Biology Chapter: Classification of Living Organisms

Biology Exam Review

• Ian Hobdari is the instructor
• The review covers lessons 1-8 for Diversity of Living Things, lessons 1-8 for Genetics, lessons 1-6 for Evolution, and lessons 1-4 for Animal Systems.

Diversity of Living Things - Lesson 1

• Biodiversity: The variety of life on Earth
• Characteristics of Living Things: Made of cells, respond to their environment, reproduce, adapt to surroundings, grow and develop, use and need energy (remembered by "MR RAGU")
• Biological Species: A group of organisms capable of interbreeding and producing fertile offspring. Labradoodles can produce offspring, while a zorse (zebra + horse) cannot
• Taxonomy: The branch of biology that classifies organisms and assigns them universally accepted names.
• Three Levels of Biodiversity: Genetic diversity, species diversity, and ecological diversity
• Threats to Biodiversity: Habitat loss, invasive species, population decline, pollution, and over-exploitation

Darwin's Theory of Evolution

• Organisms produce more offspring than can survive: Intense competition for resources
• Individuals best suited to their environment: Survive and reproduce
• Species change over time: "Natural selection"
• Early attempts at classification: Organisms grouped by plants and animals, then by land, air, or water dwellers
• Linnaeus's system: Classification based on structural similarity
• Binomial nomenclature: System of assigning two-part scientific names
• Modern taxonomy: Based on evolutionary relationships (phylogeny) represented by phylogenetic trees.

Darwin's System of Classification

• Homologous structures: Similar structure, different function (evidence of common ancestry)
• Analogous structures: Different structure, similar function
• Vestigial structures: Reduced structures with no apparent current function
• Three ways to determine if organism are similar: biochemical similarities, genetic similarities, and embryological similarities

Modern Taxonomy

• Domains: Eukarya, Bacteria, Archaea
• Kingdoms: A broader level than Domain

Binomial Nomenclature

• Two-word system using Latin
• First word is the genus (capitalized) and second is the species (not capitalized)
• Ex: Tiger (Panthera tigris)

Modern Taxonomy

-Phylogeny is the evolutionary history of an organism
-Scientists construct a phylogenetic tree to show evolutionary relationships
-A phylogenetic tree is a family tree that shows evolutionary relationships thought to exist
among different groups of organisms

Modern Taxonomy-Cladistics

-Method of classifying organisms based on shared derived characters
-Shared derived characters are “evolutionary innovations” arising in organisms over time
-Cladograms are diagrams showing evolutionary relationships among organisms

Domains and Kingdoms

• Monera kingdom: Bacteria and blue-green algae
• Six known kingdoms and three domains
• Archaebacteria, Eubacteria, Protists, Fungi, Plantae, Animalia -Kingdom comparisons would list each of these with characteristics such as cell type, cell organisation, and obtaining food

All Living Things

• Structure: Prokaryotic vs. Eukaryotic. Cell walls (thickness and rigidness), presence of chloroplasts
• Organization: Unicellular vs. Multicellular
• Food Getting: Autotrophs (make own food) vs. Heterotrophs (eat other organisms)

Viruses

• Non-living: Cannot perform required processes of life, only can reproduce within a host cell
• Structure: Nucleic acid (DNA or RNA) in core, surrounded by capsid (protein coat), some with outer envelope
• Replication: Lytic or lysogenic cycles -There are two different types of ways viruses can replicate within a host cell: the lytic cycle and the lysogenic cycle

Genetics - Lesson 1

• Genetics: The scientific study of genes, heredity, and genetic variations
• Trait: A characteristic of an organism
• Heredity: How information is passed on from one generation to the next
• Chromosomes: Molecules forming pieces in the nucleus of cells (DNA)

DNA Structure

• Nucleic acid molecules (DNA)
• DNA is made of pieces (genes) that code for proteins
• Stored in chromosomes located in the nucleus
• Composed of four nitrogen bases: A, T, C, G
• Form the backbone of a nucleic acid
• The four types of nucleotides occur in DNA -Adenine (A) -Cytosine (C) -Guanine (G) -Thymine (T).

Genes, Loci, and the Genetic Sequence

• The order of nitrogenous bases is a code (language)
• Code is read in sections (“genes”) by cell equipment; it creates proteins
• The location of a gene on a chromosome is called the locus (loci) of the gene
• Proteins are responsible for traits in organisms (eye color, height, etc).

The Cell Cycle

• Purpose: Create daughter cells
• Stages: G1, S, G2, mitosis, cytokinesis

Cell Division (Mitosis)

• Process: Ensures genetic continuity creating two identical cells from original
• Purpose: Creates two identical daughter cells, allowing for growth, tissue repair and maintenance

Apoptosis

• Programmed cell death
• Crucial for normal development and eliminating cells that have developed incorrectly or damaged cells

Mitosis - Lesson 2

• Prophase, Metaphase, Anaphase, Telophase
• Summary of mitosis phase, explaining what happens during each stage.

Chromosome vs Chromatid

• Explain the difference between chromosomes and chromatids
• Summary of Chromosome and Chromatid

Mutations

• Changes to genetic material: DNA
• Positive or negative impacts: On the organism and/or offspring
• Main source of genetic variability: Among species and individuals
• Types of mutations: Errors in DNA replication

Polygenic Traits

• Traits controlled by several genes (not just one)
• Examples: Hair, skin, eye and eye color, height
• Controlled by the expression of many genes, often on different chromosomes
• A combination of many genes combined result in a range of phenotypes

Sex Chromosomes

• Determine sex (example the X and Y chromosomes).
• Sex-linked traits show up more frequently in offspring of one sex
• Example traits: Red-green colorblindness, hemophilia, Duchene muscular dystrophy

Pedigrees

• Graphic representation of a family tree
• Tracks inheritance patterns of a particular trait
• Symbols: Male phenotypic sex, female phenotypic sex, affected trait by trait, undetermined sex,
• Identifies individuals, their relationship to each other and the trait under study.

Human Inheritance Patterns

• Can be autosomal (on non-sex chromosomes) or sex-linked
• Autosomal traits appear equally in both sexes
• Sex-linked traits often appear more often in one sex
• Important for tracking and understanding diseases, conditions and traits that are passed down generations

Population Genetics

• The study of genetic variations within populations
• Examines how the allele frequencies change over time due to mechanisms causing variations.
• Microevolution: Describes changes in allele frequency within a population
• Macroevolution: Describes major changes in organisms over time
• Important in explaining diversity in organisms

Mechanisms of Microevolution

• Natural selection: Organisms with favorable traits leave more offspring, thus passing those traits on.
• Mutation: Process that creates new alleles.
• Sex selection: Non-random mating preference
• Genetic drift: Random changes in allele frequency (especially pronounced in smaller populations).
• Gene flow: Movement of alleles from or to a population.

Natural Selection

• Variation in traits and competition
• Survival of the fittest
• Reproduction; Passing on traits

Types of Natural Selection

• Stabilizing selection: Favors intermediate traits & reduces extreme traits.
• Directional selection: Favors one extreme trait; Shifts population towards extreme traits.
• Disruptive/Diversifying selection: Favors two extremes traits; Creates a wider range of traits.

Forces of Microevolution: Mutation

• Random changes in an organism's DNA sequence
• Lead to variations in offspring
• Rate of mutations is low
• Can be beneficial, neutral, and/or harmful

Forces of Microevolution: Gene Flow

• Movement of alleles between populations
• Can introduce new alleles or change allele frequencies in the population(s)
• Influenced by migration

Forces of Microevolution: Genetic Drift

• Random change in allele frequency due to chance events
• More significant in small populations
• Examples: Bottleneck Effect (disasters reduce population size) and Founder Effect (small group migrating to new area)

Animal Systems - Lesson 1

• Key Concepts: Nutrients for energy, food processing, Digestive System, Gastrointestinal Tract
• Essential nutrients: Categories as Macronutrients (Carbohydrates, Protein, Fats, Water). Micronutrients (Vitamins, Minerals)
• Food Processing: Ingestion, Digestion, Absorption, Egestion stages
• Systems involved in food processing: Digestive system, circulatory system
• Essential role of water: Transport, lubrication, nutrient delivery
• Metabolic rate/calorie production: Cellular processes needing energy

Animal Systems - Lesson 2

• Digestive System: Organs & Pathways. Oral Cavity, Pharynx, Esophagus, Stomach, Small Intestine, Large Intestine, Rectum, Anus; Accessory organs: Pancreas, Liver, Gallbladder

• Digestion processes: Mechanical vs. Chemical.

Animal Systems - Lesson 3

• Circulatory System: Organs, Pathways & Functions. Heart, Blood vessels (Arteries, Veins, Capillaries), Blood (Plasma, Red Blood Cells, White Blood Cells, Platelets).
• Blood components: Function of each
• Blood Vessels: Structure, function of each

Animal Systems - Lesson 4

• Respiratory System: Organs, Pathways & Function. Nasal Cavity, Pharynx, Larynx, Trachea, Bronchi, Bronchioles, Alveoli.
• Process of breathing: Inhalation, Exhalation
• Gas exchange: External respiration, Internal respiration, Cellular respiration
• Respiratory Tract: Air passageways
• Anatomy of Larynx: Vocal cords
• Lower Respiratory Tract: Air passageways in the lungs

Test your knowledge on the classification of living organisms with this quiz. It covers various aspects such as kingdoms, domains, and characteristics of organisms. Perfect for students looking to reinforce their understanding of biology concepts related to living organisms.