Geological Time Periods & Evolutionary Events

Geological Time Periods & Evolutionary Events

• Precambrian defines the age of the late Precambrian
• Cambrian Explosion: marks the emergence of most major animal groups
• Paleozoic Era: The era of "old life"
• Paliozoic Era: The time when most marine invertebrates and early vertebrates appeared
• Mesozoic Era: The era of "middle life" and the golden age of dinosaurs
• Cretaceous Period: Dinosaurs reached their peak in size and distribution during this period
• Mass Extinction: When many or even most species abruptly disappear on Earth
• Adaptive Radiation: Adaptation that leads to a wide variety of offspring
• Cenozoic Era: the era of "modern life"

Taxonomy & Classification

• Taxonomy is the science of classifying organisms
• Linnaean classification: Classification system that was created in the 1700s
• Binomial nomenclature: Is the system on which modern classification systems are based
• Taxa: classification levels or groups
• Domain: The largest and most inclusive taxon, even larger than the kingdom
• Kingdom: The second most inclusive grouping
• Clade: Is the largest and most exclusive grouping, including a common ancestor and all descendants
• Genus: A grouping of closely related species
• Phylogeny: Represents evolutionary relationships
• Phylogenetic tree: Is a diagram that shows evolutionary relationships

Evolutionary Theories & Scientists

• Evolution: Change in species over time
• Natural selection: The process where species adapt to their environment
• HMS Beagle: The ship Darwin served on as a naturalist
• Galápagos Islands: Darwin observed finches and developed his theory here
• Malthus: Argued that human populations grow faster than available resources
• Lamarck: Argued that evolution occurs due to acquired traits
• Artificial selection: When humans select traits in organisms
• Darwin: Developed the theory of natural selection
• Inheritance of acquired characteristics: Idea that traits can be passed within an organism's lifetime
• Fitness: An organism's ability to survive and produce fertile offspring

Evolutionary Evidence & Processes

• Fossils: Preserved remains or evidence of past life
• Paleontologist: Scientists who locate and study fossils
• Comparative anatomy: Shows how organisms are related by descent from a common ancestor
• Homologous structures: Structures are similar in related organisms due to inheritance from a common ancestor
• Vestigial structure: Structures remain in unrelated organisms with no real function
• Embryology: Study of similarities and differences in embryos of different species
• Comparative embryology: The study of similarities in the structures of different species
• DNA sequences: Considered the strongest evidence for evolution
• Biogeography: The study of where plants and animals live and why
• Adaptive radiation: The process when a single species evolves into many new species

Key Biological Concepts

• Autotrophic: organisms make their own food
• Heterotrophic: Getting nutrition from other plants, animals, or related sources
• Earth's age: Earth formed 4.5 billion years ago
• Evolutionary order: Organic molecules → Prokaryotic cell → Eukaryotic cell → Photosynthesis
• LUCA( Last Universal Common Ancestor): A single celled organism dated to 3.5-4 billion years ago
• Fossils: Organisms that are quickly covered by sediments
• Relative dating: Determining whether a fossil is older than another rather than the exact age
• Molecular Clocks: Uses DNA or protein sequences to estimate divergence between species
• Phylogeny: Evolutionary history of a group of organisms
• Biological Classification: Kingdom → Phylum → Class → Order → Family → Genus → Species
• Taxonomy: The "father of taxonomy" is Carl Linnaeus
• Domains of life: Bacteria, Archaea, and Eukarya
• Binomial Nomenclature Example: Homo sapiens (humans), Panthera tigris (tiger), Canis lupus (wolf)

Structures: Homologous vs Analogous vs Vestigial

• Homologous: Same structure, different function (e.g., human arm & whale flipper)
• Analogous: Same function, different structure (e.g., bird wing & insect wing)
• Vestigial Structures: Body parts that have lost their original function and are often reduced in size; examples: Human tailbone, appendix, wisdom teeth

Evolution and History of Life

• Approximately 4.5 to 4.6 billion years ago, the Earth formed
• Initially, Earth was molten
• The early atmosphere consisted of volcanic gases
• Cloud formation and rainfall led to the formation of oceans
• The first organic molecules appeared, which led to prokaryotic cells
• Eukaryotic cells developed through endosymbiosis
• Multicellular organisms diversified, leading to the Paleozoic, Mesozoic, and Cenozoic Eras

First Organic Molecules & First Cells

• Miller and Urey Experiment simulated early Earth conditions and produced organic molecules
• RNA World Hypothesis: RNA may have been the first genetic material before DNA
• First cells: Simple prokaryotic-like cells
• LUCA (Last Universal Common Ancestor): Origin of all modern life, existing ~3.5 billion years ago
• Photosynthesis evolved, increasing oxygen levels, leading to cellular respiration

Evolution of Eukaryotes & Geological Time Periods

• Endosymbiotic Theory: Large prokaryotic cells engulfed smaller ones
• This evolved into mitochondria and chloroplasts
• Precambrian: Earth's earliest period, before 541 million years ago
• Paleozoic Era: Explosion of marine life
• Mesozoic Era: Age of dinosaurs
• Cenozoic Era: Age of mammals, human evolution

Systematics

• Systematics: Study of organism classification and related evolutionary relationships
• Combines taxonomy (naming organisms) and phylogenetics (evolutionary history)
• Uses molecular data, fossils, and morphology to classify organisms

Cladistics & Cladogram

• Cladistics: A classification method based on common ancestry
• Organisms are grouped into clades
• Each clade includes a common ancestor and all its descendants
• Uses shared derived traits to determine evolutionary relationships
• Cladogram: A tree-like diagram showing evolutionary relationships
• Represents how species diverged from common ancestors
• Each branch point represents a common ancestor

Bahay Kubo Scientific Names

These are the scientific names of vegetables and fruit

System of Classification & Dichotomous Key

• Develop by Carolus Linnaeus
• Uses hierarchical classification: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
• Binomial nomenclature: Assigns each species a unique two-part name
• A Dichotomous Key is a tool used for identifying organisms

Theory of Evolution: Evidence & Relationships

• Fossils: Preserved remains or traces of organisms
• Fossil Record: Shows how species have changed over time
• Relative Dating: determines if a fossil is older or younger than another
• Absolute Dating: Uses radioactive isotopes to determine fossil age
• Molecular Clocks: DNA sequences estimate when species diverged
• Comparative Anatomy: Similarities in structures indicate common ancestry
• Homologous structures: Similar structures from common ancestors
• Vestigial Structures: Reduced or unused structures
• Comparative Embryology: Similarities in early development
• Biogeography: Study of species distribution

Mechanisms of Evolution & Linnaean Classification

• Natural Selection: Favorable traits increase survival and reproduction
• Adaptive Radiation: One species evolves into multiple new species
• Mass Extinctions: Events causing abrupt species loss
• Developed by Carolus Linnaeus in the 1700s
• Organisms grouped by similarities into taxa: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Nomenclature & Phylogeny and Cladistics

• Two-part scientific name: Genus species (e.g., Homo sapiens)
• Phylogenetic Tree: Shows evolutionary relationships
• Cladograms: Group organisms by common ancestry

Charles Darwin & Evolutionary Theory

• Observed species variations during his voyage of the HMS Beagle and visited the Galápagos Islands
• Natural Selection: Variation exists within populations, More offspring are produced than survive, favorable traits increase survival, and over generations, populations evolve
• Jean-Baptiste Lamarck: Proposed (incorrectly) traits acquired in life are inherited
• Charles Lyell: geologists proposed slow geological changes
• Thomas Malthus: Human population growth exceeds resources, leading to competition
• Alfred Russel Wallace: Independently developed a similar theory of evolution

Kingdoms of Life & Taxonomy

• Five (or six) kingdoms classify life into: Bacteria Unicellular prokaryotes (e.g., E. coli), Archaea Unicellular prokaryotes in extreme environments, Protists Mostly unicellular eukaryotes (e.g., algae, protozoa), Fungi Decomposers (e.g., mushrooms, yeast), Plantae Multicellular, autotrophic (e.g., trees, flowers), Animalia Multicellular, heterotrophic (e.g., humans, insects)
• Taxonomy: Science of classifying and naming Organisms
• Credited to Carolus Linnaeus who introduced binomial nomenclature system

Organism Classifications & Domains of Life

• Classification helps organize biological diversity and understand evolutionary relationships
• Organisms are classified based on shared characteristics
• A standardized naming system avoids confusion caused by common names
• Hierarchy of Classification (from broadest to most specific): Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species; a mnemonic is Does King Philip Come Over For Great Soup
• Bacteria is a unicellular prokaryotic organism
• Archaea are unicellular prokaryotes that live in extreme environments
• Eukarya are organisms with eukaryotic cells; these includes Protists, Fungi, Plants, and Animals

Rules for Binomial Nomenclature

• Organisms are given a two-part Latin name: Genus species
• Genus is capitalized, species is lowercase
• Name must be italicized (or underlined when handwritten)
• e.g., Homo sapiens (humans), Panthera tigris (tiger)