Biology 1710 Foundations of Biology PDF

Biology 1710 Evolution and the Foundations of Biology Dr. Ann Price Fall 2024 What is Science? The systematic study of the structure and behavior of the physical and natural world and its phenomena through observation and experiment Science is both...

Biology 1710 Evolution and the Foundations of Biology Dr. Ann Price Fall 2024 What is Science? The systematic study of the structure and behavior of the physical and natural world and its phenomena through observation and experiment Science is both a body of knowledge and a process. What is Biology? Biology is the scientific study of life Biologists ask questions such as How does life work? How does a single cell develop into an organism? How does the human mind function? How do different forms of life in a forest interact? What is life? Basic Properties of life Order Maintains homeostasis Consumes energy/nutrients Grows/Develops Responds to stimuli/environment Reproduces Adaptation Evolve Concept 1.1: The Study of Life Reveals Unifying Themes To organize and make sense of all the information encountered in biology, focus on a few big ideas These unifying themes help to organize biological information: Organization Information Energy and matter Interactions Evolution  Theme: New Properties Emerge at Successive Levels of Biological Organization 7 Tissues 1 The Biosphere Life can be 6 Organs studied at different 2 Ecosystems 50 µm levels, from Cell 10 µm 8 Cells molecules to the entire 10 Molecules living planet Atoms 3 Communities Chlorophyll molecule 9 Organelles 5 Organisms 1 µm Chloroplast 4 Populations 11 Atoms and subatomic particles Figure 1.3  Emergent Properties Emergent properties result from the arrangement and interaction of parts within a system Emergent properties characterize nonbiological entities as well For example, a functioning bicycle emerges only when all of the necessary parts connect in the correct way Classifying Organisms Grouping “like” organisms together allows us to study biological emergent properties Figure 1.12 The Three Domains of Life (a) Domain Bacteria (b) Domain Archaea 2 µm 2 µm Bacteria are the most diverse and widespread prokaryotes and are Domain Archaea includes multiple kingdoms. Some of the now classified into multiple kingdoms. Each rod-shaped structure prokaryotes known as archaea live in Earth’s extreme in this photo is a bacterial cell. environments, such as salty lakes and boiling hot springs. Each round structure in this photo is an archaeal cell. (c) Domain Eukarya Kingdom Animalia Consists of multicellular eukaryotes that ingest other organisms. 100 µm Kingdom Plantae (plants) consists of multicellular eukaryotes that carry out photosynthesis, the conversion of light energy to the chemical energy in food. Most plant species live on land. Protists are mostly unicellular eukaryotes and some relatively simple multicellular Kingdom Fungi relatives. Pictured is characterized here is an assortment in part by the of protists inhabiting nutritional mode of its members (such as this mushroom), pond water. Scientists are currently debating how to classify protists which absorb nutrients from outside their bodies in a way that accurately reflects their evolutionary relationships.  Structure and Function At each level of the biological hierarchy, we find a correlation between structure and function Analyzing a biological structure can give clues about what it does and how it works Figure 1.4 Contrasting Eukaryotic and Prokaryotic Cells in Size and Complexity Why study biology? Scientific study of life and living organisms What is life? How can we protect it? How and why does it change over time? Governs our existence What happens Why it happens When it happens How these things are controlled Why study biology? Opens the door to a wide variety of careers Research Medical research Pharmaceutical research Ecology Wildlife Agriculture Medicine Teaching Interdisciplinary careers like Bioinformatics and Bioengineering Why study biology? Biology will be THE pivotal science of the 21st century It will do for the 21st century what physics did for the 19th and chemistry did for the 20th Inductive vs. Deductive reasoning Inductive Draws conclusions based on evidence Make observations  Develop hypothesis Deductive Uses a general principle or law to predict results Hypothesis  Test  Analyze Inductive vs. Deductive reasoning You hear a gunshot and walk into a room to find Bob standing over a dead body holding a smoking gun. Do you induce or deduce he is a murderer? A. Induce B. Deduce  Make Observations Observations Refers to data gathered informally from personal experience, previous experiments, or from other scientists in presentations, articles, etc. It is the information that inspires the thought processes leading to hypotheses. Not always as easy as it sounds Sometimes things are hard to see (small, rare) Sometimes so commonplace we don’t even notice them Research In order to make an educated guess, you must be educated. Find out what is known Find out what is not known Find out what is guessed at Journals Scientific books Textbooks  Hypothesis Make Observations Research Do some background research This is an explanation Hypothesis as to the cause of some relationship. It is a suggestion as to the mechanism underlying some occurrence Must be testable!  Predictions Make Observations Predictions are the proposed outcomes of experiments if a Hypothesis particular hypothesis is correct Predictions  Controlled Make Experiment Observations In this type of an experiment, the experimenter manipulates a variable (the experimental, manipulated, or independent Hypothesis variable). There are at least two groups. The experimental group, which has had some specific manipulation of the variable of interest, The control group, which is treated exactly like the experimental group in every way possible except for a lack of manipulation of the variable of Experiment Predictions interest. Correlational/Observational Make /Descriptive Experiment Observations In this type of an experiment, the experimenter cannot manipulate a variable. Therefore s/he measures and examines differences among subjects or Hypothesis naturally occurring groups. Because one is not manipulating the variable, this type of experiment does not provide as strong a test of a hypothesis. Not all information is gathered in science through controlled experiments, or even experiments at all. This is an example. Experiment Predictions Sanjay Kulkarni, Cowbirds in Love  Make Scientific Observations Method Does the data support the hypothesis? Analyze Data No Hypothesis Experiment Predictions  Scientific Adjust, refine or Method reject your hypothesis Analyze Data No Hypothesis Much research time is spent here Experiment Predictions  Populations of Make mice have Observations very different Observations fur color  Populations of Research: The coat colors are not Hypothesis Make mice have Observations very different evenly spread by are clustered in fur color different regions Research into the topic gives the Natural scientist a clue selection favors Hypothesis animals that blend into their backgrounds  Populations of Research: The coat colors are not Predictions Make mice have Observations very different evenly spread by are clustered in fur color different regions Predictions are the proposed outcomes of Natural selection favors experiments if a Hypothesis animals that particular hypothesis is blend into their correct backgrounds Animals that match their Predictionswill environments have higher survival rates Controlled Populations Animals getof Make mice have fat, Experiment Observations very different plants do not fur color If plants Naturalhad these proteins, selection favors Analyze Data Hypothesis they would animals that make and blend into store their fat (oils) backgrounds Place mice models in each Expression Animals thatof Fat Specific match Protein their 27 environment Experiment and count will induce lipid environments will accumulation have higherin predator plantsrates survival attacks  Figure 1.21 Inquiry: Does Camouflage Affect Predation Rates on Two Populations of Mice? Beach habitat Inland habitat 100 attacked models Percentage of 50 0 Light models Dark models Light models Dark models Camouflaged Non-camouflaged Non-camouflaged Camouflaged (control) (experimental) (experimental) (control) Facts, Hypotheses, Theories and Laws A FACT is a basic statement established by experiment or observation. All facts are true under the specific conditions of the observation. A HYPOTHESIS is a tentative or proposed explanation that is TESTABLE A (scientific) THEORY is an explanation so thoroughly tested and well supported that no new data is likely to alter it A LAW is an explanation for how nature will behave under certain conditions, frequently written as an equation. A Belief is a statement that is not scientifically provable. Beliefs may or may not be correct but they are outside the realm of science to test.  Important Considerations in Science Scientists avoid terminology such as "Proven" or "Unproven". They expect explanations to change as researchers gather more evidence and formulate new theories to better explain events. Observations lead to testable hypotheses (causal explanations based on previous observations or knowledge). Systematic testing of hypotheses generates results that are evaluated in a public forum of scientists. Hypotheses generate predictions Experiments generate results Results are compared to predictions as evidence for/against hypotheses The best practice of critical thinking in science is to look for the simplest, most parsimonious explanation  Graphing Visual representations of your data help people better understand what your results mean and lead to a better understanding of the impact of your experiments MmFSP27 increases the size and numbers of LDs in Leaf Tissue Price et al., 2017 Graphing a controlled experiment R2 Value How reliable is your trend? Mint Beats.com Experimental Variables and Controls (1 of 2) A controlled experiment compares an experimental group (the non-camouflaged mice) with a control group (the camouflaged mice) The factor that is manipulated and the effect of the factor on the system are both experimental variables The factor manipulated by the researchers—color—is called the independent variable The effect of the manipulated factor—amount of predation—is called the dependent variable  Correlational Experiments Provide weaker support than controlled, but are sometimes the only option No other earth for global warming studies Can’t withhold services from people. There are clear, ethical concerns with experimenting on people However, correlation does not prove causation! Correlation and Causation Significance is measured by a P Value P Value = Probability Value That is, the probability that the trend you are seeing is due to random chance. The lower the p value, the greater the statistical significance P values are generally significant < 0.05 or < 0.01 depending on circumstances Standard Deviation How much variance is in a set of data Mathworks.com TD Ameritrade  Parametric Versus Nonparametric Tests In the literal meaning of the terms, a parametric statistical test is one that makes assumptions about the parameters (defining properties) of the population distribution(s) from which one's data are drawn, while a non-parametric test is one that makes no such assumptions. Due to smallish sample sizes, your data will probably not meet all the assumptions for a parametric test, but for the sake of simplicity, and for the sake of time, we will use the parametric tests for this class Just remember that really good statistics is in reality far more complicated that what we are going to do Height of human beings Normal distribution (continuous probability distribution) graphed as a bell curve Height of human beings is a parametric distribution The parameter μ (mu) is the mean or expectation of the distribution (and also its median and mode), while the parameter σ (sigma) is its standard deviation. What about color? Favorite color is not a parametric distribution Peer Review Experts in the field judge whether the work is sound, well thought out, appropriately and sufficiently tested, conclusions supported FIGURE 1.8 The presence of a membrane-enclosed nucleus is a characteristic of _____________. A. prokaryotic cells B. eukaryotic cells C. living organisms D. bacteria E. viruses "The sanctity of life doesn’t seem to apply to cancer cells, does it? You rarely see a bumper sticker that says: “Save the tumors.” Or “I brake for advanced melanoma.” No, viruses, mold, mildew, maggots, fungus, weeds, E. Coli bacteria, the crabs. Nothing sacred about those things. So at best the sanctity of life is kind of a selective thing. We get to choose which forms of life we feel are sacred, and we get to kill the rest. Pretty neat deal, huh? You know how we got it? We made the whole f*****g thing up!"..... -