Biology Lecture Notes

General Education Course: Biology

Introduction

  • The lecture covers a broad range of topics in biology, starting from the origin of life to various scopes and applications of biology.

Initial Observations

  • There are more bacteria on the skin of one person than the number of people ever.
  • Listing of biological kingdoms: Monera, Protista, Fungi, Plantae, Animalia
  • Mention of various biological terms: Cell, Mitosis, Genetics, Binary fission, Amoeba, Amylase, Synapses, Ribonucleic acid (RNA), Osmosis.
  • Discussion of environmental issues: Pollution is any harmful addition to the environment; Eutrophication leads to dead fish.
  • Listing of viruses: Meningitis, H1N1 Influenza, Myxomatosis, HIV, Polio.
  • Question about identical twins: Why are identical twins not identical even though they have identical genes?
  • Basic genetics: Male (XY), Female (XX) chromosomes.

Lecture 1: Origin of Life and Scopes of Biology

  • Topics covered: Origin of Life, Biology Scopes, Big Bang Theory, Origin of Earth, Earth without life, Evolution of life.
  • Big Bang Theory: The universe originated from an explosion from a pin-sized point to a huge universe.
  • Earth is unique: Among all planets, only Earth contains life.
  • Early Earth conditions: High temperature, poisonous gases, no free oxygen/water.
  • Evolution of life: Life evolved from chemical reactions and gradual changes.
  • Cellular beginnings: Life begins when the cell forms, progressing from single to multi-cellular organisms.
  • Survival of the fittest is a key concept.

What is Biology?

  • Etymology: Biology = Bio (life) + logy (study of).
  • Definition: The science of life and living organisms.
Organisms
  • Living entity consisting of:
    • Single cell: e.g., bacteria.
    • Several cells: e.g., animals, plants, & fungi.

Cell Structure

  • Animal Cell:
    • Key components: Lysosome, cytoplasm, microtubules, smooth endoplasmic reticulum, free ribosome, ribosome, mitochondrion, rough endoplasmic reticulum, plasma membrane, microvillus, microfilament, centriole, nucleus, nucleolus, chromatin, nuclear pore, Golgi complex, nuclear envelope.
  • Plant Cell:
    • Key components: Cell wall, rough endoplasmic reticulum, nucleus, microbody, vacuole, mitochondrion, ribosomes, plasma membrane, central vacuole, Golgi body, smooth endoplasmic reticulum, chloroplasts, plasmodesmata, lysosome, nuclear envelope, cytoplasm.

The Scientific Method

Step 1: Make Observations
  • Claim: Many people have claimed that consuming extracts of the herb echinacea can reduce the intensity or duration of symptoms of the common cold.
  • Question: Does taking echinacea reduce the intensity or duration of the common cold?
Step 2: Formulate a Hypothesis
  • Hypothesis: A proposed explanation for observed phenomena.
    • Hypothesis: Echinacea reduces the duration and severity of the symptoms of the common cold.
    • Null hypothesis: Echinacea has no effect on the duration or severity of the symptoms of the common cold.
Step 3: Devise a Testable Prediction
  • Prediction: If echinacea reduces the duration and severity of the symptoms of the common cold, then individuals taking echinacea should get sick less frequently than those not taking it, and when they do get sick, their illness should not last as long.
Step 4: Conduct a Critical Experiment
  • Experimental Setup:
    • 437 volunteers divided into four groups.
    • Groups 1 & 2: Echinacea before and after exposure.
    • Groups 3 & 4: Placebo or Echinacea only after exposure.
  • Treatment:
    • Groups 1 and 2 receive tablets for seven days longer than groups 3 and 4, in order to determine if treatment prior to exposure has any effect on the development or duration of symptoms.
    • Groups 1 & 3: Placebo after exposure to cold virus
    • Groups 2 & 4: Echinacea after exposure to cold virus
Step 5: Draw Conclusions, Make Revisions
  • Results:
    • Individuals from all four groups are equally likely to develop a cold.
    • Cold symptoms lasted for the same amount of time in all groups.
    • Echinacea had no effect on the duration or severity of the cold.
  • Further Experimentation:
    • Alter the amount of echinacea given to subjects.
    • Alter the length of time subjects receive the echinacea treatment.
  • Importance of Revision: Scientific thinking helps us understand when we should change our minds.

Basic Science

  • Deals with living organisms and how they interact with each other and their environment.
  • Biology as a separate science was developed in the nineteenth century.
Historical Figures
  • Robert Hooke (1635-1703)
  • Anton van Leeuwenhoek (1632-1723)

Main Fields of Biology

  • Botany: The study of plants.
  • Zoology: The study of animals.
  • Microbiology: The study of microscopic organisms.
  • Bacteriology: The study of bacteria.
  • Virology: The study of viruses.
  • Mycology: The study of fungi.
  • Entomology: The study of insects.
  • Ornithology: The study of birds.
  • Modern biology

Need for Energy

  • Every living organism needs energy to run many activities.
  • Sun is the universal energy source.
Energy Flow
  1. Primary Producers: Plants and Green organisms produce food from the sun.
  2. Primary consumers: Animals and non-green organisms get food from Primary producers.
  3. Secondary consumers: Get food from both Producers and Primary consumers.
  4. Tertiary consumers: Lives on primary and secondary consumers.

<br/>TertiaryConsumers:1 kcalSecondaryConsumers:10 kcalPrimaryConsumer:100 kcalProducers:1,000 kcal<br />\newline Tertiary Consumers: 1 \text{ kcal} \newline Secondary Consumers: 10 \text{ kcal} \newline Primary Consumer: 100 \text{ kcal} \newline Producers: 1,000 \text{ kcal}

Energy Cycle
  • Photosynthesis
  • Movement
  • Growth & development
  • Repair and maintenance
  • Response to stimuli
  • Variations and Adaptation
  • Reproduction
  • Metabolism

Movement

  • Animal: Most obvious/visual.
  • Plant:
    • Opening of buds.
    • Turning of leaves toward the sun.
    • Mimosa pudica (the sensitive plant).
  • Locomotion: Self-propulsion by the organism.
    • Swimming, running, flying, walking, etc.
    • Microorganisms also can propel by their own locomotion mechanism.
    • Any change of location is not locomotion. e.g., wind moves the branches of trees!

Cellular Structure & Organization

  • All Living things are made up of CELLS.
Cell Components
  • Cell wall, Cell Membrane,Mitochondrion Nucleolus, Nucleus, Nuclear Membrane Chloroplast, Cytoplasm Vacuole ,Centrosome, Rough ER, Smooth ER,lysosome,Golg vesicles ,rough ER (endoplasmic reticulum) ,smooth ER (no ribosomes) ,Amylosplast; cell (plasma) membrane,
Protoplasm
  • Complex mixture of substances.
  • All living cells have Protoplasm.
  • Made up of carbohydrates, fats, proteins, water, etc.
  • Ensures the living condition.
  • Composition is different in different organisms.
  • Protoplasm differs from one part to another even in the same organism --> always changing.

Growth & Development

Growth
  • Getting larger is not only the Growth.
  • By organizing materials, living things make a special kind of protoplasm, reproduce cells/increase the cell number, goes from one state to another.
Development
  • A series of changes that take place as an organism grows toward its final form.
  • By development, an organism becomes a unique living thing with specialized parts and different from others.

Maintenance & Repair

  • Part of growth and development.
  • Appears to have stopped growth but the system runs as 'maintenance and repair.'
  • Examples:
    • Replacing dead skin cells.
    • Healing of cut fingers.
    • Tail recovery of house lizard.

Reproduction

  • Only living things can produce offspring similar to themselves.
  • Process can be different:
    • Laying eggs.
    • Giving birth.
    • Plant seeds develop to plants, etc.
  • Law of nature: "life produces life" & "like produces like"
Life Span
  • Varies in organism to organism.
  • Examples:
    • Human: ~70 years.
    • Horse: 30 years.
    • Plants: 10/12/100/1000 years.
  • Limited life span → continued offspring → Reproduction.
  • Energy Requiring process.

Response to Stimuli

  • Irritability: Response to certain stimuli.
  • Animal:
    • Have nervous system.
    • Use Eyes, nose, ear to response.
  • Plants:
    • Do not have nervous system.
    • Slow response to light, oxygen, nutrient, etc.
  • Microorganisms:
    • Response to nutrients, environments.
    • Even single-celled organisms can respond.
  • Coordination: Doing the right thing at the right time.
  • Behavior: Change to a stimuli, in a certain pattern

Variation and Adaptation

  • Variation: Changes occur as a result of characteristic.
    • Most variations do not affect an organism's chances of survival.
    • Give an organism a better chance of surviving in a changing environment.
  • Adaptation: The process by which a certain type of organism becomes better suited to survive in its environment.
    • e.g.: Hibernation, Mimicry (The viceroy butterfly mimics the monarch butterfly by coloration. The monarch butterfly has a bitter taste to predators and predators avoid them.

Metabolism

  • The exchange of matter and energy between the organisms and within an organism.
  • Metabolism is the sum of all the processes occurring in an organism, including:
    • Ingestion
    • Digestion
    • Assimilation
    • Respiration
    • Excretion
Metabolic Phases
  1. Anabolism: Building up
  2. Catabolism: Breaking down

Scopes of Biology

  • The fields within biology are further divided based on the scale at which organisms are studied and the methods used to study them.
    • Fundamental chemistry of life
    • Complex interactions of systems of biological molecules
    • Basic building block of all life, the cell
    • Interrelation between various organisms and their environment
Specific Fields
  • Biomedical Engineering: Blending of engineering principles and design concepts with medicine and biology for healthcare purposes.
  • Veterinary medicine: Deals with the prevention, diagnosis, and treatment of diseases of animals.
  • Forensic Science: Involves investigating a crime with the help of applying scientific principles.
  • Bioinformatics: An interdisciplinary field that develops methods and software tools for understanding biological data. It combines computer science, statistics, mathematics, and engineering to study and process biological data.