Chapter 1 - The Science of Biology Flashcards
Properties of Life - Living organisms:
- are composed of cells
- are complex and ordered
- respond to their environment
- can grow and reproduce
- obtain and use energy
- maintain internal balance
- allow for evolutionary adaptation
Basic unit of life is the
cell
Levels of Organization - Cellular Organization
atoms - molecules - organelles - cells
Levels of Organization - Organismal Level
tissues - organs - organ systems - organism
Levels of Organization - Population Level
population - species - community - ecosystem
Emergent properties
new properties present at one level that are not seen in the previous level
(Each level of organization builds on the level below it but often demonstrates new features.)
Science aims to understand the natural world through
observation and reasoning
Much of science is purely descriptive.
Deductive reasoning
uses general principles to make specific predictions
Inductive reasoning
uses specific observations to develop general conclusions
Scientific method (systematic approach to gain understanding of the natural world)
- Observation
- Hypothesis formation
- Prediction
- Experimentation
- Conclusion
hypothesis
a possible explanation for an observation
(-must be tested to determine its validity
-is often tested in many different ways
-allows for predictions to be made)
experiment
- tests the hypothesis
- must be carefully designed to test only one variable at a time
- consists of a test experiment and a control experiment
reductionism
break a complex process down to its simpler parts
models
to simulate phenomena that are difficult to study directly (have limitations and are only as good as their data)
Germ Hypothesis (related to nutrient broth experiment)
preexisting microorganisms present in the air can contaminate the nutrient broth
Spontaneous Generation Hypothesis
Living organisms can be generated spontaneously from nonliving organic molecules in broth
scientific theory
- is a body of interconnected concepts
- is supported by much experimental evidence and scientific reasoning
- expresses ideas of which we are most certain
Proposed that evolution occurs by natural selection
Charles Darwin
evolution
modification of a species over generations
(“descent with modification”
proposed by Darwin)
natural selection
individuals with superior physical or behavioral characteristics are more likely to survive and reproduce than those without such characteristics
(proposed by Darwin)
Darwin’s evidence - Similarity of related species
Darwin noticed variations in related species living in different locations. (specifically finches from the Galapagos Islands)
Darwin’s evidence - Population growth vs. availability of resources
- population growth is geometric
- increase in food supply is arithmetic
- Darwin realized that not all members of a population survive and reproduce.
- Darwin based these ideas on the writings of Thomas Malthus.
Post-Darwin evolution evidence - Fossil record
- New fossils are found all the time
- Earth is older than previously believed
Post-Darwin evolution evidence - Mechanisms of heredity
Early criticism of Darwin’s ideas were resolved by Mendel’s theories for genetic inheritance.
Post-Darwin evolution evidence - Comparative anatomy
Homologous and analogous structures
Homologous structures
have same evolutionary origin, but different structure and function
(such as human arm w/ hand, cat leg w/ claw, bat wing, porpoise paddle, horse leg w/ hoof)
Analogous structures
have similar structure and function, but different evolutionary origin
(such as wings of birds, moths, butterflies, bats, pterodactyls, etc.)
Post-Darwin evolution evidence - Molecular evidence
Our increased understanding of DNA and protein structures has led to the development of more accurate phylogenetic trees.
Phylogenetic trees
A pattern of descent generated by analysis of similarities and differences among organisms. Modern gene-sequencing techniques have produced phylogenetic trees showing the evolutionary history of individual genes.
Unifying Themes in Biology - Cell theory
All living organisms are made of cells, and all living cells come from preexisting cells.
Unifying Themes in Biology - Molecular basis of inheritance
DNA encodes genes which control living organisms and are passed from one generation to the next.
Unifying Themes in Biology - Structure and Function
- The proper function of a molecule is dependent on its structure.
- The structure of a molecule can often tell us about its function.
Unifying Themes in Biology - Evolutionary Change
Living organisms have evolved from the same origin event. The diversity of life is the result of evolutionary change.
Unifying Themes in Biology - Evolutionary Conservation
Critical characteristics of early organisms are preserved and passed on to future generations.
3 Domains
Bacteria, Archaea, and Eukarya
Prokaryotes
- Single-celled organisms (no nucleus) with little internal structure
- Bacteria and Archaea
Eukaryotes
Organisms with complex, organized cell or multiple complex cells (cells have a nucleus)
4 Kingdoms of Eukarya
Plantae, Fungi, Animalia, Protista
Characters of Kingdom Plantae
Organisms with cell walls of cellulose and obtain energy by photosynthesis
Characters of Kingdom Fungi
Organisms with cell walls of chitin and obtain energy by secreting digestive enzymes and then absorbing the products they release from the external environment.
Characters of Kingdom Animalia
Organisms that lack cell walls and obtain energy by first ingesting other organisms and then digesting them internally.
Characters of Kingdom Protista
All the unicellular eukaryotes except yeasts (which are fungi) and multicellular algae.
Unifying Themes in Biology - Cells - information processing systems
Cells process information stored in DNA as well as information received from the environment.
Unifying Themes in Biology - Emergent properties
New properties are present at one level of organization that are not seen in the previous level.
biology
The study of living things; the science of life.
Darwin
- Charles Darwin - naturalist
- Sailed on the HMS Beagle about 180 years ago as ship’s naturalist.
- 5-year journey that led to development of the theory of evolution by natural selection (core of the science of biology).
- Wrote “On the Origin of Species”
Wallace
- Alfred Russel Wallace
* Independently developed theory of natural selection, 16 years after Darwin.
Malthus
- Thomas Malthus
- Wrote “An Essay on the Principle of Population” (1798)
- Stated that populations of plants and animals tend to increase geometrically, while humans can only increase their food supply arithmetically.
- Influenced Darwin’s development of theory of natural selection - those surviving individuals with physical or behavioral advantages tended to pass those traits along to their offspring.
Galapagos Islands
Group of islands 960 km (600 miles) off coast of Ecuador. Darwin discovered 14 species of finches which provided evidence for evolution by natural selection.
Darwin’s finches
14 species discovered on the Galapagos Islands which were related but differed slightly in appearance, specifically their beaks. Beaks were modified to adapt to the particular food sources available to each species. Resembled species from South America.
experimental variable
The one variable that changes between the control and test group.
(independent variable)
experimental control
?? (the control group in an experiment?)
HMS Beagle
Ship that Darwin spent 5 years on
vestigial
A morphological feature that has no apparent current function and is thought to be an evolutionary relic (sch as hip bones of a boa constrictor)
