chapter 1 - biology: exploring life

biology

the scientific study of life

what is life?

there are seven properties that make up life:

1. order

2. response to the environment

3. reproduction

4. growth and development

5. regulation

6. energy processing

7. evolutionary adaptation

   *the cell is the structural and fuctional unit of life

order

hierarchical organization seen in living systems

• life is characterized by highly ordered structures

  • each structure influence the other as that interaction at any level will affect subsequent levels

  • ex. sickle cell (abnormal structure)

response to the envrionment

reactors activated by stimuli

• all organisms respond to environmental stimuli

  • ex. cochlear in the ear, fly landing on a venus flytrap

reproduction

organisms reproduce their own kind

growth and development (over time)

inherited information encoded in DNA controls the patter of growth and development of all organisms

regulation

to maintain an optimal environment

• organisms have regulatory mechanisms that maintain a beneficial internal environment (range)

  • ex. lizard sunbathing to increase body temperature on cold mornings

energy processing

transforming energy

• organisms take in energy and use it to power all their activities

  *universe has a tendency to become more disorganized

  • ex. water evaporating (changing states)

evolutionary adaptation

change in inhabitable traits

• adaptations evolve over countless generations as individuals with heritable traits are best suited to their environment have greater reproductive success

taxonomy

organizing and classifying organisms

hierarchy mnemonic

D - domain

K - kingdom

P - phylum

C - class

O - order

F - family

G - genus

S - species

domains

3 higher levels in which life can be organized into: domain bacteria, domain archaea, domain eukarya

• debates in divisions occur among biologists, however, there is consensus that life can be organized into the highest level, domains

domain bacteria

diverse and widespread group of bacteria

• consists of microscopic organisms with simple cells

domain archaea

lives in earth’s extreme environments (salty lakes, boiling hot springs)

• consists of microscopic organisms with simple cells

domain eukarya

organisms with more complex cells (eukaryotes)

• protists, kingdom plante, kingdom fungi, kingdom animalia (all kingdoms except protists are organized by what they eat)

protists

multiple kingdoms in which consists of a diverse collection of mostly single-celled organisms

• biologists are accessing how to group the protists to reflect their evolutionary relationships

• currently a mess and organisms are closer to other kingdoms in the domain

kingdom plante

consists of plants

• produce their own food by photosynthesis

kingdom fungi

diverse group whose members mostly decomposes organic wastes and absorb the nutrients into their cells

kingdom animalia

animals

• obtain food by eating other organisms

  • humans belong in this kingdom

emergent properties

in life’s hierarchy of organization, new properties emerge at each level

• results from the specific arrangement and interactions amoong component parts

biosphere

all life on earth and the places where life exists

• these places include most regions of land, bodies of water, and the lower atmosphere

ecosystem

all the organisms in a particular area, as well as the physical components with which life interact

• ex. soil, water, and light

community

all the organisms in a ecosystem

population

all the individuals of a particular species living a community

organism

an individual living thing

organs and organ systems

body parts that perform a specific function

• several organs may cooperate in an organ system

tissue

a group of similar cells performing a specific function

• an organ is composed of several different tissues

cell

the fundamental and structural functional unit of life

• the property of life emerges at the level of the cell

organelle

a membrane-enclosed functional structure in a cell

• the nucleus is an organelle that encloses a cell’s DNA, its genetic instructions

molecules

a chemical structure consisting of two or more units of atoms

• strong and transmitting hereditary information are properties that emerge from the arrangement of atoms in a molecule of DNA

what is science?

way of knowing: an approach to understanding the natural world

• uses an evidence-based process of inquiry to investigate the natural world

data

recorded observations

• the eurdence on which scientific inquiry is based

  • qualitative and quantitative

qualitative data

non-numeric information that describes qualities or characteristics (descriptions)

quantitative data

frequency and duration of specific behaviors (numerical measurements)

hypothesis

a proposed explanation for a set of observations, and it leads to predictions that can be tested by performing experiments or making more observations

experiment

scientific test that is carried out in specific conditions

scientific theory

is broad in scope

• supported by a large and usually growing body of evidence

scientific inquiry

never proves the hypothesis true

• testing a hypothesis in various ways provides additional support and increases our confidence in our hypothesis

  • multiple rounds of hypothesis may lead to scientific consensus

scientific consensus

shared conclusion of many scientists that a particular hypothesis explains the known data and stands up to experiments

controlled experiments

in an experiment of a hypothesis, researchers often manipulate one component in a system and observe the effects of this change

independent variable

the factor that is changed

dependent variable

the measurement used to judge the outcome of the experiment

• variable depends on the manipulated variable

purpose of comparing an experimental group with a control group

the use of a control and experimental group can demonstrate the effect of a single variable

• ex. researchers found that mice models that didn’t match their habitat had higher prediction rates than camouflaged models

• hypotheses can be tested in humans with clinical trials, as well as retrospective or prospective observational studies

scientific thinking

hypotheses can be tested using observational data

observational data

scientists often use data from observations to form and test hypotheses

• to develop hypotheses about the evolutionary relationships among species, scientists use many kinds of evidence (observations of fossils and living organisms)

• scientists have increasingly used molecular evidence based on comparisons of DNA sequences to test hypotheses about evolutionary relationships

  • ex. red pandas

the scientific process

forming and testing hypotheses are at the core of science (collecting and interpreting data)

• process of science is repetitive, non-linear, and collaborative

  • exploration and discovery

    • observing, asking questions, reading literature

  • analysis and feedback from the scientific community

    • peer-reviewed publications, replication of findings, consensus building

  • societal benefits and outcomes

    • solving problems, developing new technologies

goal of science

to understand natural phenomena

goal of technology

to apply scientific knowledge for a scientific purpose

science and technology are interdependent

technology is used in scientific research and scientific discoveries lead to new technological advancements

• has a dramatic effect on society

  • discovery of DNA structure was due to x-ray crystal-logragraphy

  • climate change due to more and more people wielding technology (science can help slow it down)