Chapter 1: themes of biology Flashcards
Biology is…
the scientific study of life
An organism’s adaptations to its environment are the result of…
evolution
evolution is…
the process of change that has transformed life on earth
Life defies a…
simple one sentence definition
Life is recognized by…
what living things can do
Life is characterized by..
Order Evolutionary Adaptation Response to the environment Reproduction Growth and development Energy processing Regulation
Themes do what?
connect the concepts of biology
Theme 1
___ makes sense of everything we know about living organisms
Evolution
Organisms living on earth are…
modified descendants of common ancestors
Phylogenetic Tree of LIfe has 3 main branches…
Bacteria
Archaea
Eukaryota
Theme 2
New properties emerge at each level in the ___
biological hierarchy
Life can be studied at different levels from…
molecules to the entire living planet
broad levels of the biological hierarchy
the biosphere ecosystems communities populations organisms
specific levels of the biological hierarchy
organs and organ systems tissues cells organelles atoms & molecules
Theme 3
organisms ___ with their environments, exchanging matter and energy
interact
biotic
factoring in living organisms
abiotic
factoring in the nonliving
The dynamics of an ecosystem include two major processes…
Cycling of nutrients - in which materials acquired by plants eventually return to the soil
The flow of energy from sunlight to producers to consumers
The energy exchange between an organism and it’s environment often involves…
energy transformations
some energy is released to the surroundings as heat
energy flows through an ecosystem usually…
entering as light and exiting as heat
Theme 4
___ are correlated at all levels of biological organization
structure and function
example: flat leaves allow more surface area to absorb sunlight
Theme 5
___ are an organism’s basic units of structure and function
Cells
The cell is the lowest level of organization that can
perform all activities required for life
All cells are…
All cells use…
are enclosed by a membrane
use DNA as their genetic information
A eukaryotic cell has…
membrane enclosed organelles, the largest of which is usually the nuclues. other organelles are located in the cytoplasm.
(examples: plants, animals)
A prokaryotic cell is…
simpler and usually smaller, and does not contain a nucleus or other membrane enclosed organelles
(examples: bacteria)
Theme 6
The continuity of life is based on heritable information in the form of ___
DNA
DNA is…
(deoxyribonucleic acid) is the heritable material that directs cells activities
DNA is the substance of genes…
(units of inheritance that transmit info from parents to offspring)
Genes are organized onto…
chromosomes
DNA is found in…
mostly the nucleus (nuclear DNA) but a small amount is also found in the mitochondria (mitochondrial DNA)
An organism’s genome is…
it’s entire set of genetic instructions
DNA is transcribed into…
RNA then translated into a protein
Theme 7
___ regulate biological systems
feedback mechanisms
Enzymes do what…
catalyze or speed up chemical reactions in cells
many biological processes are…
self regulating through feedback mechanisms
negative feedback means…
that as more of an end product accumulates, the process that creates it slows and less of the product is produced
(example: body temperature regulation)
positive feedback means…
that as more of an end product accumulates, the process that creates it speeds up and more of the product is produced
(example: labor contractions)
The core theme
evolution accounts for the unity and diversity of life
Approximately how many species have been identified to date?
1.8 million species
the total estimate of species that actually exist range from?
10 to 100 million
Taxonomy is..
the branch of biology that names and classifies species into groups of increasing breadth
Taxonomy from broadest to narrowest…
Domain Kingdom Phylum Class Order Family Genus Species
The three domains of life
bacteria
> (prokaryotes)
archaea
Eukarya (eukaryotic organisms)
Eukarya includes three multicellular kingdoms….
and one unicellular…
Plantae
Fungi
Animalia
Protists (unicellular)
DNA is the…
universal genetic language common to all organisms
Unity in the diversity of life is…
evident in many features in cell structure
Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859
Darwin made two main points:
Species showed evidence of “descent with modification” from common ancestors Natural selection is the mechanism behind “descent with modification”
the environment “selects” for the
propagation of beneficial traits
Natural selection results in
the adaptation of organisms to their environment
There are two main types of scientific inquiry:
discovery science and hypothesis-based science
Discovery Science describes
natural structures and processes
This approach is based on observation and the analysis of data
Data are
recorded observations or items of information
Data fall into two categories
Quantitative, or recorded measurements, which are sometimes organized into tables and graphs
Qualitative, or descriptions rather than measurements
Observations can lead us to ask questions and propose hypothetical explanations called
hypotheses
A hypothesis is a
tentative answer to a well-framed question
A scientific hypothesis leads to predictions that can be tested by observation or experimentation
Deductive reasoning uses
general premises to make specific predictions
For example, if organisms are made of cells (premise 1), and humans are organisms (premise 2), then humans are composed of cells (deductive prediction)
A hypothesis must be
testable and falsifiable
Failure to falsify a hypothesis does
not prove that hypothesis
For example, you replace your flashlight bulb, and it now works; this supports the hypothesis that your bulb was burnt out, but does not prove it (perhaps the first bulb was inserted incorrectly)
In the context of science, a theory is:
Broader in scope than a hypothesis
can lead to new testable hypotheses
Supported by a large body of evidence in comparison to a hypothesis
The goal of science is to
understand natural phenomena
The goal of technology is to
apply scientific knowledge for some specific purpose