Scientific Method: Hypotheses and Theory

Nature of Science and Scientific Method

• The scientific method provides a way to understand nature
• The scientific method is flexible
• Incorrect ideas or hypotheses can be changed based on evidence
• Science explains the natural world and its phenomena
• Science is open to revision and never totally proven
• Ideas are subjected to change and reliable, grounded in substantial evidence
• Science considers testable ideas that can be tested through experimentation
• Testing and evidence are science's basis
• Evidence can be found or refuted by various individuals on the same topic
• Science relies on the discoveries of the community as a whole
• Discoveries form the basis of future research
• Science is continuous, generating new hypotheses
• Ideas need evidence against them to be refuted
• Instead of proving ideas right they are proven wrong
• Ideas, but not data, are subject to change, as science is self-correcting

Hypothesis vs. Theory

• Hypotheses are informed inferences with the goal of explaining phenomena and making observation predictions
• Theories are statements explaining multiple phenomena, that make predictions, and that are refuted and modified
• Predictions are a series of observations expected when a proposed idea is correct

Experimental Design Elements

• Controls are groups in experiments not subjected to variables - used to determine the experiment's effectiveness compared to groups with variables
• Constant conditions are conditions that remain the same; they allow for accurate comparison of the variable effects
• Repeatability ensures tests aren't drawing data from sampling errors
• Repeatability makes experiments more accurate
• Placebos mimic a medicine's physical taste and appearance without having an actual effect
• Placebos enable observation of the actual effects of a drug
• The dependent variable is the result measured in an experiment
• The independent variable, or the treatment, stays continuous throughout the experiment and isn’t affected by the independent variable
• Continuous data are a curve, scattered data, scatter plot sort fo
• Categorical data are data categorized based on treatment or type of experiment

Valid Scientific Statement Characteristics

• Falsifiable - can be proven wrong with evidence
• Focuses on and explains the natural world
• Uses testable ideas
• Relies on evidence
• Involves scientific communities
• Leads to ongoing research
• Benefits from scientific behavior

Intelligent Design vs. Evolution

• Intelligent design - the belief that a higher, more intelligent being created the natural world
• Evolution involves changes in traits and characteristics of populations over time
• Evolution is grounded in significant evidence
• Evolution is tested with fossils and carbon dating
• Evolution can also lead to further research
• Evolution aims to explain how species change over time, as well as their common ancestors
• Evolution includes a community of scientists
• Evolution is scientific according to the guidelines

Scientific Nomenclature

• Scientific names are written as "Genus species"
• "Genus species" are italicized when typed and underlined when handwritten
• The full name - Genus species - must be used first, but can be shortened to G.species

Definitions

• Evidence is scientific observations that refute or support ideas
• Evidence supports, but never fully proves, an idea
• Belief is an idea in which one has a strong conviction
• Acceptance involves acknowledging that extensive evidence has been presented in favor of the idea
• Function in biology refers to what tools do, structures and what behaviors of living things have

Patterns vs. Mechanisms

• Patterns are what one observes to occur in nature
• Mechanisms explain how observations occur in nature

Null vs. Alternative Hypothesis

• Null hypotheses state that there is no difference in experimental results between the control group and the experimental groups exposed to variables
• Differences are considered to be due to sampling error or uncertainty
• Alternative hypotheses state that if enough evidence exists to reject the null hypotheses, it is the original expectation of results, or the anticipated result for the experiment

Correlation vs. Causation

• Correlation is the relationship between two or more ideas, organisms, and/or events
• Causation is the cause of an event or an idea

Cell Theory

• All living things are made up of cells
• Cells are the smallest basic unit of life (pattern)
• All cells come from pre-existing cells (mechanism)

Theory of Evolution by Natural Selection

• Theory says all organisms share a common ancestor (pattern)
• Allele frequencies change over time (mechanism)
• Changes lead to alterations in characteristics of a population over time

Theories to Know

• Chromosomal Theory of Inheritance
• Pseudoscience - beliefs mistaken as scientifically grounded
• Anecdotal evidence - evidence from personal experience or observation

History of Evolutionary Thought

• Lamarck proposed that species change over time, a concept Darwin used in his own claims
• Darwin disagreed with Lamarck's hypothesis of inheritance of acquired traits and that the environment physically changes genotypes, thus creating new phenotypes
• Darwin agreed that populations and species change over time, but emphasized that genetic variation is important

Use/Disuse and Inheritance of Acquired Traits

• Lamarck’s hypothesis stated that individuals acquire survival traits from the environment and pass the traits down to their offspring
• Rejected, because an individual's genotype can’t be physically changed by the environment; only mutation creates new genotypes/phenotypes
• Phenotype changes from environmental factors do not change the DNA or genotype; genotypes don’t always affect phenotypes

Gradualism, Uniformitarianism and Population Growth

• Gradualism states: Earth’s features result from slow natural processes over time
• Gradualism influenced Darwin - stressed past as key to future events
• Uniformitarianism states: Geological processes that occurred in the past are still the same as now
• Malthus' writing described that less members will survive with maturity
• Malthus' writing helped Darwin understand why some individuals survive and some don't, which in turn made him realize that individuals with heritable traits are more able to survive and reproduce

Darwin’s Theory

• Observation 1: Species and populations grow exponentially
• Observation 2: After a certain size the population size remains stable
• Observation 3: Natural resources for a population are limited
• Inference 1: Because of limits, not all offspring mature due to competition for resources
• Observation 4: Individuals of the same species vary genetically
• Observation 5: Majority of traits and characteristics can be passed down from generation to generation.
• Inference 2: Some individuals survive and reproduce better than others due to beneficial traits = differential survival
• Inference 3: Differential survival isn’t random; some traits are better in an environment & allow for more survival/reproduction frequency in the population

Definitions

• Evolution is a change in the traits and characteristics in a population over time
• Microevolution consists of changes across generations and changes in gene frequency over a short period of time
• Macroevolution is the evolution of large groups over a long period of time
• Natural selection involves what the individual survives to reproduce
• Traits that allow the individual to have higher fitness mean that the species is selected for by nature so causing disadvantage ones to lower in frequency
• Heritable traits are able to be passed to generations
• A population is the same species living in the same region
• Typological VS population: that Typological ignores variation within the same species, and that population focuses on variation
• Scala- Some Species have less perfection then other and their were believes of a scale

Evidence for Evolution

• Phylogenetic trees show the evolutionary relationship between organisms
• Branches are taxa
• Nodes are the most recent common ancestor
• Traits are shared together by organisms succeeding possessing them
• Fossilization preserves past organisms
• The fossil record consists of found fossils
• The organism must first decay
• It must be buried fast
• No bacteria is present
• No O2 to sustain
• Relative dating consists of younger strata above layers
• Relative dating is also lower to go more older
• Depth of fossil that determines realtive dating
• Relative dating is also in different areas of strata
• Radiometric dating is carboon dating

Radioactive Decay

• What is rate
• Atoms from daughter and parents
• Rations of what happens to around
• Has bias to already dieing
• Habiata bias where lives settle
• Taxoomic
• Tissues that withstand well
• Abundance bias for common
• Temporal for recent is more common and closer
• The change of fossil being there is low
• Continents of continents moove the time
• New species made because broke
• Catastrophic is hard
• Low allele freq

Extinctions

Mass

• Species the earth
• Darain say evolution
• Some exist so they do
• Darwin says ok
• So if 60 exist
• Hard times make zero

Distguish

Convergent is that homolgy does

• In a tree
• How is it related
• How does the shift
• C5. Explain how the fossil record* (including transitional fossils), artificial selection, biogeography, and homology (including vestigial traits and the universality of the genetic code), provide evidence for evolution (i.e., support hypotheses of common ancestry/descent with modification). [Knowledge, Comprehension]
• a) Fossil Record:*

Gives Fossils time in life

• Lower fossils
• Succession
• Found fossils similar same the success
• b) Artificial Selection:*

Artifical provding by

• Those for trates
• These see increase with generations
• Support and c) Biogeogrpahy

Geogrpahy distribution To each have some live in same one there

• Common there
• Then closer that that relation Evolutionary same of how differ or relation how to common the a

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