Exam 1 (intro to bio concepts) Flashcards
Some properties of living organisms
- A highly ordered structure (sunflower)
- regulation (organisms compensate for changes in internal and external environments- maintain homeostasis)
- Response to the environment(venus fly trap)
- Reproduction
- Growth and development
- Energy processing (butterfly obtains fuel from nectar and use energy in food to power self)
- Evolutionary adaptation (pygmy sea horse)
other definitions of what constitutes life
- living systems self-assemble against natures tendency toward disorder, or entropy
- life is a self-sustaining chemical system capable of Darwinian evolution
- Life is a network of feedback mechanisms
How does one begin to understand the functioning of complex biological systems?
- Biological “systems” range from cells to biosphere
- reductionism reduces complex systems to simpler components that are more manageable to study
- Systems biology studies how the components of complex systems interact and models these to understand how the system works
five unifying themes in biology (1)
new properties emerge at each level of biological organization
relationship between structure and function
structure reflects, determines function e.g. molecular structure of proteins determines function and flight/wing design in birds
relationship between structure and function (cells)
cellular function determines activities at all levels of biological organization e.g. movement of eyes caused by muscle and nerve cells
Life’s processes involve the expression and transmission of genetic information
DNA controls and directs development e.g. fertilized egg with DNA from both parents develops into an embryo with copies of inherited DNA. offspring has traits from both parents.
Information flow in DNA
- information is stored in DNA
- information is copied into RNA
- info in RNA guides production of proteins
Genomics
Genome- entire genetic material of an organism
Genomics-the study of whole sets of genes within, between species (facilitated by the ability to rapidly sequence genomes and analysis techniques)
proteomics-the study of gene products, proteins
theme 3 (life requires transfer and transformation of energy and matter)
-energy flow in plants (light, loss of heat, energy, other organisms)
Theme 4 (interactions)
Interactions (biological and physical) are important in biological systems at all levels – Molecular, biochemical – Cellular (t-cell killing cancer cell) – Symbiotic (wasps lay eggs on caterpillar) – Ecological (animals, sun, plants) - human also interact with environment and systems(climate change)
Feedback mechanisms
regulate biological systems
- negative feedback reduces initial stimulus(glucose level rises after meal which causes pancrease to secrete insulin. insulin causes body cells to take up glucose and liver cells to store it, thus decreasing lucose levels.
- positive feedback speeds up production (clotting of blood in response to injury)
Theme 5 (evolution)
– Accounts for the unity (shared ancestry)
and diversity of life
– Explains how organisms become adapted
to their environment
The diversity of life
Produced by an accumulation of adaptations
and genetic differences between
populations over long spans of time
• How many species have been described and
named?
– Estimates range from about 1.2 to 1.9 million
• What is earth’s total species diversity?
– Current range of estimates is from about 10
million to 100 million
• Thousands of new species named yearly
• Current species diversity represents less
than 1% of all species that have ever
hierarchy of classification
Domain kingdom phylum class order family genus species
three domains
• Bacteria—unicellular prokaryotes
• Archaea—unicellular prokaryotes
• Eukarya—unicellular and multicellular
eukaryotes
Kingdoms
plantae
fungi
animalia
protists
Underlying unity to life
- DNA, the molecule of inheritance
- Genetic code
- Metabolic pathways
- The amino acids used to build proteins
- Cells
Darwin
wrote orgins in 1859 Darwin explained three broad observations: 1. The unity of life 2. The diversity of life 3. How the close relationship between organisms and their environment comes about by natural selection
Darwin two main ideas
1. Descent with modification—present day species are descendants from different ancestral species—explained the unity and diversity of life 2. Natural selection—the proposed mechanism of descent with modification, adaptation
Darwin’s Observations of Species Populations
- Individuals in a population vary. Some of
this variation is heritable (i.e. traits are
passed on to offspring) - More offspring are produced than can
survive to reproduce - Species are adapted to their environment
Darwin’s Inferences Based on his Observations
- In a particular environment, some
individuals of a population possess traits
that give them a better chance of surviving
and reproducing than others - These individuals pass on their traits to
their offspring - This unequal survival and reproduction can
lead to the increase of favorable traits in
the population over generations - This natural selection can lead to
adaptation to the environment and new
species
Types of biological research (inquiry)
and data collection: Two different
approaches
1.Descriptive or discovery based science • Uses careful observation, analysis of data • This is frequently how research begins 2.Experimental or Hypothesis based science • Uses experimental data • Used to determine causes and explanations for observational data—answers why?
“The Scientific Method”
Is simply a critical process used to obtain
precise answers to questions
• It is not a “cookbook” formulation of steps
that must always occur in the same way and
in the same order
• A logical, flexible, creative process that is
analogous to everyday problem-solving
The Hypothesis
A potential answer to a scientific question
• A tentative explanation for some observed
phenomenon
• An educated guess
• Leads to predictions
• To qualify as a scientific hypothesis, it must
be testable and falsifiable (is it possible to
disprove?)
Hypotheses
If a tested hypothesis is supported by
experimental evidence science has “proven”
it to be true. Correct?
• Hypotheses are never “proven” from a
scientific perspective. Why?
• Generally not possible to test every variable,
set of variables or circumstances that might
influence some phenomenon
• Can only support, confirm, be consistent
with, etc.
Basic and Applied Research
• Basic research advances our knowledge of
living systems
• Applied research solves practical problems
Only if scientific methodology is properly
applied to answering a question can we
trust it as valid scientific information
Valid information we can trust is defined in
terms of how and why we know something,
not what we think we know
• Scientists view all new information with
skepticism and a highly critical perspective
• Thus, understanding the methodology of
science and the process of science is
important not only to scientists, but also the
public
• It allows us to judge whether information is
trustworthy
What are some qualities of science and
scientific information as opposed to
“nonscience?”
Based on what we can observe, directly or
indirectly, in the real world
• Uses critical methodology
• It is objective, non-biased
• Hypotheses are testable, falsifiable (What
evidence is needed to demonstrate it is
incorrect?)
• There are no absolute truths in science.
Conclusions are tentative and subject to
change, modification, and reinterpretation
What is not within the realm of Science?
-Not based on observations of the natural
world
• Explanations that are not testable, falsifiable
• Subjectivity, bias
• Beliefs based on faith, internal convictions,
moral values, or consensus
• Invoking some supernatural being or force to
explain some phenomenon
Scientific “theories”
• Theory is used very differently in science
compared to how we use it in everyday
conversation
• Not hypotheses, guesses, or speculations
• Explanations that scientists have great
confidence in
• Backed by a great deal of evidence,
supported by repeated tests under many
conditions
Example of a field experiment
• Observation: The coloration of deer mice (light vs. dark) blends in with the background of their habitat • Beach vs. inland populations 30 km apart • Main predators are visual • Question: Does camouflage affect predation rates on two populations of Peromyscus? • Hypothesis: Coloration of beach and inland mice provides camouflage that protects them from predation
