximate number of organisms at each level is shown to show the strengths and weaknesses of a community.
Anchoring Phenomenon: An Endless Swarm: We made essential observations and drafted questions regarding several swarming scenes. Several factors like mating seasons and diseases may cause a typically solitary species to swarm. An advantage could be strength in numbers or lack of competition. Humans could be impacted by sound and could impact swarms through food competition.
Population Ecology Introduction Reading and Questions: A population is all of the individuals in a species that live together in one place and time, and they tend to grow because individuals have multiple offspring in their lifetimes. There are 3 key features that we study: population size, density, and dispersion, but also growth and diversity. 2 risks of a small population would be random events and inbreeding. There are 3 patterns of dispersion, too: random, even, and clumped. Exponential growth happens where the rate of population growth stays the same so the population size increases steadily. There are many factors that limit population growth, though. Carrying capacity, or the population size that an environment can sustain, and density-dependent factors, or limited resources where the rate at which they are depleted depends on population density, both slow population growth. While the exponential model of population growth only shows growth over time, the logistical method also takes into account these slowing factors.
Notes: Population Density, Distribution and Growth: Population ecology studies the interactions between all the individuals in a species that lives together at once. Population size, or the number of individuals in a population, is affected by birth, death, immigration, and emigration, though natural disturbances and inbreeding are the most dangerous. Since population density describes the number of individuals in a specific area, there are certain limited resources where the rate at which they are depleted depenbds on the population density of their users. The way a population is arranged is called population dispersion, which can be clumped with uneven resources or organisms that are social and live in groups, uniform with evenly spread resources or organisms that are territorial, or is random with no pattern seen and fluctuating resources. Population growth happens where multiple offspring from individuals are produced exponentially, but they are limited by their carrying capacity, creating a logistic growth model rather than an exponential growth model.
Population Practice, part 1: We collected data on population size and density in different habitats from a model. We then found the dispersion patterns, and more were found to have a random dispersion. From another model, we found that a higher population density would cause a disease to spread more quickly which would then decrease the population density. Thus, as a population’s density increases, food supply decreases faster, while the other factors increase. Together, they put downward pressure on it. We then studied allelopathy, or the chemical inhibition of one species by another, finding that even distribution but possibly random is most likely to come with it, and that there are both advantages and disadvantages to allelopathy.
Population Practice, part 2: Growth: Density-independent factors like environmental conditions limit the growth of rapidly reproducing populations. These populations are often labeled as r-strategists and are found in rapidly changing environments. On the other hand, slowly growing populations are often labeled as K-strategists and are found in stable environments where the carrying capacity meets their population density. In this way, duckweed are r-strategists. We then analyzed a model, showing us that immigration is when organisms move into a population, emigration is when organisms leave the area and decrease the population, and while death and emigration decrease a population, birth and immigration increase a population. In another model, we found that population growth is so rapid because of plentiful resources so it only slows when population density increases the effect of density-dependent factors and the population is large enough. In most natural populations, rapid exponential growth is unsustainable as environmental resistance causes the growth rate to slow until the carrying capacity is reached. Different factors that occur below or above the carrying capacity keep the population in check and can cause fluctuations in the population size, exceeding or not exceeding the carrying capacity.
Duckweed Observation Lab: The first step of the lab was to observe and learn about duckweed. We made observations by gently observing the duckweed, and we found both quantitative and qualitative observations. Then, we drew several models of the duckweed in the cup, cleaned, and made questions.
Duckweed Research: What is known about Duckweed: Duckweed is a floating, flowering, aquatic plant with a large frond structures, and they can reproduce either asexually or sexually. Duckweed is constantly researched for human use like for a biofuel, as a bioremediator, and as a phytotoxicity tester. It grows in nutrient-rich waters in most areas, but especially in tropical and temperate regions. Duckweed is neither found in the US state of South Carolina nor in many other specific parts of the world, usually owing to wetness, dryness, or cold. It is also a producer, an r-strategist, and important prey. There are many specific abiotic conditions and ranges necessary for it to grow in a specific body of water, like calcium and nitrogen content and pH level. There is a very specific method to counting duckweed, and it is essential to count every single visible frond on the plant. The smallest duckweed species is called Wolffia angusta and has fruits that are sized comparable to a grain of salt.
Practice with Questions, Hypothesis, and Experimental Variables: First, we checked to see if we could answer certain questions scientifically. Then, we checked hypotheses for usefulness and practiced writing likely and useful hypotheses. From a model of an aquatic plant performing photosynthesis, we found that the plant was using light energy and producing oxygen through photosynthesis in its cells. We then developed a method for measuring the gas output and found some environmental factors that could affect it. From a second model depicting an aquatic plant light experiment, we identified similar factors, the independent variable, and drafted a claim with evidence. Varied light was changing the number of bubbles produced. In each consecutive trial, there were 2 less gas bubbles than in the last trial. From no light obstruction to the most obstruction, there was a difference of 6 bubbles. Next, we collected data from the experiment. After, we recapped the variables (independent, dependent, and controlled) and identified the various parts to Harte’s salamander research.
Plan an Experiment Lab: Lab Team Discussion and Decisions: We planned an experiment to answer the question, “under what environmental conditions does duckweed grow the most?”. Our independent variable was adding different amounts of salt. For our experimental groups, we planned that we would add a specific number of miligrams of salt to each cup, corresponding to the milimolar value (30mM, 50mM, and 60mM concentrations). We would round the miligram value to the nearest 0.01. The amounts referred to the lowest in the range, the highest, and the relative highest number (95%). We planned our control group to not have added salt and we drafted a method to find our dependent variable data, regarding the growth of the duckweed. We identified several necessary controlled variables, and developed methods to keep them consistent. We planned to answer the question, “what is the effect of salinity on the duckweed growth as measured by counting each frond?”, and we hypothesized an answer saying that the 50mM value would be most optimal for duckweed growth as measured by counting each frond. Lastly, we concisely summarized our experiment, like the general procedure, controlled variable procedure, and hypothesis.
Study Guide for Intro to Life, Science, and Ecology Summative Assessment: I reviewed variables in an experiment, levels of organization, energy/feeding relationships, energy in trophic levels and ecosystems, and populations.
Notes: Earth’s Spheres and How They Interact: We asked, “why is earth considered a ‘closed system’?”. Since everything in the system has always been there, there are 4 spheres: the hydrosphere, or all of the liquid and surface water of the planet (and ice), the atmosphere, or all of the gases and water vapor, the geosphere, or earth’s core, mantle, and crust, and the biosphere, or all of the living things. Interactions happen with the transfer of energy or matter, especially on the surface of the geosphere. Also, the anthrosphere, which could either be a part of the biosphere or its own sphere, is the part of the environment made or modified by humans.
As earth is a closed system, every part has remained to now. The hydrosphere includes all the liquid water, surface water, and ice of the planet, the atmosphere includes all the gases and water vapor, the geosphere includes the core, mantle, and crust, and the biosphere includes every organism. Interactions between the spheres usually occur on the surface of the geosphere with movement of energy or matter. The anthrosphere, the part of the environment made or modified by humans, is either a 5th sphere or part of the biosphere for it has significant impacts on all the other systems. All in all, the earth includes all of these systems, making it a system itself.
Duckweed Data Table!…
Modeling Interactions in an Ecosystem Practice: We identified the parts from each sphere in a pictorial scientific model. Then, we modeled how the interactions between the biotic and abiotic components worked together.
Notes: Biogeochemical Cycles: Energy flows in one direction, but it is lost as heat. Matter is recycled in biogeochemical cycles**.** In the water cycle, water vapor condenses around dust particles in condensation, falls to earth as precipitation, is released from the surfaces of water bodies as evaporation, is released from land plants in transpiration, travels from the mountains to the ocean as runoff, is absorbed from the groundwater by plants, goes through the atmosphere as transportation, goes from the ground to the surface as infiltration, percolates from the surface to the groundwater, and finally flows through the groundwater. As most of the water is in the ocean, 25% is fresh, mostly in glaciers and ice caps. However, the ice is melting and evaporating.
Biogeochemical Cycles, and the Water Cycle Questions: Carbon, hydrogen, nitrogen, and oxygen are important for living things, and energy does not move in a cycle. Matter needs to be cycled so that the biosphere does not collapse without metabolic cycles, so it can be cycled through processes like decomposition and erosion. Carbon is found in all the major molecules of life. Water is essential for all life, and so is nitrogen as it is in DNA, RNA, amino acids, and proteins. We then labeled steps in the water cycle, and analyzed a model of it. The model showed how nature recycles water and stores it in the ocean, groundwater (in aquifers), glaciers, and surface water. When the air is highly polluted, water condenses around pollutants that enter the cycle. Transpiration, absorption, percolation, and evaporation filter out pollutants. Thus, it is essential to keep water free from pollutants.
Story of a Water Molecule…
Introduction to Carbon, and the Carbon Cycle: Matter is made of atoms, the smallest unit of matter that cannot be broken down by chemical means. Atoms are found as various elements, or pure substances that are made of only one kind of atom. A chemical bond is a force that joins atoms, and one form is a covalent bond which happens when two or more atoms share electrons to form a molecule. Organic compounds contain carbon atoms that are covalently bonded to other elements, and they can be carbohydrates, lipids, proteins, or nucleic acids. Carbohydrates are made of carbon, hydrogen, and oxygen at a ratio of 1:2:1, and they are a significant source of energy. A biogeochemical cycle is a closed cycle where paths of water, carbon, nitrogen, and phosphorus pass from the nonliving environment to organisms and back again. Thus, water, carbon, nitrogen, and phosphorus are reused. Photosynthesis removes carbon from the atmosphere and gives it to plants and eventually animals, and respiration, combustion, and erosion put it back. Carbon reservoirs are where carbon is stored, like in the ocean, rocks, fossil fuels, and living organisms. Bacteria fixes nitrogen so plants and animals can absorb it.
Biogeochemical Cycle Notes: Carbon Cycle: Carbon is the element of life, and it is 100 times more concentrated in the biosphere than in the earth. Carbon needs to be recycled for life to continue. It is found in the atmosphere, dissolved in water to make carbonic acid, in calcium carbonate rocks, in deposits of coal, petroleum, and natural gas, and in humus (dead organic matter). In the biosphere, it enters through photosynthesis or chemosynthesis and returns through cellular respiration, burning, and decay. Carbon dioxide levels in the atmosphere have risen severely over time, so uptake and return are not in balance.
What Contains Carbon and How Does it Move?: We identified which objects contain carbon. Then, we drew a simplified carbon cycle.
Carbon Cards (?)…
A Year in the Life of Earth’s CO2: The northern hemisphere has more land and people. The most carbon dioxide is in the environment in the northern hemisphere in the spring and early summer, and there is the least in the end of summer and through fall. It increases in the northern hemisphere in October and November and decreases in January and February. Most of the time, the most carbon dioxide comes from North America, East Asia, and West Europe. Africa, South America, and Australia tend to absorb carbon dioxide with their more plants and less human activity. Thus, atmospheric carbon dioxide tends to increase with more intense industrial human activity.
Duckweed Lab Conclusion PLAN: As we increased the salt concentration in the solution, the duckweed growth decreased. In the cup with the 30mM salt concentration, there were 11 fronds from the original 10 fronds by the 19th day. In the cup with the 50mM salt concentration, there were 14 fronds from the original 10 fronds by the 19th day. In the cup with the 60mM salt concentration, there were 13 fronds from the original 10 fronds by the 19th day. In the control cup with a 0mM salt concentration, there were 227 fronds from the original 10 fronds by the 19th day. By the end of the data collection, the fronds in the cups with salt were all white. The data shows that salt stunts duckweed growth. As duckweed grows and reproduces by increasing the number of fronds, we counted many fewer fronds in all of the cups with salt by the last day of experimentation than the fronds in the control group that had no salt. Since the increase in the number of fronds between the 30mM cup and the other cups was so minimal compared to the increase in the number of fronds in the control group, we found that any amount of salt vastly stunts duckweed growth, surprisingly contrary to our research and hypothesis. In addition, we found that the number of fronds interestingly peaked in the middle of our data collection for the 30mM and 50mM cups.
Carbon Cycle Summary: Carbon dioxide and methane are increasing in the atmosphere, but also carbon monoxide. Activities like burning fossil fuels and respiration release carbon, and most of these activities can be controlled by humans. Photosynthesis, phytoplankton, and rock formation remove carbon. Global carbon dioxide decreases from May to September due to increased photosynthesis and decreased fossil fuel burning. Atmospheric carbon dioxide photosynthesizes into organisms, and the ocean absorbs decomposing organisms with carbon, making fossil fuels from decomposed plants and animals. Carbon gets into cement through shells and corals. Over time, atmospheric carbon dioxide is increasing linearly. We should try to increase photosynthesis and decrease fossil fuel burning, overfarming, and overpopulation to reverse this increase in carbon.