biology EXAM #1 pt. 1 Flashcards
Science :
- the investigation of rational concepts that can be evaluated
Hypothesis :
a proposed explanation for an observed phenomenon
Theory :
- a hypothesis that is consistent with all available evidence
Biology :
Is the scientific study of life by observations and experimentation.
The study of life:
Extends from the microscope scale of molecules and cells to the global scale of the entire living planet
Biologists ask questions such as:
How does a single cell develop into an organism?
How does the human mind work?
How do living things interact in communities?
Life is :
recognized by what living things do
There are five unifying themes:
-Organization
-Information
-Energy and matter
-Interactions
-Evolution
The hierarchy of life:
Extends through many levels of biological organization
Order of biggest unit of structure to smallest
- Biosphere
- Ecosystems
- Communities
- Populations
- Organisms
- Organs and Organ systems
- Tissues
- Cells
- Organelles
- Molecules
The cell :
– An organism’s basic unit of structure and function
-Is the lowest level of organization that can perform all activities required for life
Every cell is enclosed:
enclosed by a membrane that regulates passage of materials between the cell and its environment
All cells share certain characteristics:
- They are all enclosed by a membrane
- They all use DNA as genetic information
There are two main forms of cells:
Eukaryotic
Prokaryotic
Eukaryotic cells:
Are subdivided by internal membranes into various membrane-enclosed organelles
-nucleus (contains DNA)
Prokaryotic cells:
Lack the kinds of membrane-enclosed organelles found in eukaryotic cells
-DNA (no nucleus)
Cells contain chromosomes made partly:
of DNA, the substance of genes
Which program the cells’ production of proteins and transmit information from parents to offspring
Each chromosome has:
one long DNA molecule with hundreds or thousands of genes
Genes :
encode:
units of?
-encode information for building the molecules synthesized within the cell
-units of inheritance
DNA controls:
controls the development and maintenance of organisms
Genes control:
process-
protein production indirectly.
DNA is transcribed into RNA, which is then translated into a protein
Gene expression:
is the process of converting information from gene to cellular product
Interactions between components that make up living organisms are:
components:-organs, tissues, cells, and molecules
are: crucial to their smooth operation
Cells are able to cooordinate:
coordinate various chemical pathways through a mechanism called feedback
In feedback regulation:
the output, or product of a process, regulates that very process
The most common form of regulation in living organisms is:
negative feedback, in which the response reduces the initial stimulus
A less common form of regulation is:
positive feedback, in which an end product speeds up its own production
Feedback is:
a regulatory motif common to life at all levels
An organism’s genome :
is its entire set of genetic instructions
The human genome and those of many other organisms :
have been sequenced
Genomics:
is the study of sets of genes within and between species
Proteomics:
is the study of whole sets of proteins encoded by the genome (known as proteomes)
The genomics approach depends on:
-“High-throughput” technology, which yields enormous amounts of data
-Bioinformatics, which is the use of computational tools to process a large volume of data
-Interdisciplinary research teams
Each organism:
Both organism and environment:
-Interacts with its environment
-Are affected by the interactions between them
The dynamics of any ecosystem include two major processes:
-Cycling of nutrients: materials acquired by plants eventually return to the soil
-The flow of energy: from sunlight to producers to consumers
All activities of life require:
-organisms to perform work, which depends on an energy source (the sun, other organisms…)
The exchange of energy between an organism and its surroundings
Often involves:
the transformation of one form of energy to another
Energy flows__________ through an ecosystem usually entering :
-one direction
-as sunlight and exiting as heat
Interactions between the components of the system ensure:
-This holds true equally well for components of :
smooth integration of all the parts
-an ecosystem and the molecules in a cell
At the ecosystem level, each organism interacts continuously :
These interactions may be:
with other organisms
- beneficial or harmful to one or both of the organisms
Organisms also interact continuously with __________________, and the environment is affected by:
-the physical factors in their environment
-the organisms living there
Over the past 150 years,
humans have greatly increased the burning of fossil fuels and the release of carbon dioxide (CO2) into the atmosphere
___________________ is just one aspect of climate change
-_________________ patterns are also shifting
-____________________ are occurring more often
-The resulting global warming
-Wind and precipitation
-Extreme weather events such as storms and droughts
As habitats deteriorate,
plant and animal species shift their ranges to more suitable locations
Populations of many species are:
shrinking in size or even disappearing
Evolution is the one idea:
that makes logical sense of everything we know about living organisms
The scientific explanation for both the unity and diversity of organisms is:
the concept that living organisms are modified descendants of common ancestors
Approximately #______ species have been identified and named to date, and __________ more are identified each year
-1.8 million
-thousands
Estimates of the total number of species that actually exist range from
10 million to over 100 million
Taxonomy:
Is the branch of biology that names and classifies species according to a system of broader and broader groups
Classifying Life:
- Species
- Genus
- Family
- Order
- Class
- Phylum
- Kingdom
- Domain
At the highest level, life is classified into three domains:
Bacteria
Archaea
Eukarya
Domain Bacteria and domain Archaea Consists of:
-once thought to be:
of prokaryotes
-Once thought to be the Monera kingdom
Domain Eukarya, the eukaryotes
Includes:
the various protist kingdoms (under work)and the kingdoms Plantae, Fungi, and Animalia
A striking unity underlies the diversity of life; for example:
DNA is the universal genetic language common to all organisms
Unity is evident in many features of cell structure
The history of life as documented by:
fossils and other evidence is the saga of a changing Earth, billions of years old
The evolutionary view of life
Came into sharp focus in:
1859 when Charles Darwin published On the Origin of Species by Natural Selection
Darwin made two main points:
-Species showed evidence of “descent with modification” from common ancestors
-“Natural selection” is the mechanism behind descent with modification
Darwin’s theory explained the :
duality of unity and diversity
Darwin observed that:
-Individuals in a population vary in their traits, many of which are heritable
-More offspring are produced than survive, and competition is inevitable
-Species generally suit their environment
Darwin inferred that:
-Individuals with traits that are best suited to their environment are more likely to survive and reproduce
-Over time, more individuals in a population will have the advantageous traits
Evolution occurs as the unequal reproductive success of individuals ultimately leads to
adaptation to their environment
NATURAL SELECTION
The natural environment “selects” for the propagation of beneficial traits
Natural selection results in :
For example,
-the adaptation of organisms to their environment
-bat wings are an example of adaptation
The Origin of Species articulated two main points:
-Descent with modification
-Natural selection
Darwin proposed natural selection :
As the mechanism for evolutionary adaptation of populations to their environments
Natural selection is the evolutionary process that occurs when
When a population’s heritable variations (or genetic makeup) are exposed to environmental factors that favor the reproductive success of some individuals over others
Many related organisms
Have:
very similar anatomical features, adapted for their specific ways of life
kinship:
For example,
-________ provide additional evidence of anatomical unity from descent with modification
-Connect life’s “unity in diversity” to Darwin’s concept of “descent with modification”
· the forelimb of the bat, human, and horse and the whale flipper all share a common skeletal architecture
-Fossils
Darwin proposed that natural selection Could enable:
an ancestral species to “split” into two or more descendant species, resulting in a “tree of life”
Each species is on twig of a:
All of life is:
-branching tree of life extending back in time through ancestral species more and more remote
-connected through its long evolutionary history
Scientists use a process of inquiry that includes:
making observations, forming logical hypotheses, and testing them
At the heart of science is _____: ___
inquiry:
A search for information and explanation, often focusing on specific questions
Biology blends two main processes of scientific inquiry:
-Discovery science
-Hypothesis-based science
Discovery science: define
Describes natural structures and processes as accurately as possible through careful observation and analysis of data
Biology begins with:
Observations can reveal:
careful observation
valuable information about the natural world
Biologists also rely heavily
They build on the foundation of:
Identifying relevant publications is easier than in the past, thanks to
on the published contributions of fellow scientists
of existing knowledge
indexed and searchable electronic databases
Data:
-are…
-can be…
-Are recorded observations
-Can be quantitative or qualitative
In inductive reasoning:
-Scientists derive
-What is fundamental to our understanding of nature:
-generalizations based on a large number of specific observations
-Careful observations and data analyses, along with generalizations reached by induction,
Inductive reasoning draws conclusions through :
-Repeating _____________ can lead to ______________
For example, “_____________________”
-the logical process of induction
-specific observations
-important generalizations
-the sun always rises in the east
In science, inquiry that asks specific questions usually involves the proposing and testing of hypothetical explanations, or hypotheses:
a tentative answer to a well-framed question, an explanation on trial. It is based on observations and assumptions, that lead to testable predictions.
Makes predictions that can be tested by making additional observations or by performing experiments
In deductive reasoning (phrase):
-The logic flows from the
-“If…then…”
-the general to the specific
Deductive reasoning uses:
Initial observations may give rise to
general premises to make specific predictions
-multiple hypotheses
We can never prove that a hypothesis is true, but testing it in many ways with different sorts of data can increase our confidence in it tremendously
LEE VARIAS VECES
If a hypothesis is correct:
Then we can expect a particular outcome
A scientific hypothesis must have two important qualities:
It must be testable
It must be falsifiable
Supernatural and religious explanations are outside the bounds of science
LEELO
The scientific method is an
Is an idealized process of inquiry
Very few scientific inquiries:
____________ may be necessary partway through the process
In other cases, observations may be too puzzling to prompt _____ ______, until further studies are complete
Adhere to the “textbook” scientific method
Backtracking
well-defined questions
TESTING IDEAS
-Forming hypothesis
-predicting results
-doing experiments or making observations
-gathering data
-analyzing results
INTERPRETING RESULTS DATA MAY
-support hypothesis
-contradict hypothesis
-inspire a revised or new hypothesis
EXPLORATION AND DISCOVERY
-observing nature
-asking questions
-reading the scientific literature
SOCIETAL BENEFITS OR OUTCOMES
-developing technology
-informing policy
-solving problems
-building knowledge
COMMUNITY ANALYSIS AND FEEDBACK
-feedback and peer review
-replications of findings
-publication consensus building
In mimicry:
A harmless species resembles a harmful species
Mimicry in king snakes is examined
The hypothesis predicts that:
predators in non–coral snake areas will attack king snakes more frequently than will predators that live where coral snakes are present
To test this mimicry hypothesis
Researchers made:
hundreds of artificial snakes, an experimental group resembling king snakes and a control group of plain brown snakes
After a given period of time
The researchers collected:
data that fit a key prediction
Experiments must be designed to test
The effect of one variable by testing control groups and experimental groups in a way that cancels the effects of unwanted variables
lee
In a controlled experiment,
an experimental group (the non-camouflaged mice in this case) is compared with a control group (the camouflaged mice)
Experimental variables are:
The independent variable:
The dependent variable is:
-features or quantities that vary in an experiment
- is the one that is manipulated by the researchers
- the one predicted to be affected in response
Science cannot address supernatural phenomena Because:
-hypotheses must be testable and falsifiable and experimental results must be repeatable
A scientific theory
-generates
-supported by
-Is broad in scope
-Generates new hypotheses
-Supported by a large body of evidence in comparison to a hypothesis
_______________________
Help us understand scientific phenomena and make predictions
Models of ideas, structures, and processes
Science is a ______ ______
Characterized by both :
-social activity
-cooperation and competition
Most scientists work in _____, which often include graduate and undergraduate students
-teams
___ _______ is important in order to share results through:
-Good communication
seminars, publications, and websites
Technology
Applies:
scientific knowledge for some specific purpose
Many important inventions have occurred where :
For example, the printing press relied on innovations:
-different cultures and ideas mix
-from China (paper and ink) and Europe (mass production in mills)
Science benefits from:
diverse views from different racial and ethnic groups, and from both women and men
The more voices heard, the more
robust, valuable, and productive the scientific interchange
Research papers are not published until :
vetted by colleagues in the “peer review” process
Scientists check each other’s claims by:
If experimental results are not repeatable,:
It is not unusual for:
- performing similar experiments
- the original claim will have to be revised
- different scientists to work on the same research question
Scientists cooperate by
Biologists approach interesting questions from :
sharing data about model organisms (for example, the fruit fly Drosophila melanogaster)
*There are several other popular model organisms as well
-different angles
The goal of science is to
understand natural phenomena
The goal of technology is
to apply scientific knowledge for some specific purpose
Science and technology are
interdependent (dependent on each other)
The combination of _______ __ ______ can have dramatic effects on society
-For example,
-science and technology
-the discovery of DNA by James Watson and Francis Crick allowed for advances in DNA technology such as testing for hereditary diseases
Debates on technology center more on :
“should we do it” than “can we do it”
Ethical issues that arise from new technology can have as much to do with ____ as with _____
politics, economics, and cultural values as with science and technology
DOMAIN BACTERIA
Bacteria are the most diverse and widespread prokaryotes and are divided into multiple kingdoms.
DOMAIN EUKARYA: -kingdoms
- protists: many kingdoms, unicellular eukaryotes and siple multicellular relatives. scientists are debating how to split protists into kingdoms that work.
- Kingdom Plantae: multucellular eukaryotes that carry out photosynthesis, conversion of light energy into food.
- Kingdom Fungi: is defined in part by the nutritional mode of its members which absorb nutrients after decomposing organic material
- Kingdom Animalia: multicellular eukaryotes that ingest other organisms
DOMAIN ARCHAEA
Archaea are prokaryotes that live in Earth’s extreme environments. Includes multiple kingdoms.
The molecular structure of DNA
Accounts for its
information-rich nature
DNA double helix:
each atom in a segment of DNA. Made up of two long chains of building blocks called nucleotides
A DNA
molecule takes the three-dimensional
form of a double helix.
Single strand of DNA.
These geometric shapes and letters are simple symbols for the nucleotides in a small section of one chain of a DNA molecule.
Genetic information is encoded in specific sequences of the four types of nucleotides (their names are abbreviated here as A, T, C, and G).
_____________ vary widely in nature, sometimes even between members of the same species
-Color patterns of animals
Two populations of mice of the same species (Peromyscus polionotus) but with different color patterns reside in
The two types of mice match the coloration of
Natural predators of these mice are all
Francis Bertody Sumner hypothesized that the color patterns had evolved as
different environments
-their habitats
- visual hunters
-adaptations that protect the mice from predators
CASE STUDY OF MICE
The researchers predicted that
They built
The data fit the
mice that did not match their habitat would be preyed on more heavily than mice that did match the surroundings
models of mice, painted them to match one of the surroundings, and placed equal numbers of each type of model in each habitat
key prediction of the camouflage hypothesis
