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B
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O
L
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G
Y

SUMMARY
INTRODUCTION - BIOLOGY
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11

CHARACTERISTICS
OF LIVING BEINGS

Chemical Composition of Living Matter
Everything that exists in nature, including living beings, is compounded
by atoms
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Phosphorus (P) and Sulphur (S) - in a smaller amount
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Inorganic Compounds/Substances - water and mineral salts
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In other words, a cell is a
unit of life
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Examples: bacteria, protozoa, and unicellular algae
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Examples: animals and plants
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There are two metabolic pathways:

Anabolism: a chemical reaction that produces
atoms, and molecules
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Cells are constantly replacing their components: breaking the old
molecules via catabolism and building new ones via anabolism
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Trivia: While we are asleep anabolism and catabolism are balanced
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In other words, self-sufficient
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Examples: plants, algae, and specific bacteria
Heterotroph: an organism that isn't able to produce its food
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Examples: animals, protozoa, fungi, and the majority of bacteria
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Single-celled organisms grow by their cell
getting bigger, while multicellular grow due to the increase of the total
number of cells in their body
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Reproduction can
generate:

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Biodiversity
acquired
by
sexual
reproduction, which
is
a
fusion
of
gametes from two different beings, and the
born
individuals
are similar to their
progenitors
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Or when a
multicellular creature multiplies its cells,
doubles its size, and also divides in two
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Genetic Variability, Mutation, and Natural Selection
The fusion of two gametes leads to genetic recombination and,
consequently, an individual variation, as seen in a previous topic
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Sometimes,

perpetuate

with

the

variations
duplication

suffer
of

mutations

genetic

material

that
for

reproductive means
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The mutated portion of the species, associated with the
environment that from time to time changes, can prevail when
their non-mutant similars die due to this alteration, and thanks
to this particular mutation, the population is left alive and
capable of developing new characteristics that will help them
again in case of a new environment modification
...
It can interact
with the environment, so its absence or
abundance can be decisive to the perpetuation
of its counterpart
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LEVELS OF
ECOLOGICAL
ORGANIZATION

Inside an Organism
Nature follows a hierarchy, so in order to comprehend biology, we study
organizational levels, where one element constitutes the next one, being
fundamental to their existence
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When bonded
with other atoms form molecules
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At the moment that they get
complex enough , they are combined to make organelles
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Cell: studied by biologists, the basic unit of life reunites with
others that execute the same role as them constituting a tissue
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Several tissues collectively work in an
organ, even if they fulfil distinct tasks, their purpose is the same ensure the functioning of the organism
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System: organs integrated, developed to effectuate corporal
functions and provide everything a living being may need to work
properly
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Observations:
- viruses are acellular, meaning they are only compounded by atoms and
molecules
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- with those pieces of information, it is a fact that a few organisms don't have all
levels of biological organization
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Community: also referred to as Biocenosis
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The biotic elements of an
environment
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A place with singular
characteristics, like the climate, where a particular form of life or
many species are enabled to develop
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The environment's
biotic and abiotic components interact, modifying each other's
chemical composition
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Biosphere: the highest position in the hierarchy, a reunion of all
ecosystems on Earth, along with the hydrosphere (the sum of
Earth's water), the atmosphere (gases surrounding the planet),
and the lithosphere (crust and solid outermost layer of Earth's
upper mantle)
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?

Elaborate Questions: contemplate why a
certain event happens, investigate the
link between the facts of this problem to
find more topics, and formulate even
more questions
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Observations:
- a hypothesis can only be validated if it's testable through experiments or by
imagining a new situation where specific facts and consequences will happen just
if the hypothesis is true
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- the term theory isn't an equivalent word to hypothesis, it's a compilation of
knowledge that offers a more complex explanation and interpretation of facts
that have been verified right by the approval of multiple hypotheses
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Analyze Results: evaluation of the
data gathered in the experiments
to reach a conclusion, more
precisely, confirm or refute the
hypothesis
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If
it's proven correct it's certified, and it
might be taken as evidence to help clarify
another hypothesis
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BIOGENESIS
VERSUS

ABIOGENESIS

Abiogenesis
Abiogenesis:

A = Not

+

Bio = Life

+

Genesis = Origin

Aristotle (384 - 322 a
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)
Was one of the defenders of the spontaneous generation theory, which
presumed that life arose from non-living matter because it contained a
"vital force"
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Since the spread of his thinking in the occidental culture occurred due
to his significant influence, the abiogenesis theory achieved popularity
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- He heated the broth as a manner of sterilizing it, that is, exterminating
the microorganisms (living matter), and closed the jar
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=

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Biogenesis
Biogenesis:

Bio = Life

+ Genesis = Origin

Francesco Redi (1626 - 1697)
Before Needham attempted to confirm the spontaneous generation, a
physician, Redi, demonstrated that organic matter didn't create a living
being through an experimental group and a control group
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Control group: flask covered with meat inside, flies couldn't land on larvae didn't appear
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Open container - with meat inside, insects could land on - grub
appeared
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Jar covered with gauze - (an air-only passage, to not prevent airflow
inside the flask) flies were attracted by the smell but couldn't land on
the meat inside the container, so laid eggs on the gauze, maggots
didn't survive without nutrition
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The passage
should be hermetically sealed, with no passage for air, seeing that
microorganisms enter the container carried by air and contaminate the
broth - only proved later by Pasteur
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Needham opposed saying that this way, the process killed the
active principle
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His experiment consisted of: filling with broth two types of flasks - one
with a straight neck and the other one with a curved-swan neck
resemblance, melted and molded by himself
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While the steam got out of the swan neck flask by its extremities, the
deposition of particles of water happened, similar to a filter, and so did
the air that was inside
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Except that only occurred with the straight-neck flask
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Despite being in direct contact with air, it retained the microorganisms
in the curves of the swan neck flask, it's just like a filter remember?
This way, the air that touched the broth didn't have bacteria present
in it
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Fun Fact: Redi took the idea that meat in decomposition has an
important role in the life cycle of flies from the Iliad, with the
authorship attributed to Homer
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Creationism or Special Creation
Based on Biblical literalism, specifically in Genesis book, this theory
considers the religious aspect where a supernatural Creator is responsible
for all forms of life and where it manifests
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The creatures stay the same
way as they have ever been
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Panspermia
Having the knowledge that non-living matter can't create life, scientists
began to theorize that it might have come from extraterrestrial life
precursor substances or living beings that arrived from other parts of the
Universe in meteors, that crashed on Earth billions of years ago and
colonized our planet
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Confirm the successive process of
modifications of species over time by the evidence of past - fossils
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Oparin - Haldane Hypothesis - Coacervate Theory
Covers the chemical evolution theory, suggesting the evolution of
chemical elements - bonded atoms that turned into molecules
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After the Earth's surface cooled down it formed its crust, the
water vapor got condensated in the highest levels of the atmosphere;

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When condensation happens the water blends with other substances
that are also in their gas state, but the chemical elements could only
bond in a more complex form at the time water didn't instantly
evaporate while touching the surface, in its liquid state
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Miller - Urey Experiment
A chemistry experiment system made in order to simulate the conditions
of the early Earth proposed by Oparin and Haldane to test the hypothesis
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COMPARISON TABLE
Oparin - Haldane + Miller - Urey

H2 = Hydrogen
NH3 = Ammonia
CH4 = Methane
H2O = Water (vapor)

Real Atmospheric Composition had:

N2 = Nitrogen
CH 4 = Methane
CO2 = Carbon Dioxide
CO = Carbon Monoxide

Miller - Urey Experiment resulted in simple organic compounds like amino
acids

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