Download AP Bio Ch 1

Chapter 1
biology
Introduction: Evolution and the Foundation of Biology
- scientific study of life
- poses questions about living world
- seeks answers through scientific inquiry
evolution
- process of change that has transformed life from its beginnings to all species we have today
- fundamental principle of biology
5 unifying themes of biology:
New properties emerge at successive levels of biological organization.
Life’s processes involve the expression and transmission of genetic information.
Life requires the transfer and transformation of energy and matter.
Organizations interact with other organisms and the physical environment.
Evolution accounts for the unity and diversity of life. (It’s the core theme of biology.)
New properties emerge at successive levels of biological organization.
reductionism
- the approach of reducing complex systems to simpler components that are easier to study
Hierarchy of Biological Organization
biosphere
- consists of all life on Earth and all the places where life exists
ecosystem
- consists of all the living things in a particular area along with all the nonliving components
with which life interacts (soil, water, light, etc.)
community
- all of the organisms in a particular ecosystem (each type is called a species)
population
- all of the members of a particular species in a certain area
organism
- individual living thing
organ system - group of organs which performs a particular function(s)
organ
- arrangement of different tissues which performs a particular function
tissue
- group of similar cells that work together to perform a function
cell
- life’s fundamental unit of structure and function
- lowest structural level in which all of life’s properties can occur
organelle
- component of cells
molecule
- chemical structure consisting of 2 or more atoms
- arranged in organelles
atom
- chemical building block of all matter
emergent properties
- properties that result from interactions between components
- example: molecules have properties that their component atoms don’t have
- with each step upward in the hierarchy, new properties emerge that weren’t present
in the simpler levels
systems biology
- exploration of a biological system by analyzing interactions among its parts
Structure is related to function.
- analyzing biological structure gives clues about what it does and how it works
- knowing the function of something gives clues about its structure and organization
2 main forms of cells:
prokaryotic cells
eukaryotic cells -
- lack a nucleus and other membrane-bound organelles
- smaller than eukaryotic cells
- include bacteria and archaea
- contains membrane-bound organelles and nuclei
- make up plants, animals, fungi, and protists
Life’s processes involve the expression and transmission of genetic information.
chromosomes - structures within cells that contain genetic material in the form of DNA
genes
- units of inheritance
- stretches of DNA along a chromosome that codes for all the proteins made in a cell
- there are 100s to 1000s on each chromosome
DNA
- must first be replicated (copied) before a cell divides so each daughter cell can inherit a
complete set of chromosomes
- made up of 2 long strands arranged in a double helix
- each strand consists of an arrangement of 4 nucleotides (A, T, C, and G)
- the order of the nucleotides makes up the genetic code
RNA
- intermediary between the DNA and a protein
gene expression
- process by which the information in a gene directs the manufacture of a cell product
All forms of life use the same genetic code.
genome
- entire “library” of genetic instructions that an organism inherits
- typical human cell has 2 sets of chromosomes each with about 3 billion pairs of nucleotides
genomics
- the study of whole sets of genes on 1 or more species
- involves 3 research developments:
1- “high-throughput” technology (tools that can analyze biological materials very rapidly)
2- bioinformatics
- use of computers to store, organize, and analyze the huge volume of
data that results from high-throughput technology
3- interdisciplinary research teams (biologists, computer scientists, mathematicians,
engineers, chemists, physicists, etc.)
Life requires the transfer and transformation of energy and matter.
Cellular activities are work.
Work requires energy.
Input of energy comes mainly from the sun.
Transformation of energy from one form to another makes life possible.
Example:
chlorophyll in leaves of plants (producers) converts sun’s energy into chemical energy (sugar)
by photosynthesis
consumers eat plants and take in chemical energy and use it to perform work
some energy is converted to thermal energy and released to the surroundings as heat
Chemical elements (matter) are recycled in an ecosystem.
Example:
plant absorbs chemicals from air or soil and incorporate it into its body
chemicals are passed to an animal that eats the plant
chemicals are returned to environment by decomposers that break down wastes and bodies of
dead organisms
chemical can then be take up by plants again
Organizations interact with other organisms and the physical environment.
Organisms interact with all the biotic (living) and abiotic (nonliving) factors in their ecosystems.
Interactions between organisms not only affect the participants; they also affect how populations evolve over time.
Evolution accounts for the unity and diversity of life.
Evolution has produced a vast diversity of past and present organisms.
Many organisms share features.
Evolution explain the diversity (heritable changes over time) and the unity (descent from a common ancestor).
1.8 million species have been identified.
Scientists estimate there are 10 million to over 100 million living species today.
Classification of Life
3 domains:
Bacteria
Archaea
Eukarya
- diverse prokaryotes
- prokaryotes; many live in extreme environments
- contains 4 kingdoms: Animalia
- multicellular eukaryotes that ingest other organsisms
(ingestive heterotrophs)
Plantae
- multicellular eukaryotes that carry out photosynthesis
(autotrophs)
Fungi
- eukaryotes; most are multicellular; absorb nutrients
from outside their bodies (absorptive hererotrophs)
Protists
- eukaryotes; most are unicellular
On the Origin of Species by Means of Natural Selection - published by Charles Darwin in 1859
- 2 main points:
1. “descent with modification” - species have arisen from a succession of ancestors that differed from
them
- explained life’s diversity and unity
2. ”natural selection”
- the mechanism for descent with modification
Darwin’s 3 observations from nature:
1. individuals in a population vary in their traits which seem to be heritable (passed from parents to offspring)
2. a population can produce far more offspring than can survive (competition is inevitable)
3. species are generally adapted (suited) to their environments
Darwin suggested that individuals with heritable traits that are better suited to their environment are more likely
to survive and reproduce than are less well-suited individuals.
natural selection
- the “natural” environment “selects” for the propagation of certain traits
“Darwin’s finches”
- Darwin collected specimens of finches from the various Galápagos Islands in 1835
- believed to be descended from an ancestral species
- the finches diversified over time as they adapted to different food sources on the various
islands
tree diagrams - diagrams of evolutionary relationships
- extends back in time through ancestral species all the way back to prokaryotes
- similar species show a recent common ancestor
science - an approach to understanding the natural world
inquiry - a search for information and explanations of natural phenomena
scientific method
observation
data
- process of inquiry used by scientists
- includes:
making observations
forming logical hypotheses
testing hypotheses
- use of the senses to gather information directly or indirectly (with microscopes, etc.)
- recorded observations
quantitative data
- information expressed as numerical measurements
- often organized into tables and graphs
qualitative data
- information in the form of recorded descriptions
inductive reasoning
- generalizations are derived from many specific observations
- can lead to important conclusions (such as “All organisms are made of cells”)
hypothesis
- tentative answer to a well-framed question
- based on observations and guided by inductive reasoning
- leads to predictions that can be tested by experiments or further observations
- must be falsifiable
- becomes credible when it survives multiple attempts to falsify it (alternate hypotheses are
eliminated by testing)
deductive reasoning
- logic flows from the general to the specific (opposite of induction)
- predictions of results that will be found if a certain hypothesis is correct
- “if . . . then” logic
controlled experiment - one that is designed to compare and experimental group with a control group
- ideally both groups should differ only in the 1 factor the experiment is designed to test
scientific theory
- a theory is broader in scope than a hypothesis
hypothesis: If a mouse’s coat color matches its environment, it will be protected from predators.
theory:
Evolutionary adaptations arise by natural selection.
- a theory is general enough to spin off many, new, testable hypotheses
- a theory is generally supported by a much greater body of evidence
“Truth” is science is conditional (based on available evidence).
technology
- goal is to apply scientific knowledge for a specific purpose
- science and technology depend on each other (scientists use new technology in their research)