BIOLOGY 1M03 Study Guide - Gary Paul Nabhan, Conservation Biology, Insular Biogeography

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4 Feb 2013

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Ch 1 - Biology and the Tree of Life 12/10/2012 11:01:00 AM
Cell theory (all organisms are made of cells and that all cells come fro
preexisting cells) natural selection (species change through time b/c
individuals with certain heritable traits produce more offspring than others)
Phylogenetic tree - graphical representation of the evolutionary
relationships among species. Estimated by analyzing similarities and
differences in traits
Theory Is an explanation for a very general class of phenomena or
Cell theory and theory of evolution focus on what organisms are made of
and where they came from
Robert hooke used a crude microscope to examine the structure of a cork
from an oak tree - saw cells
Anton van Leeuwenhoek developed a much more powerful microscope and
was the fist to view single-celled animalcules in pond water. Also human
blood cells and sperm
A cell is defined as a highly organized compartment that is bounded by a
thin flexible structure called a plasma membrane and contains [ ] chemicals
in a aq solution
Where do cells come from? The first describes a pattern in the natural world
and the 2nd identifies a process that is responsible for creating that pattern
Spontaneous generation was a hypothesis
Biologists use a theory to refer to proposed explanations for broad patterns
in nature and hypothesis to refer to explanations for more tightly focused
Prediction is something that can be measured and that must be correct if
hypothesis is valid
*louis pasteur - refer to experiment in text (pg 3) or slides - proved that
cells arise only from preexisting cells and that the heat sterilization had not
altered the capacity to support growth
If all cells come from preexisting cells, it follows that all individuals in a pop
of single celled organisms are related by common ancestry
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Darwin and Wallace claimed that species are related by common ancestry
and that the characteristics of species can be modified from generation to
generation “descent with modification”
Evolution - species are not independent and are related to one another
Natural selection occurs whenever 2 conditions are met: individuals within
a population vary in characteristics that are heritable and certain heritable
traits help individuals survive better or reproduce more than do other
Population is defined as a group of individuals of the same species living is
the same area at the same time
**natural selection acts on individuals but evolutionary change affects only
**evolution occurs when heritable variation leads to differential success in
Fitness - the ability of an individual to produce offspring. Higher fitness =
more offspring
Adaptation - a trait that increases the fitness of an individual in a particular
Ex/ to create broccoli, horticulturists selected mustard species that were
large and compact flowering stalks - over generations made broccoli
Speciation - where natural selection caused populations of one species to
diverge and form a new species
Speciation supports a clam that Darwin and Wallace made - that NS can lead
to change b/w species as well as within
Tree of life - a family tree of organisms
Taxonomy - effort to name and classify organisms
Carolus Linnaeus’s system: first part indicted the organism’s genus (closely
related group of species) and the second identifies the organism’s species
(made up of individuals that regularly breed together or have characteristics
that are distinct from those of other species
An organism’s genus and species designation is called its scientific name
(always italicized). Genus names are capitalized
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Linnaeus said that diff types of organisms shouldnt be given the same genus
and species names. Naming system is called binomial nomenclature
Taxonomic levels: species, genus, family, order, class, phylum and
For humans: homo sapiens, homo, hominidae, primates, mammalia,
chordata, animalia
Linnaeus proposed that species could be organized into 2 kingdoms - plants
and animals. Organisms that do not move and produce their own food are
plants XX
Eukaryotes with a nucleus and prokaryotes are unicellular and w/o
Now we have 5 kingdoms: monera (prokaryotes), protista (unicellular
eurkaryotes), plantae, fungi, and animalia
Carl Woese and colleagues’ goal was to understand phylogeny of all
organisms - their actual genealogical relationships. They needed to study
Woese: if the theory of evolution is correct then rRNA sequences should be
very similar in closely related organisms but less similar in organisms that
are less closely related
Phylogenetic tree - a diagram that depicts evolutionary history. Branches
are close to one another are closely related
Fundamental divisions in organism: the bacteria, Archaea and eukaryotes
Woese created a new taxonomic level called domain.
Some of the kingdoms that had been defined earlier do not reflect how
evolution actually occurred
Bacteria and archaea are much more diverse than anyone imagined
Why do giraffes have long necks?
FOOD COMPETITION: giraffes compete for food with other species of
mammals. Giraffes with longer necks can reach food that is unavailable to
other species. As a result, giraffes with longer necks survived overtime.
However proved to be wrong because giraffes usually bend their necks to
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