Introduction to Biology

• Biology is the scientific study of life and living organisms.
• Early and modern beliefs exist regarding the origin of life.
• All living things share common characteristics.
• Photosynthesis and cellular respiration are interconnected processes, cycling energy and matter to sustain life.

Branches of Biology

• Microbiology: Study of microorganisms.
• Botany: Study of plants.
• Zoology: Study of animals.
• Taxonomy: Naming and classifying organisms.
• Cytology: Structure and function of cells.
• Embryology: Formation and development of organisms.
• Anatomy: Structure and parts of organisms.
• Physiology: Function of living organisms and their parts.
• Biochemistry: Biochemical compositions of living things.
• Genetics: Heredity and variation.
• Evolution: Origin and differentiation of various organisms.
• Ecology: Relationships of organisms in their environment.
• Molecular Biology: Molecules that make up the cells of living organisms.
• Genomics: Genetic material (genome) of an organism.
• Proteomics: Proteins in a living organism.
• Immunology: Immune system and immunity.
• Bioinformatics: Biological data using computer programs.
• Virology: Viruses and virus-like agents.

Early Beliefs About the Origin of Life

• Theory of Spontaneous Generation (Abiogenesis):
  • Life could appear from nonliving material, first proposed by Aristotle in the 14th Century.

Experiments Disproving Spontaneous Generation

• Redi’s Experiment (1668):
  • Francesco Redi demonstrated that maggots in decaying meat arise from eggs laid by flies.
  • Life arises from living matter.
• Needham’s Experiment (1748):
  • John Needham's experiment with heated broth became cloudy and full of microorganisms.
  • Heating was insufficient to kill all microorganisms.
• Spallanzani’s Experiment (1767):
  • Lazzaro Spallanzani showed that life occurred from something that entered the unsealed flask.
• Pasteur’s Experiment (1861):
  • Louis Pasteur demonstrated that new bacteria appear only when produced by existing bacteria using boiled sugar solution in flasks with long necks.

Current Beliefs About the Origin of Life

• Divine Creation (Creationism):
  • Life came from a divine being over a six-day period.
• Spontaneous Origin:
  • Life evolved from inanimate matter facilitated by molecules and energy sources like lightning or geothermal activity.
    • Includes the Theory of Primordial Soup and Deep-sea vent Theory.
  • Miller-Urey Experiment: Recreated early Earth conditions to form organic molecules.
• Panspermia Theory:
  • Svante Arrhenius proposed that life came from meteorites or cosmic dust.
  • A meteorite found in Antarctica may have originated from Mars.

Characteristics of Life

• Metabolism:
  • Chemical reactions inside cells allow organisms to break down food, send nutrients, remove waste, transform energy, and synthesize new chemicals.
• Homeostasis:
  • Maintaining a stable internal environment through processes like breathing, waste elimination, and thirst regulation.
• Adapting and Evolving:
  • Adaptation through evolution allows life forms to respond to the external environment and change heritable traits.
• Response to Stimuli:
  • Example: Phototropism - a plant's response to light.
• Reproducing and Continuing Life:
  • Growth and development occur, with organisms reproducing copies of themselves.
• Reproduction:
  • Organisms reproduce at different rates (e.g., mayflies live for 1 day, Aldabra tortoises for 120 years).
• Heredity:
  • Characteristics are transferred through Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA).
• Biotechnology:
  • Combines biology and technology to improve the quality of life.

Basic Unit of Life: Cell

• Robert Hooke (1665):
  • First viewed cells in cork, describing them as tiny, empty compartments.
  • Coined the term "cell" referring to the cellulose small rooms within the cork.
• Matthias Jacob Schleiden (1838):
  • Concluded that different parts of plants are made up of cells, which are the basic units of organisms.
• Theodor Schwann (1839):
  • Showed that animal tissues are also made up of individual cells.
• Rudolf Virchow (1855):
  • Stated that new cells form from previously existing cells ("omnis cellula e cellula").

The Cell Theory

• All organisms are made up of one or more cells.
• A cell is the basic unit of an organism.
• A cell arises from pre-existing cells.

Characteristics of Cells

• Cells are the basic structural units of all living things.
• Cells are made up of carbohydrates, lipids, proteins, nucleic acids, salts, and water.
• Cells store energy in the form of adenosine triphosphate (ATP).
• Unicellular organisms are single-celled (e.g., Amoeba).
• Multicellular organisms have specialized cells (e.g., animal and plant cells).

Basic Functions of Life

• Respiration: Metabolic reactions and processes.
• Regulation: Control and coordination of body activities.
• Reproduction: Production of new organisms.
• Excretion: Removal of waste.
• Growth: Increase in size of organism.
• Nutrition: Process by which organisms take in food.
• Transport: Absorption and circulation of needed materials.
• Synthesis: Production of complex substances from simpler ones.

Photosynthesis and Cellular Respiration

• Respiration is a set of metabolic reactions and processes.

Perpetuation of Life

• Classification of Animals:
  • Vertebrates: Animals with a backbone.
    • Warm-blooded: mammals and birds.
    • Cold-blooded: fish, reptiles, and amphibians.
  • Invertebrates: Animals without a backbone.

Reproduction Types

• Asexual Reproduction:
  • Involves a single parent.
  • Offspring are exact genetic copies ("clones").
• Sexual Reproduction:
  • Involves two parents.
  • Combines two gametes (sex cells).
• Chromosome Numbers:
  • Chicken and Cow: 39 pairs.
  • Monkey: 24 pairs.
  • People: 23 pairs.
  • Fly: 4 pairs.
  • Banana: 11 pairs.

Asexual Reproduction Types

• Fragmentation:
  • Pieces of the parent break off and develop into new animals (e.g., Planaria, Sponges, Sea stars).
• Binary Fission:
  • Separation of the parent cell into two new daughter cells (e.g., some bacteria, amoeba, euglena).
• Budding:
  • A new organism develops from an outgrowth or bud on the parent's body (e.g., Hydra).
• Parthenogenesis:
  • Development of a zygote from an unfertilized egg (virgin birth) (e.g., Komodo dragon, zebra shark).

Sexual Reproduction Characteristics

• Fusion of two gametes from two parents.
• Results in genetically diverse offspring.
  • Oviparous: Egg-laying animals.
  • Viviparous: Producing living young.

Animal Reproduction Summary

• Animals can reproduce sexually and asexually.
• Asexual reproduction requires one parent; sexual reproduction requires two parents.
• Examples of asexual reproduction: Honey bees, hydra, amoeba, and flatworms.
• Examples of sexual reproduction: Giraffe, cats, eagles, salmon, and cattle.

How Animals and Plants Survive

• Metabolism:
  • Anabolism: Simple to complex (e.g., photosynthesis).
  • Catabolism: Complex to small (e.g., cellular respiration).

Digestive System

• Breaks down food into nutrients.
  • Ingestion: Intake of food.
  • Digestion: Breakdown of food into simpler substances.
  • Absorption: Taking nutrients into cells.
  • Elimination: Removal of indigestible wastes.
  • Gastroesophageal Reflux Disease (GERD): Stomach acid flows back into the esophagus.

Respiration vs Breathing

• Breathing: Physical process of inhaling oxygen and exhaling carbon dioxide in the lungs.
• Respiration: Biochemical process in cells (mitochondria) where oxygen breaks down glucose to produce energy (ATP).
• Gas exchange system brings in oxygen, removes carbon dioxide.

Types of Gas Exchange Systems

• Skin Respiration:
  • (Integumentary or cutaneous respiration) in amphibians and worms in moist environments.
• Gills Respiration:
  • Aquatic animals use gills for gas exchange.
• Tracheal Respiration:
  • Occurs through the trachea.
  • Spiracle: small external opening of a trachea (e.g., insects, centipedes, arachnids).
• Lung Respiration:
  • Land animals use lungs (e.g. divided into small chambers).
  • Cystic Fibrosis (CF): Increased scarring of the lungs due to lung infections from thick mucus.
  • E-cigarette or Vaping-Associated Lung Injury (EVALI): Serious lung disease from vaping.

Circulatory System

• The body’s transport system.
  • Consists of the heart, blood vessels (arteries, veins, capillaries), and blood.

Circulatory Types

• Open Circulatory System:
  • Most invertebrates use open-ended vessels.
  • Blood and interstitial fluid mix.
• Closed Circulatory System:
  • Complex invertebrates and vertebrates.
  • Blood is separated from interstitial fluid.
  • Atherosclerosis: Buildup of fat and cholesterol inside arteries, leading to reduced blood flow.

Urinary System

• Filtration: Kidneys filter waste from the blood.
• Reabsorption: Kidneys reabsorb useful substances like water and glucose.
• Secretion: Kidneys add extra waste into the forming urine.
• Excretion: Urine is sent out of the body through the bladder and urethra.
  • Urinary Tract Infection (UTI): Infection in the urinary system due to bacteria.

Immune System

• White blood cells, skin, lymph.
  • Pathogens: Disease-causing agents.
  • Immunity: Ability of the body to resist infection.
• Four symptoms of injury: Redness, pain, swelling, heat.
• Antigen: Protein substance that stimulates the immune system.
  • Acquired Immunodeficiency Syndrome (AIDS): Caused by HIV, weakens the immune system.

Endocrine System

• Produces and releases hormones into the bloodstream.
• Hormones control growth, metabolism, mood, and reproduction.

Main Parts of the Endocrine System

• Pituitary Gland: "Master gland" that controls other glands.
• Thyroid Gland: Regulates metabolism and energy.
• Adrenal Glands: Help with stress and energy (release adrenaline).
• Pancreas: Controls blood sugar with insulin.
• Ovaries/Testes: Control reproductive hormones.
  • Polycystic Ovary Syndrome (PCOS): Hormonal disorder causing irregular periods and fertility problems

Nervous System

• The body's control center for sending/receiving signals.
  • Central Nervous System (CNS): Brain & Spinal Cord (processes and sends information).
  • Peripheral Nervous System (PNS): Nerves connecting the CNS to the rest of the body.
    • Schizophrenia: Mental disorder affecting thoughts, emotions, and behavior.

Muscular System

• Responsible for movement, posture, and body functions.
  • Skeletal Muscles: Attached to bones; control body movement (voluntary).
  • Cardiac Muscle: Found only in the heart; helps pump blood (involuntary).
  • Smooth Muscles: Found in organs; help digestion and other functions (involuntary).
• Gluteus Maximus (butt muscle) is the largest muscle in the body.
• Stapedius (ear) is the smallest muscle.
• Eye muscles move the fastest.
• Heart muscle beats about 100,000 times daily.

Skeletal System

• Framework of the body (bones, joints, cartilage) for support, protection, and movement.
• Helps in blood cell production and mineral storage.
  • Bones: Hard structures making up the skeleton.
  • Joints: Connect bones and allow movement.
  • Cartilage: Soft tissue cushioning joints.
• Snakes have the most bones.
• Newborns (humans): ~300 bones; Adult humans: 206 bones.
• Blue whale’s jawbone is the largest bone of any animal.
• Femur (thigh bone) is the largest/strongest bone in the human body.
• Staples (ear bone) are the smallest bones of mammals.

Plant Organ System and Metabolic Processes

• Plants are producers, creating their own food through photosynthesis.
• Humans and animals are consumers that depend on plants.

Plant Organ Systems

• Root System
• Shoot System
• Root System: ( underground )
  • Anchors the plant.
  • Absorbs water and nutrients.
  • Stores food.

Parts of the Root System

• Primary Root: The main root that grows downward.
• Secondary Roots: Branch out from the primary root.
• Root Hairs: Increase surface area for absorption.
• Root Cap: Protective layer at the tip.
• Shoot System: ( above-ground )
  • Stems.
  • Leaves.
  • Flowers.
  • Buds.
  • Facilitates Photosynthesis, reproduction and support.

Parts of the Shoot System

• Stem: Supports the plant, conducts water and nutrients.
• Leaves: Site of photosynthesis and gas exchange.
• Flowers: Reproductive structure.
• Buds: Develop into new shoots, leaves, or flowers.

Noteworthy Plants

• The Oldest Tree
  • Methuselah is a 4,851 years old great basin bristlcine pine (pinus longaeva) tree growing high in the white mountains of inyo county in eastern California
• The fastest growing plant
  • bamboo can grow up to 35 inches (91 cm) in a single day under the right conditions
• The world’s largest Flower
  • The rafflesia arnoldii, also called the corpse flower can grow up to 3 feet (1 meter) in diameter and smells like rotting flesh

Animals and Plants Overview

• Animals and plants have different organ systems for survival.
• Animal systems support movement, energy production, and bodily functions.
• Plants have root and shoot systems for water/nutrient transport, photosynthesis, and support.