Exam 1 B&E

Life

The ability of an entity comprised of one or more cells to conduct metabolism, sense changes in the environment and respond, entities to evolve.

Metabolism

The chemical reactions and other processes that enable organisms to take in resources and process them in ways that make growth and reproduction possible

Organism

A living thing—a being or individual

Evolution

A change in the allele frequencies in a population

Fossil Record

Any trace of an organism that lived in the past

Adaptation

A heritable trait that increases the ability to survive and reproduce in a particular environment

Independent variable

(also known as the predictor or explanatory variable) a variable whose value does not depend on the value of another variable. common examples include treatment groups in an experimental study or time

Dependent variable

(also known as the response variable) a measured quantity whose value depends on the value of another variable

Discrete variable

A quantity that can only take certain, discrete values

Continuous variable

a quantity that can take a continous range of values

Scatterplot

a type of graph where individual datapoints from two continouse variables are plotted to assess wheter the variables are correlated in any way

Histogram

a type of graph where a range of possible values is plotted along the x-axis and the frequency of datapoints in each interval in the range is plotted on the y-axis

Science

a human endeavor based on asking questions about the natural and physical world and answering them with measurable, verifiable evidence

Pseudoscience

a tradition that tries to explain or predict natural and physical phenomena but 1) does not rely on measurable, verifiable evidence, and 2) invokes mysterious or unnamed mechanisms rather than known physical mechanisms.

Hypothesis

a proposed explanation for something that researchers have observed

Prediction

a statement of an outcome that should occur if a hypothesis is “correct”

Null Hypothesis

a hypothesis that represents the “not” or “no-effect” contrast to the hypothesis being tested

Treatment (or experimental) Group

a group that experiences experimental conditions that conform to the mechanism proposed in the hypothesis

Control Group

a comparison group that represent the normal or no-treatment condition to contrast with groups that experience experimental maniupulation

Controlled Conditions

aspects of an experimental design that are used in both control and experimental treatments to eliminate bias among treatments and reduce influence from confounding factors

Outcome Variable

the variable that is measured in an experimental or observational study. it represents a quantity that is relevant to the hypothesis being tested.

Extinction

the demise of a species, meaning that no individuals of that species are still alive

Mass Extinction

an event where at least 60% of the species currently alive disappear in less than one million years

Adaptive Radiation

The rapid diversification of a lineage into a large number of species, each with adaptations that allow them to exploit different resources and habits

Niche

the range of resources and environments that a species uses

Monophyletic Group

An ancestor and all of its descendants

Relative Dating

assigning younger-to-older ages to rocks based on their positioning relative to each other

Absolute Dating

assigning chronological ages to rocks using data on 1) the decay rate of a specific radioactive isotope, and 2) the relative amounts of that isotope and the element produce when it decays

Evo-devo (evolutionary developmental biology)

a research field focused on understanding the genetic and molecular mechanisms responsible for evolutionary change—especially the origin of novel traits

Background Extinction Rate

the normal, long-term average at which species go extinct over time, outside of mass extinction events

DNA

a molecule that stores hereditary information in code form

Gene

segments of DNA that contain the information that molecular machines use to make a product—an RNA or protein—that functions in the organism

Mutation

any change in DNA. mutations create new alleles

Allele

versions of a gene. for example, if the product of a certain human gene affects hair color, one allele may lead to redder hair while another allele leads to browner hair. different alleles have different variations of the coded information in the gene

Genotype

a listing of the alleles present in an individual

Phenotype

What an individual looks or acts like

Fitness

the ability to produce offspring

Directional Selection

natural selection that favors an extreme phenotype

Stabilizing Selection

natural selection that favors the average phenotype in the population and acts against extreme phenotypes

Artificial Selection

when human actively and consciously select which individuals will be the parents of the next generation

Paradigm

your worldview or theoretical framework that shapes how we think, act, and understand the world

1859

the year that Charlies Darwin came out with his book, The Origin of Species

Popper

The scientist that came up with the idea of scientific theories are falsifiable. Genuine scientific theories, by making definite predictions, rule out range of observable states.

Deductive Reasoning

Given a premise (A), you form a logical conclusion (B)

Inductive Reasoning

Inferring a general principle (B) from a body of knowledge (A)

Abductive Reasoning

Observe something and seek simplest explanation

Occan’s razor

When you have more than one explanation, the simplest explanation is to be preferred

Paradigm Shift

We have a great theory, Our model or theory no longer seems to explain as well as it once did when we did not know as much. Scientific field reaches crisis. New hypotheses are proposed and tested and new theories formulated. Return to “normal science”

Things required before developing a theory of evolution

• New taxa can appear

• Importance of variation

• Concept of deep time

• Notion of transformation

• Mechanism of evolution

New taxa

newly discovered and officially named groups or categories of organisms

Why is variation important?

provides raw material that allows population to adapt to changing environments and survive over time.

What is deep time?

The concept of geological time spanning billions of years, vastly exceeding the scale of human experience.

What is the notion of transformation?

the fundamental, system-wide reorganization across technological, economic, and social factors that targets the root causes of nature’s decline rather than just its superficial symptoms.

Linnaeus

Created the field of taxonomy. Hierarchy. Varieties within species might be formed due to different environmental conditions. Some species within a genus might arise from natural causes, such as hybridization (new species can appear)

Taxonomy

the science of classifying and naming groups of organisms

Lamarck (1744-1829)

Created the Theory of Acquired Characteristics, common beliefs at time that he supported and applies to species. heritable effects of use and disuse. Most significant pre-Darwinian evolutionary hypothesis

Theory of Gradualism

the earth has changed slowly through time

Theory of Uniformitarianism

processes that occur today are the same that occurred in the past

Malthus

Wrote an essay on population growth that inspired Darwin’s idea of evolutionary mechanism called natural selection

Homology

Inherited from a common ancestor. Similar in form, but may not be similar in function. Guiding concept in biomedical research

Comparative Anatomy

compare organisms to see how are they similar and how they are different

Vestigial Structures

appear to have no function

Molecular Support for Evolution

All life shares some proteins in common

Transitional fossils

implies not only a beginning but a goal. Extant species are still evolving, so everything is “transitional”

Mechanisms of Evolution

• Genetic Mutation

• Gene Flow

• Genetic Drift

• Natural Selection

Central Dogma

Genetic information flows in one direction: DNA to RNA to protein

How natural selection works?

• Mutation produces new alleles

• Variation in heritable traits

• Differential reproduction due to trait

• Advantageous trait becomes more common in the population