Intro to Biology Concepts

• Biology is the scientific study of living things, both alive and dead (fossils).

Main Branches of Biology

• Zoology
• Botany
• Microbiology
• Virology
• Parasitology
• Mycology
• Entomology
• Marine Biology
• Ecology
• Evolutionary Biology
• Anatomy
• Physiology
• Immunology
• Neuroscience
• Cell Biology
• Molecular Biology
• Genetics
• Biochemistry
• Biotechnology
• Paleontology

Specialized Fields within Biology

• Biophysics.

• Astrobiology.

• Developmental Biology.

• Biogeography.

• Systems Biology.

• Synthetic Biology.

• Taxonomy.

• Chronobiology.

• Biometrics.

• Bioinformatics.

• Pharmacology.

• Toxicology.

• Biostatistics.

• Cryobiology.

• Ornithology.

• Herpetology.

• Ichthyology.

• Limnology.

• Ethology.

• Oncology.

• Dermatology.

• Pathology.

• Agricultural Biology.

• Radiobiology.

• The goal of biology is discovering and understanding the underlying unity and diversity of the complex processes that make up life.

Distinguishing Living Things from Nonliving Things

• Cellular Structure and function
• Growth
• Development
• Metabolism
• Homeostasis
• Response to stimuli
• Reproduction
• Adaptation
• Evolution
• Limited lifespan

All Living Things are Made of Cells

• Latin "cellula" translates to "small room"
• A cell is a small membrane-bound unit filled with a concentrated aqueous solution of chemicals with reproduction capacity.
• All cells have similar cellular structures, including a lipid-containing membrane, organelles, etc

All Living Things Have Genetic Information

• Genetic information is stored in DNA (deoxyribonucleic acid).
• DNA molecules are composed of four different subunits called nucleotides.
• All DNA in a cell constitutes its genome.
• A segment of DNA that contains the instructions for making a protein or an RNA is called a gene.

All Living Things Use Genetic Information the Same Way

• Genetic information flows from DNA to RNA (transcription) and from RNA to protein (translation).
• They use a universal genetic code to build proteins from their genomic information.

All Living Things Grow

• Growth refers to the increase in mass and size of a body or organs.
• The mass of an organism increases by an increase in cell number and/or cell size.

Multicellular Development

• During development, specialized cells appear from non-specialized cells.
• Cell differentiation is the process of specialization.
• Cell differentiation involves changes in gene expression.

All Living Things Extract Energy

• Living organisms obtain nutrients from their environment.
• Biochemical reactions break down nutrient molecules.
• Chemical breakdown produces building blocks for structures and energy for cell works (mechanical, biochemical, and electrical).

All Living Things Regulate Internal Environment

• Maintenance of a constant internal environment is called homeostasis.
• Homeostasis requires cell activity regulation, such as glycemia and insulin signaling.
• Sensory, effector, and signaling mechanisms help integrate information
• The main information systems of animals are the nervous, hormonal, and immune systems.
• Living things use chemical and electric signals to process information.

Response to Stimuli

• All living things respond to their environment and reproduce

Genetic Change

• Mutations are permanent changes in DNA sequence.
• Most mutations are harmful, causing cancer, disorders, and deformities
• Some mutations are beneficial
  • Polyploidly- organisms with extra sets of chromosomes
  • Resistance to chemicals and diseases
  • Evolution

All Living Things Evolve

• Mutations lead to differences among individuals in a population.
• These differences affect their chances of survival and reproduction.
• The most adapted individuals survive and reproduce (natural selection).
• Mutations and natural selection account for the evolution of biodiversity on Earth.

Common Ancestry

• These similarities indicate that the diverse organisms alive today all originated from one life form.

Tracing Evolutionary History

• Identification, analysis, and quantification of similarities and differences among species help construct phylogenetic trees.
• Phylogenetic trees display the evolutionary history of different groups of organisms. Each species is given a binomial scientific name
• The first part indicates the genus, and the second part, the species (e.g., Homo sapiens).
• Up to 100 million species are estimated to live on Earth.
• Earth formed around 4.6 billion years ago (ya)
• Life appeared 600 million years later (~4 billion ya)
• Photosynthesis: 2.5 billion ya
• Eukaryotic cells: 1.5 billion ya
• Multicellular organisms: 1 billion ya
• Modern humans: 500,000 ya

Chemical Evolution

• The critical step for the evolution of life was the appearance of nucleic acids.
• Nucleic acids could reproduce themselves and serve as templates for the synthesis of proteins.
• Fatty acids make spherical structures called liposomes.
• In a primordial ocean, membranous structures could have enveloped complex biological molecules.

Photosynthesis

• Photosynthesis allows some organisms to capture energy from the Sun.
• Photosynthesis led to the accumulation of O2 in the atmosphere
• Aerobic metabolism is far more efficient than anaerobic metabolism in extracting energy from nutrient molecules.
• Ozone creation and the appearance of life on land occurred 500 million years ago

Eukaryotic Cells Evolution

• Nuclear membranes and the endoplasmic reticulum (ER) may have evolved through invagination of the plasma membrane.
• Mitochondria are probably ancient aerobic prokaryotes engulfed by a pre-eukaryotic cell.
• Chloroplasts originated when a eukaryotic cell with mitochondria engulfed a photosynthetic prokaryote.
• Endosymbiosis is likely responsible for the appearance of mitochondria and chloroplasts.

Multicellular Evolution

• Single-celled organisms began to form colonies or groups, allowing cells to work together and share resources, which is Aggregation.
• Specialization: Within these colonies, cells started to specialize in different functions.

Three Domains of Life

• Discoveries in biology can be generalized from model syste

Scientific Investigation

• Observation and quantification are important skills in science.
• Scientific methods combine observation, experimentation, and logic(inductive/deductive logic).
• Good experiments can falsify hypotheses (controlled/comparative experiments).
• Statistical methods are essential scientific tools (null hypothesis, probability of error).