Download T-1 Chapter One: Biology- Study of Life

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Chapter One:
Biology- Study of Life
 All living things and all places they are found on Earth make up the Biosphere. The Biosphere
includes land environments, such as deserts, grasslands, and different types of forests. It also
includes freshwater and saltwater, as well as portions of the atmosphere. Even the inside of
your nose, which houses bacteria and fungi, is part of the biosphere.
 Across the biosphere, the variety of life is called Biodiversity. Biodiversity increases as you
get closer to the equator. WHY?
 Within the living world, living things are grouped into species. Species are defined by living
things that can reproduce by interbreeding. Approximately 2 million different living species
have been discovered, but most scientists believe there are 10’s of millions more.
 When you study biology, you are studying living organisms. An Organism is any individual
living thing.
 If you study living things, you are studying organisms that share a common set of
characteristics. They are:
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 Characteristics of Living Things:
a) All organisms are made up of one or more cells.
- A cell is the basic unit of life. Single-celled organisms are the most common organisms on
Earth, while multi-cellular organisms are the other type. Cells in multi-cellular organisms
specialize to perform specific functions within the organism (ie: muscle cells, skin cells,
brain cells, etc…)
b) All organisms must obtain energy.
- In order for living organisms to work, they must acquire energy. The form of energy living
organisms’ use is Chemical Energy. Some organisms make their own food, like plants, and
some organisms ingest their food, like animals.
- Energy is needed to keep your Metabolism functioning. Your metabolism is all the reactions
that happen in your body.
c) All organisms respond to their environment.
- To survive, organisms must react to environmental changes. Changes in light, temperature
and other climate changes make it hard for an organism to survive unless they change their
behavior. Fear is a response to being in danger.
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 Characteristics of Living Things (continued):
d) Living things reproduce and develop.
- Members of a species must have the ability to reproduce. In reproduction an
organism passes on its genetic material (DNA) to its offspring. Reproduction can be
done with one parent (asexually) or two parents (sexually).
Section 1.2: Themes of Biology
 The world is organized as a bunch of systems. A system is an organized group of related parts that
interact to form a whole. (ie: parts of a car)
 Systems are big and small. Molecules and cells working together is a system. Also, when two organisms
interact that can also form a system. We are all part of what is called an Ecosystem. An ecosystem is all
living and non-living things interacting with each other.
 An ecosystem can be as big as a forest or as small as an individual bush. Ecosystems are the physical
environment and the organisms that interact within the environment.
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 Structure and Function:
o Structure and function are related to living things. Generally speaking,
the shape of something in living things tells us what it’s function is (ie:
front teeth vs. back teeth……front teeth bite and tear, while back teeth
grind).
o Cells have different functions that depend on their specialized
structures.
 For example: Brain cells function to receive and give information.
They are built with extensions off of the cells to receive information.
 Blood cells carry oxygen and must fit through very small vessels.
 Plant cells must be rigid and tough to hold a plant upright
o Cells are the basic unit of structure and function. This means it is the
smallest part of living organisms that does carry on all of life’s function.
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-Organisms must maintain a constant environment within themselves. Outside temperatures and
conditions are always changing; however, the conditions inside an organism must stay the same.
o How does a human live outside when it’s freezing?
o How does a polar bear live in the Arctic?
 Homeostasis is the maintenance of constant internal conditions in an organism. Homeostasis
is important because cells function best within a limited range of conditions. Things like
temperature, blood sugar, acidity, and other conditions must be controlled. If homeostasis is
not maintained, problems arise.
 How does your body know when homeostasis is out of whack?
o Your body starts a process called Negative feedback. In negative feedback, your body
reacts to a change in a system. For example, if you have a fever, your body starts to
sweat in order to cool down. Or, if you’re cold, your muscles start to shake. It is called a
“shiver” and pumps blood to warm you up.
o Behavior also regulates your body.
 For example: if you are cold, you put on a coat or a snake will sit on a warm rock to
warm up.
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 How do things become different from one time to another? What explains how things are
constantly changing?
o Evolution is the change in living things over time. This change comes about because
species genetic makeup changes do to an ever changing environment. (ie: giraffe’s and
their necks)
 One way things change over time is through adaptations. An adaptation is an inherited trait
that gives that organism an advantage in survival.
 No two organisms have the same adaptations. What works for one species may not work for
another.
 Evolution is unique because it not only explains the diversity in life, but also the similarities
of life.
o ie: you may think bacteria and humans are totally unalike, but they actually share many
of the same genes!
 Evolution picks for the strongest traits. Any trait that is helpful for the survival of the species
usually gets selected and passes on. That means if a certain gene is helpful to make a certain
protein, both bacteria and humans may have it.
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Section 1.3:
 Scientific thinking and processes:
o All scientific inquiry begins with careful and systematic observations. Observations
include using all of one’s senses to study the world.
o Scientists are constantly trying to understand the world around us. All findings must be
supported by evidence. All findings must also be repeatable.
o Once observations are made, Data is collected. When scientist collect data they usually
put it into 2 categories:
1) Quantitative- this is data that can be measured (things like mass, volume and
temperature).
2) Qualitative- this is data that are descriptions of sights, smells or sounds (nonmeasurable).
 Once data is observed, a Hypothesis is made. A Hypothesis is a proposed answer to a
scientific question. A hypothesis must be testable.
 Most all hypotheses are tested using controlled experiments. However, you can
also test a hypothesis by simple observation (ie: speeding down a street).
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Section 1.3:
 Most all hypotheses are tested throughout experimentation. Experiments have a couple of very
important parts:
1) Independent Variable- this is the condition that is being manipulated or changed. This is
what is added to the Experimental Group and not added to the Control Group.
2) Dependent Variable- this is an outcome….. the dependent variable is what happens
because of the independent variable.
3) Constants- conditions in an experiment that do not change.
 In an experiment the Control Group is what contains the constants and the Experimental Group
contains the variables.
 Once an experiment is concluded, conclusions must be made. If the experiment came out negative,
the hypothesis was proven false. If the hypothesis is proven correct, a theory is formed. A Theory is
a proposed explanation for events that have occurred.
 A Scientific Law is different than a theory, because a law is accepted as fact everywhere.
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Section 1.4:
 Biologists Tools:
o Until the late 1600’s, no one knew what a single-celled organism was. However, with the invention of the
microscope, things could be seen like never before.
o A microscope provides an enlarged image of an object. The first microscopes were blurry, but by the
1800’s clear microscopes were produced. Today, there are different types of microscopes:
 Light Microscope- these are like the ones we use. They shoot light at the specimen and magnify it.
 Scanning Electron Microscope- shoots electrons at the surface of the specimen and scans it.
 Transmission Electron Microscope- shoots electrons through a thin slice of specimen.
 Other advanced computers, MRI’s and genetic testing systems have become more advanced as well. The tools
scientist use are every growing, but the best tool is still the Scientific Method.
1. State the problem
2. Form a Hypothesis
3. Test the Hypothesis
4. Record and Analyze the Data
5. Reach Conclusions
6. Retest!