honors biology august 22, 2013 biology the study of life module 1
TRANSCRIPT
Honors Biology
August 22, 2013
Biology The Study of Life
Module 1
Class Challenge
Weekly Quizes
We are a 4-H Club !
Set up Experiments
Lab Book Set upTitle: Photosynthesis Experiment 1.APurpose:Supplies:Procedure:Hypothesis:Observations:Conclusion :
Dr Wile’s Introduction
What is Life??1. All life forms contain deoxyribonucleic
acid, which is called DNA
2. All life forms have a method by which they extract energy from the surroundings and convert it into energy that sustains them.
3. All life forms can sense changes in their surroundings and respond to those changes.
4. All life forms reproduce.
DNA
Provides the information necessary to take a bunch of lifeless chemicals and turn them into an ordered, living system.
In order to make life, we must take the chemicals that make it up and organize them in a way that will promote the other life functions mentioned in our list of criteria for life.
Criterions for Life
2. Extract and convert energy
3. Sense and respond to changes
4. Reproduction
The DNA is the set of instructions that takes the chemicals which made up life and arranges them in just the right way so as to produce a living system.
Energy Conversion and Life
Organisms need energy: The production and use of this energy is called metabolism.
Metabolism can be split into two categories:
1. Anabolism
2. Catabolism
Anabolism: The sum total of all processes in an organism which use energy and simple chemical building blocks to produce large chemicals and structures necessary for life.
Catabolism : The sum total of all processes in an organism which break down chemicals to produce energy and simple chemical building blocks.
Here’s an example
When you eat food, your body has to break it down into simple chemicals in order to use it. Once broken down, your body will burn those simple chemicals to produce energy or use them to make larger chemicals. This entire process of breaking the chemicals down and then burning them to produce energy is part of your body’s catabolism.
Now the process of making those complex chemicals from simple chemicals is part of your body’s anabolism.
One way to remember these two definitions is to notice that “catabolism” has the same prefix as “catastrophe” so they both involve things being broken down.
Energy that an Organism Gets
From its surroundings is important.
Where does it come from?
Ultimately all of the energy comes from the sun, which is the main energy
source for all living organisms on the planet.
Photosynthesis
Green plants as well as some other things that we will discuss later, take this light energy in and, by a process called photosynthesis, convert that energy into food for themselves.
If plants and other photosynthetic organisms absorb their energy from the sun, where do other life forms get their energy?
Well, that all depends…..
Some organisms eat plants. By eating plants, these organisms take in the energy that plants have stored up in their food reserves.
So indirectly they are absorbing energy from the sun. They are taking energy from plants in the form of food.
Organisms that eat only plants are called HERBIVORES
Herbivores
Animals that eat only plants
Figure 1.1 (page 4)
Carnivores
Organisms that eat only organisms other than plants.
Omnivores
Organisms that eat both plants and other organisms.
Producers, Consumers and Decomposers
Figure 1.2 (page 5)
Producers, Consumers and Decomposers
Producers are called Autotrophs. These are organisms that make their own food.
Consumers and decomposers are called Heterotrophs. These are organisms that depend on other organisms for their food.
Sensing and Responding to Change
The third criterion for life is that it senses and responds to changes in its surroundings.
It is must sense and have the ability to respond.
Living organisms are all equipped with some method of perceiving information about their surroundings.
Receptors- Special structures that allow living organisms to sense the conditions of their internal or external environment.
Examples of Receptors
Skin
All life forms Reproduce
Asexual Reproduction: Reproduction accomplished by a single organism. An organism can split themselves apart under the right circumstances. The two parts can then grow into wholly separate organisms.
Sexual Reproduction: Reproduction that requires two organisms. Organisms require a male and a female in order to reproduce.
All reproduction involves the concept of inheritance. Under normal circumstances, this is the process by which physical and biological characteristics are transmitted from the parent (or parents) to the offspring.
Asexual: identical copy of the parent
Sexual: is a mixture of each parent’s characteristics.
Mutations
In some instances, offspring can possess traits that are incredibly different from their parents. These incredibly different traits are the result of mutations. A Mutation is an abrupt and marked change in the DNA of an organism compared to that of its parent.
Scientific MethodFigure 1.3
Real science must conform to a system known as the scientific method.
This is the framework in which scientists can:
1. analyze situations,
2. explain certain phenomena, and
3. answer certain questions
This method starts with:
1. Observation. This allows the scientist to collect data. Once the data has been collected, the scientist forms a
2. Hypothesis. This is an educated guess that attempts to explain an observation or answer a question. Once he forms a hypothesis, the scientist then collects much more data in an effort to test the hypothesis. This data is often collected by performing experiments or making even more observations. If the data is found to be inconsistent with the hypothesis, the hypothesis might be discarded or modified a bit until it is consistent with all data that has been collected. If a large amount of data is collected and the hypothesis is consistent with all of the data then the hypothesis become a
3. Theory: it is a hypothesis that has been tested with a significant amount of data.
A Theory has been tested by a large amount of data, it is much more reliable than a hypothesis. As more and more data relevant to the theory are collected, the theory can be tested over and over again. If several generations of collected data are all consistent with the theory, it eventually attains the status of a scientific law.
Scientific Law
When a theory has been tested by and is consistent with generations of data.
Example: See page 10 of Dr. Semmelweis experiment of physicians’ handwashing.
Scientific laws are constantly being overthrown due to the fact that it is impossible to test them completely.
The Coelacanth Fish
Spontaneous Generation
The Hypothesis of Spontaneous Generation
That living organisms would just appear from matter if left in a particular manner.
Living Maggots on nonliving meat.
Eels have a similar smell and feel as the slimy ooze at the bottom of rivers.
Sweaty shirt placed in grain would produce mice.
What scientists did not understand was the world of microorganisms.
1670 Anton Van Leeuwenhoek fashioned his own microscope and used it to study water. He discovered the world of microorganisms.
Microorganisms are living creatures that are too small to see with the naked eye.
Through the years scientists experimented with various hypothesis to explain these microorganisms.
Did they spontaneously generate?
Louis Pasteur
In 1859, he finally demonstrated that even microorganisms cannot spontaneously generate.
Photosynthesis
Supplies: Clear glass containerA sprig of live fresh water aquarium plantA small sharp knifeAlcoholPaper towelA metal washerA sunny window or floodlampWater
Introduction:
In photosynthesis, plants can take energy from the light of the sun and use it to make food for themselves. One product of this process is oxygen gas. You will be able to observe this product being produces as a result of photosynthesis.
Procedure:
1. Wet the paper towel with alcohol and carefully wipe the blade of the knife. Make a fresh diagonal cut across the stem of the plant.
2. Thread the tip of the plant in the center of the washer and place it upside down into the glass and fill the glass with tap water until it is full. The stem should be under water.
3. Place the glass and plant in sunny window or under a lamp so that it is shining on the plant.
4. Wait 10 minutes and observe the stem of the plant where it has been cut.
5. Record what you observe.
Observations:
Conclusion:
Homework
Finish reading Module 1
Answer OYO questions 1.1- 1.5
Study Guide: Definitions a – u
Questions 2 – 9
Class Challenge:
Quiz: Know definitions and be able to explain The Scientific Method.