biology notes chap 1

7/30/2019 Biology Notes Chap 1

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The study of biology

Definition

Biology - the scientific study of life or the organised study of life and living things their interaction

with one another and natural environment

Bio= Life Logos- Study

The importance of biology (Why)

General

- Better understanding about life- Appreciate the many diverse species and- How each species fits in the the dynamic patents of life on earth

Benefits of bio rsr

- Understand How the human function- Find cures for disease- Saving animal and plant extinction- Better management of problem related to environment-

Application knowledge and it principle development ofo biotecho genetic engineeringo food tech

- Development of application advance in medicine, agricultureo eg genetic engineering identify genes treatmentgene therapy

Different fields in biology - bio wide field of studydisciplines and branches

Living things

Zoology Animal

Botany plantsMicrobiologymicroorganisms

Taxonomy Classification of living and extinct organism

Living things and the environment

Ecologyrelationship between living organisms and their environment and how they

interact with both living and non living components in the environment

Biogeography - Geographical distribution of organism

Structures and fx of living organisms

Cytology struc and fx of cells

Anatomy Internal structure and organisation of living things

Bio-chemistry -Chemistry of living organismsMorphology - Forms & struc of organisms

Physiology Physical and biochemical fx & process of organisms

Change and development in living things over time

Genetic- Heredity and genetic variation

Paleontology the study of fossil

Applied Bio

Biotech - The application of biological process and living microorganisms in the industry

Medicine and veterinary Treatment and prevention of disease in both human and animals

Biomedicine- the application of biological and physiology principles to clinical practices


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Career related to biologywide rangecore for nursing, medicine, pharmacy, dentistry, veterinary

Biologists

Field work

Laboratory work

Health care

Agriculture and forestryMarine and freshwater

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Scientific investigation

Bio- sc study of life

Requires the use of sc. Skills -> 1) Sc process skills 2) Manipulative skills

Sc process skills - promote thinking in a critical, creative and analytical manner. Helps scientiets to

systematically find answers and explanation to phenomenon

Manipulative skills psychomotor skills required to carry out a successful scientific investigation

Steps involved in a scientific investigation

Identify a problem -> making hypothesis -> planning of investigation -> identifying and controlling

variables -> conducting experiment -> collecting data -> recording data -> analysing and interpreting

data -> making conclusion -> writing report

Steps involved in a scientific investigation

Identify a problem

- begin with observation of a specific phenomenon- based on observation- problem statement is made/formulated (How did it happen? Oh why

it is happening?)

- An inference which is logical conclusion or possible interpretation based on the observationmade. An inference is not necessarily a fact.

Making hypothesis

What is hypothesis ? A general statement about possible or a possible explanation for an

observation

Provide clear link between a manipulated variable and a responding variable

Hypotheses can be tested by conducting experiments.

Experiment => carried out=> Accepted or rejected and a conclusion is reached about its

validity.

Planning of investigations involves

- Gathering the relevant information abt or preparing the scientific background of anexperiment

- Determining the apparatus and material needed- Identifying the variables that influence the results of the experiments.- Determining the procedures- Determining observations to be made and measurements to be taken.


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- The correct and safe technique to be used when conducting an experiment needs to bedetermined.

Identifying and controlling variables

- Variables are factors or conditions which influence the outcome of an investigations- Normal- one variable of the experiment is tested each time. Determined before experimentcarried out.

- A manipulated variable V systematically changed to produce an observation. Independentvariable it is controlled at different values to test the validity of the hypothesis

- A responding variable -dependant variable (outcomes of an experiment). the resultsobtained due to the changes in the values in the value of Manipulated V. experiment. DATA

- Fixed or control V: are other possible factors which have significant effects on the outcomeof an experiment

- Fixed- constant throughout an experimentConducting Experiment

- The apparatus, materials, and speciments used must be handled correctly and safely.- All V must be determined and all observations must be made accurately and objectively.- The experiment design should include a control experiment for comparison- A control- similar in every aspect to the test experiment except that the manipulated

variable is keep constant.

- All apparatus after used, ,must be cleaned accordingly- correct procedure and technique,and returned to right places.

- All unwanted materials must discarded in a proper manner- A quantitative experiment is often repeated 3 times to obtain more precise and reliable

average or mean reading

Collecting data

- The result- data- Data obtained- mean of observation and measurement- The data gathered should be accurate and objective rather than subjective- Accuracy important in data collection

Recording data

- Data can be presented in the form of tables, graphs, charts or diagrams- Datatables

o Each column is labelled with the quantity and unitso The first row value-manipulated variables. Second- responding V or the dependant

variable (outcomes)

- Graphs- use to show relationship between variables- Manipulated- X- Responding- Y- Simple drawing is used to draw what is observed under microscope-labels various parts- give

each drawing a title.

Analysing and interpreting data

- Including tabulation and calculation of the results- Information of the data must be analysed, explained and interpreted in detail


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- The relationship between the manipulated variable and the responding variable must bestated clearly.

making conclusion

-rational conclusion accept/reject Hypothesis

writing report

communicated, writing based on findings

Objective state the aim of the experiment

Problem statement pose questions about the observations made

Hypothesis Formulate- a possible explanation or prediction based on observations.

Variables Identify and control the manipulated, responding and fixed variables.

Materials and apparatus List the materials and apparatus which will be used during the

experiment.

Technique State the technique involved in obtaining the results

Procedure - Write the instructions to carry out the experiments- The procedure should write in reported speech. For- Examine the slide under the microscope=> the slide is examined

under the microscope.

- Diagrams can be drawn to show the set-up of the experiment.They should be simple and two-dimensional. The apparatus

should be drawn with clear outline and labelled accordingly.

Results Present the results in the form of simple diagrams, charts, graphs or

tables. Include calculations where necessary

Discussion Discuss analyse and interpret the data obtained then determine the

relationship between the manipulated variable and the respondingvariable.


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Conclusion Draw a conclusion based on the hypothesis given earlier.

Example of experiments report

Problem statement

How is the fitness levels of students determined?

Variables (v)

Manipulated v: Subjects

Responding v: Time taken for pulse rate to return to normal

Fixed V: Controlled Type of exercise, gender, and age of subjects

Hypothesis

The students who is the fittest has the shortest recovery time Recovery time short- fits

Apparatus

A stool about 30 mins

A Stop watch

Technique

Count & record the pulse rate at one-min interval until its return to normal

Procedure

1. Pulse rates of the students in each group are measured before the test2. The pulse rates are measured by placing two fingers at the wrst. The number of beats over

15 seconds is counted and the multiplied by 4 to obtain the number of beats per mins.

Ensure all students are seated during the measurement taken.

3.

The subjects steps on to the stool with one foot and then second foot.4. This sequence s repeated for 3 mins at a constant rate about 30 steps per mins.5. Immediately after the test, the pulse rate of the subjects is measured at one-minutes

interval until its return to normal.

6. One of the subjects in each group will act as control.7. The results are recorded in Table 1.2 A. A graph of pulse rate (number of beats per minute)

against time for each subject is plotted (Figure 1.1)

Results

Discussion

- Figure- rate of heart beat /pulse reduce or decreases thereafter with time- Subject D has the highest pulse rate after the first step- During vigorous exercise, muscle requires o2 and glucose. Similar time CO2 is produced- Increase pulse-deliver o2 and glucose to muscle for cellular respiration and excrete CO2- Results all pulse rate decreases with time F constant (why) control- B shortest time- fittest student

Conclusion

B is the fittest student because he has the shortest recovery time. The hypothesis is

accepted.


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Experiment 1.2

Making bread using yeasts in the absence and present of sugar

Problem statement

How to does the absence and presence of sugar affect the time taken for a dough to double up size?

Variable

Manipulated: Absence/present of sugar

Responding: Time taken for the dough to double up in size

Fixed v: Amount of flour, yeast, and water used, temperature of water, and length of time to knead

the dough

Hypothesis

The dough take shorter time to double in size when sugar is present

Materials1.5 yeasts

5 g of glucose

100 ml of warm water

170 g of flour and a piece of cloth

Apparatuss

1000 ml beaker

250 ml conical flask

A mixing bowl

A stop watch

Technique

use A stop watch to measure and record the time taken for the dough to double up the size

Procedure

1. 5g of glucose is mixed with 100 ml of warm water in a conical flask2. 1.5 g of yeast is then dissolved in the sugar solution.3. The mixture is left aside for twenty minutes (proofing for yeast is active and fresh )4. Half of the flour is pour into a mixing bowl.5. A well is made in the centre of the flour and the frothy yeast mixture is poured into the well.6. The mixture is stirred well to make a soft dough.7. The remaining flour is gradually added until the dough becomes difficult to stir.8. At this point, the work surface is sprinkled with some flour. The dough is transferred onto

lightly floured surface.

9. The dough is kneaded for ten mins until it is smooth , elastic and no longer sticky.10.The dough is kneaded by turning, floding and pushing it down repeatedly with the heel of

the hand.

11.The kneaded dough is placed in a 1100 ml beacker and pressed down. Its initial volume isrecorded.

12.The beaker is covered with a clean cloth and placed in a warm spot.13.stopwatch Started, time for double up is recorded.14.Repeat steps 1-13 with similar ingredient for the dough except without sugar.


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Results

Dough Time taken for double up in size (minutes)

Dough with sugar 23

Dough without sugar 40

Discussion

1.The ingredient used as ingredient is flour, yeast and water

2. Proof yeast stage,

the amylase enzymes present in the moistened dough by

digesting the starch in the flour to produce maltose

Fermentation produce C02 Which cause dough to rise

Amylase

Starch -----

--Maltose + Sucrose + Co2 (Rises of the dough)3. sugar- speeds up fermentation process- faster in dough with sugar

4. warm water- temperature to enhance the action of amylase (enzyme in the yeast)

-if dough put in hot temperature. Oven. Yeast will be killed. No CO 2 so dough not rises. No

spongy and soft bread.

5. When carrying out the experiment, the height of the rises of yeast is measured and

recorded honestly and accurately.

6. If the experiment repeated with addition salt, the dough will not rise as the salt inhibits

the growth of the yeast and this prevent the dough from rising.

Conclusion

The dough takes a shorter time to double up in size if sugar is present. The hypothesis is

accepted.

biology notes chap 1

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