Download Keshara Senanayake Study Guide (BIO) Book notes (I suggest you

Keshara Senanayake
Study Guide (BIO)
Book notes (I suggest you look at the slides)
-Organisms: individual living things
-living things are characterized as
1) having complex organized structures that consist of organic carbon based molecules
2)they acquire materials/energy from their environment then convert it to different forms
3)actively maintain their complex structure and their internal environment, a process called homeostasis
4)they grow
5)respond to stimuli
6)reproduce themselves using DNA
7) have capacity to evolve (on the whole)
-life on earth is composed of a hierarchy of structures with each level based on the one below it (while
providing the foundation for the one above it)
-all life is built on a elements (unique matter).
-atom is smallest particle in an element that retains the properties of that element
-biosphere is the part of earth inhabited by living organisms; including living/nonliving components
-ecosystem: a community together with its nonliving surroundings
-community: 2 or more populations of different species living and interacting in the same area
-population: members of one species inhabiting the same area
-species: very similar, potentially interbreeding organisms
-organic molecules: carbon based
-the cell is the smallest unit of life
-All cells contain 1[ genes (units of heredity that provides the information needed to control the life of the
cell 2] organelles, miniature chemical factories that use the information in the genes and keep the cell alive
3] a plasma membrane, a thin sheet surrounding the cell that encloses the cytoplasm (the watery membrane)
that contains organelles and separates the cell from the outside world.
-in multicellular life forms, cells of similar type are combined into tissues which perform particular
function
-nervous tissue has neurons (individual nerve cells) that produce electric signals
-various tissues often combine to make up a structural unit called a organ
-several organs that perform a single function are called an organ system
-all the organ systems functioning cooperatively in a living things is the organisms
organisms need nutrients to survive. the sum of the total of all chemical reactions needed to sustain life is
called metabolism
-energy: ability to do work
-Plants to photosynthesis that turns energy from the sun and makes it into energy rich sugar
-fungi and animals must consume energy rich molecules from other organisms
-so technically energy from the sun goes to nearly all forms of life. Its eventually released again in the form
of heat
-Homeostasis: keeping the conditions in their body constant (such as body temperature)
-maintaining homeostasis is done in many ways: sweating during hot weather, metabolizing more food
during winter months
-growth involves the conversion of materials acquired from the environment into the specific molecules of
the organisms body
-organisms perceive and respond to stimuli in their environment
-continuity of life is when organisms reproduce giving rise to offspring of the same type
-DNA is deoxyribonucleic acid; has all the heredity information
-genes are segments of DNA
-an organisms DNA is its blueprint for its construction/operation
-when organisms reproduce it passes a copy to its offspring. 1 mistake in a billion
-occasional errors/accidents are called mutations. This is crucial so we aren't all the same. So we can
evolve.
-theory of evolution states that modern organisms descended with modifications from previous life forms
with adaptations
-natural selection: processes with organisms that have adaptations which can help them cope with their
environment better will survive and more successfully reproduce.
-organisms can be grouped into three major domains
1) bacteria: unicellular and prokaryotic
2) archaea: survive extreme conditions
3)eukarya
-bacteria and archaea and singe simple cells.
-members of the eurkarya have bodies composed or one or more highly complex cells and have 4
subdivided kingdoms
1) protista
2) fungi
3) plantae
4) animalia
- three important things used to characterize the domain and kingdoms are
1) cell type
2) the number of cells
3) mode of nutrition
- two basic different types of cells
1) prokaryotic
2) eukaryotic
-Karyotic refers to the nucleus of a cell
-eukaryotic cells posses a "true" membrane enclosed cell. They are much larger than prokaryotic
-prokaryotic do not have a nucleus, their genetic materials are in their cytoplasm
1) they are small
2) they membrane bound lack organelles
-prokaryotic evolved before eukaryotic
-bacteria and archea are prokaryotic cells
-the domains of bacteria/archea and the kingdom protista (from eukaryotic) are single celels.
-fingu/plantae/animalia are multicellular
-autotrophs "self-feeders" like plants, some bacteria and protists
-heterotrophs; organisms that can not photosynthesize meaning "other feeders". Like many archeans,
bacteria, protists, and all fungi/animals.
pgs 9 - 11
- All scientific inquiry including biology is based on small set of assumptions
>> Thoroughly tested, might be called "scientific principles"
>>>>> These are the principles of natural causality, uniformity in space and time, and common perception.
NATURAL CAUSILITY IS THE PRINCIPLE THAT CALL EVENTS CAN BE TRACED TO
NATURAL CAUSES
>>people look to religion
>>>science looks only to the principle of natural causality
A corollary to the principle of natural causality: the evidence we gather about the causes of natural events
has not been placed to fool us (people say fossils are placed on earth to test our faith)
THE NATURAL LAWS THAT GOVERN EVENTS APPLY EVERYWHERE AND FOR ALL TIME
>> ie, the laws of gravity, behavior of light, and interactions of atoms. They're the same as billions of years
ago, and even now. From NY to Moscow.
CREATIONISM is the belief that god created everything at a single time
>>scientist reject this because #yolo
SCIENTIFIC INQUIRY IS BASED ON THE ASSUMPTION THAT PEOPLE PERCIEVE NATURAL
EVENTS IN SIMILAR WAYS.
>>as a general rule all human beings perceive natural events in fundamentally the same way, and that these
perceptions provide us with reliable information about the natural world.
>>science cant solve moral issues, like the morality of abortion (its objection/opinionated)
THE SCIENTIFIC METHOD IS THE BASIS FOR SCIENTIFIC INQUIRY
SCIENTIFIC METHOD IS FOUR INTERRELATED OPERATIONS:
1) Observation 2) hypothesis 3) experiment 4) conclusion
Everything begins with observations of a SPECIFIC phenomenon. The observation lead to a question,
which after long thought becomes with a HYPOTHESIS. A hypothesis is a supposition based on previous
observations that is offered as an explanation for the observed phenomenon. We test the hypothesis to
check if it is valid, these EXPERIMENTS support or refute our hypothesis and we then make a conclusion.
- Simple experiments test a single factor (or variable)
- to become valid, the experiment has to rule out variety of other possible variables as the cause of
observation. They make CONTROLS in their experiment in which all variables remain constant. Control
then are compared with the experimental situation in which only the variable is being tested
Franceso Redi destroyed the theory on spontaneous generation of flys.
(makes everything above clear)
Observation --> flies swam around the meat left in the open; maggots appear on the meat
Hypothesis --> flies produce the maggots; keeping flies away from the meat will prevent the appearance of
maggots
Experiment --> Obtain two identical pieces of meat and two identical jars --> place meat in the jar
[open jar]
"control situation"
leave jar uncovered
gauze
[closed jar]
"experimental situation"
*experimental variable: guaze prevents entry of the flies*
leave exposed for several days
several days
*controlled variables: time, temperature, place*
flies swarm around and maggots appear
*Results*
cover jar with
leave covered for
flies kept from meat; no maggots appear
CONCLUSION:
spontaneous generation of maggots from meat does not occur; flies are probably the source of maggots
>> Remember good scientist is prepared to take advantage of chance events
>>Alexander Fleming --> found penicillin
DEPENDANT VARIABLE - measures effect of the independent variable
INDEPENDANT VARIABLE - is the only difference between the two groups
pg 267-269
-artificial selection: the breeding of domestic plants and animals to produce specific desirable features
>shows that natural selection is plausible
-canis lupus: wolf
-the variations of natural selection works are produced by chance mutations
-natural selection does not necessarily produce well adapted species
-evolution by natural selection selects for organisms that are best adapted to a particular environment
pg 277-278
-chance events that are likely to change the allele frequencies in a small population than in a large
population is called genetic drift
-genetic drift is an example of random genetic changes in small populations
-genetic drift reduces genetic variability within a small population
-genetic drift tends to increase genetic variability between populations
-Population bottleneck and found effect are two forms of genetic drift
1) population bottleneck: a population undergoes a drastic reduction in size as a result of natural
catastrophe or over hunting. Then only a few individuals are available to contribute to the future of the
population. This causes a change in allele frequency and reduction in genetic variability.
2) a special case of the population bottleneck, the founders effect is when an isolated colonies are founded
by small number of organisms.
pg 281-286
4 important points about evolution
- natural selection does not cause genetic changes in individuals (like cows eat a certain color flower, cows
merely favored the differential survival of one color)
- natural selection acts on individuals, but evolution occurs in populations.
-evolution is a change in the allele frequencies of a population owing to a differential reproduction among
organisms bearing different alleles.
-(the fitness of an organism is measured by its reproductive success)
- evolutionary changes are not "good" or "progressive" in any sense.
-natural selection is not the only evolutionary force. Mutations are provide a variability.
-natural selection is about survival and reproduction
-differential reproduction: individuals bearing certain alleles have more offspring (who inherit those alleles)
than do other individuals with different alleles
-natural selection act on phenotype (actual structure/behavior), which reflects the underlying genotype
--genotype (inside genes) reflects phenotype (outside)
-natural selection can influence populations in 3 major ways
1) directional selection: favors those who posses values for a trait at one end of the distribution range
(example, gets colder. Individuals with more fur survive)
2) stabilizing selection: favors those who posses average value of a triat against extreme sizes
(example: to big, spotted to easily by predator. to small, hard time defending territories. So average is
accepted)
3) disruptive selection: favors those with extreme values for a trait
(example: if environment favored the large/small but not the average)
-balanced polymorphism: in which two or more alleles of a gene are maintained in a population because
each is favored by a separate environmental force
-adaptations: are characteristics that help an individual survive and reproduce in an environment that
includes not only physical factors but also the other organisms with which the individual interacts
-non living: abiotic
(climate, availability of water, ect)
-living: biotic
(organisms to interact with)
-competition occurs with other members of the same species
-during predation, both predator and prey act as agents of selection
-constant mutual feedback between two species is called coevolution (predator-prey relationship)
-predation: when other animal consumes another
-symbosis: a relationship in which individuals of different species live in direct contact with one another for
prolonged periods of intimate interaction. Has different branches:
1) paratism: in which one species lives and feeds on a larger species
2) commensalism: in which one species benefits and the other remains unharmed
3) mutualism: in which both benefit
-sexual selection: helps organism mate
pg295-302
-species: a group of actually or potentially interbreeding natural populations which are reproductively
isolated from other groups
-speciation: the process in which new species form
-speciation depends on two factors
1) isolation of populations
2) genetic divergence
-allopatric speciation is in which two populations are geographically separated from each other
-sympatric speciation, which two populations share the same geographical area. Limited gene flow
-isolation from gene flow is key to both allopatric and sympatric speciation
-changes in chromosome number can cause immediate reproductive isolation of a population
-both natural selection and random events drive evolution
pg 351-264
-Systematists (the scientist who do the naming and classifying)
- systematic is the science of reconstructing phylogeny or evolutionary history
- 7 major categories (order from biggest to smallest) 1) kingdom 2) phylum (for animals; division for
plants) 3) class 4) order 5) family 6) genus 7) species
- the scientific name of an organism is formed from the two smallest taxonomic categories, the genus and
the species.
-the genus is a category that includes very closely related species that do not normally interbreed. The
species level includes very closely related species that do not normally interbreed. The species level
includes populations of organisms that can potentially interbreed.
-scientific names are always underlines, or italicized. The first letter of the genus name is always
capitalized, and the first letter of the species name is always lower-cased.
-Aristotle was among the first to attempt a logical standard of naming
- Swedish naturalist carl von Linne (Carolus Linnaeus) lead the ground work for modern naming
-the more categories two organisms share, the closer their evolutionary relationship
- the most important and useful of distinguishing characteristics has been anatomy. Taxonomist also use
skeletons and tooth structures
-phylum of vertebrates: chordata
-DNA (its genotype) its nucleotide sequence. Triggered revolution in studies of evolutionary relationships
- the relatedness around organisms can be evaluated by examining the structure of their chromosomes
- robert h whittaker in 1969 proposed the 5 kingdom classification scheme (kingdom monera -- single
celled prokaryotic. kingdom protista is single celled eukaryotic; remaining three in eukaryotic is: plantae
fungi and animalia)
-can be distinguished on how they gain nutrients. Members of platae photosynthesize, kingdom fungi
absorb, kingdom animalia ingest
-Bacteria and archea are classified as different due to a specific RNA difference found in the ribosome.
-two strands of dna can be separated by heating (the hyrogen bonding break and the two strands separate)
-amount of seperation can be measured by the absorption of UV light. Single DNA absorb more UV.
-the dna of two closely related species has more similar nucleotide sequences that does the DNA of
distantly related species. Also more heat is needed to break the hybrid double helix bond.
-fewer differences in nucleotide sequences indicate more closely related organisms
-bacteria (eubacteria) and archaea (archaebacteria) are different
- three main domains now
1) bacteria
2) archaea
3) eukarya
-a plant that produces seeds without fertilization: parthenogenetically
-the total range of species diversity is called biodiversity
-kingdom protista (for all 1 celled eukaryotic)
-brown / red multi cellular algae goes into the protists and green into plant kingdom
-microbes is found everywhere almost
-some of humanity's most deadly diseases stem from microbes
-viruses posses no membranes of their own, no ribosome on which to make proteins, no cytoplasm, and no
source of energy. They cannot move or grow, and they can reproduce only inside a host cell -- the cell a
viruses or other infectious agent infects.
-viruses consist of two major parts 1) a molecule of heredity material, either DNA or RNA, and 2) a coat of
protein surrounding the molecule
-each type of virus is specialized to attack a specific host cell
-even bacteria can fall victim to viral invaders; viruses that infect bacteria are called bacteriophages
-because viruses are intracellular infectious agents that require the cellular machinery of their host, their
illnesses they cause are difficult to treat.
-viral replication process follows this sequence
1) penetration: gets in; might be engulfed by host cell
2) replication: viral genetic material is copied many times
3) transcription: viral genetic information is used as a blueprint to make messenger RNA (mRNA)
4) protein synthesis: in host cytoplasm, viral mRNA is used to synthesize viral proteins
5) viral assembly: the viral genetic material and enzymes are surrounded by their protein coat
6) release: viruses emerge from the host cell by "budding" from the cell membrane or bursting from the cll
-viroids, particles that are short strands of RNS, lacking a protein coat. Viroids enter the nucleus of the
infected cell, where they direct the synthesis of new viroids.
-prions are protein only, and are infectious
-prions can be inherited as well as transmitted
--two of life's three domains consists entirely of prokaryotes, single celled microbes that lack organelles
such as the nucleus, chloroplast, and mitochondria.
-prokaryotes have been broken down to bacteria and archaea
-bacteria and archaea are similar under the microscope but they differ in structure and composition of their
cell walls and plasma membranes
-because their reproduction is usually asexual prokaryotic species cannot be defined on the basis of their
ability to interbreed
-they are classified by shape, pigments, sequence of DNA/RNA, ect
-a cell wall gives bacteria protection and their characteristic shapes.
-cell wall contains peptidoglycan
-gram-negative: include an additional out membrane resembling a plasma membrane in structure. Toxic
-more bacteria have "Capules" or slime layers" these help certain disease-causing bacteria escape detection
by their host anima's immune system
-to survive extreme conditions, bacteria form protective resting structures called endospores.
-pathogenic are disease producing bacteria
-under the domain archaea includes species such as methanogens (they convert CO2 to CH4). Halophiles
(survive in salt solutions), theoacidophiles (survive in hot/acidic conditions)
-many protists can reproduce asexually by mitotic cell division but also can sexually reproduce (called
conjugation)