Scientific Theories and Hypotheses

Exam 1 Study Guide

• Theory: A universal explanation for a wide range of phenomena
• Hypothesis: A tentative explanation for natural phenomena (an educated guess)
• Fact: A phenomenon with actual objective existence independent of human perceptions or interpretations.
• Law: A statement describing the relationship between two or more phenomena.
• Model: A representation of a phenomenon, emphasizing a specific aspect.
• Proof: In science, results of investigations either support or do not support a hypothesis; there's always room for alternative explanations consistent with data.
• Falsifiability: A necessary condition for scientific ideas; there must be a possibility to prove an idea wrong.
• Uniformitarianism: The present is the key to the past; the forces operating today also operated in the past.
• Catastrophism: The hypothesis stating that Earth's geological features were formed by sudden, violent events.
• Truth without certainty: Scientific explanations are the best based on available evidence but can be revised.
• Paradigm shift: A fundamental change in scientific understanding (e.g., from geocentrism to heliocentrism).
• Null hypothesis: A default assumption that nothing is happening (no effect, no difference). Used in hypothesis testing.
• Traditional classification: Groups organisms based on shared characteristics without necessarily considering evolutionary history.

Phylogenetic Systematics

• Phylogenetic systematics: Groups organisms based on shared derived characteristics and common ancestry
• Grades: Groups based on overall similarity rather than strict evolutionary relationships.
• Clades: Evolutionary groupings including an ancestor and all its descendants.
• Monophyletic: A group including an ancestor and all its descendants.
• Polyphyletic: A group not including the most recent common ancestor.
• Paraphyletic: A group including a common ancestor but not all its descendants.
• Ancestral characteristic: A trait inherited from a common ancestor.
• Apomorphy: A derived characteristic evolving within a specific group.
• Synapomorphy: A shared derived characteristic indicating common ancestry.
• Plesiomorphy: An ancestral characteristic retained in a group's descendants.
• Convergent characteristic: A trait evolving independently in unrelated lineages due to similar environmental pressures.
• Anapsid: Skull type with no temporal openings.
• Diapsid: Skull type with two temporal openings (dinosaurs).
• Synapsid: Skull type with one temporal opening.

Additional Anatomical Terms

• Tetrapoda: Four-limbed vertebrates (amphibians, reptiles, birds, and mammals).
• Amniota: Vertebrates with amniotic eggs (reptiles, birds, and mammals).
• Sauropsida: Group including reptiles and birds.
• Eureptilia: Advanced reptiles including diapsids.
• Lepidosauromorpha: Group including lizards, snakes, and tuataras.
• Archosauromorpha: Group including crocodiles, pterosaurs, and dinosaurs.
• Crurotarsi: Crocodile-line archosaurs with a specialized ankle joint.
• Ornithodira: Dinosaur-line archosaurs, including pterosaurs and dinosaurs.
• Dinosauria: The clade containing all dinosaurs.
• Saurischia: "Lizard-hipped" dinosaurs.
• Ornithischia: "Bird-hipped" dinosaurs.
• Manus: Hand
• Pes: Foot
• Tarsals: Ankle bones
• Metatarsals: Long foot bones connecting toes to the ankle.
• Carpals: Wrist bones
• Metacarpals: Long hand bones connecting fingers to the wrist.
• Phalanges: Finger or toe bones
• Digits: Fingers or toes.
• Crurotarsal ankle joint: Flexible ankle joint in crocodilian ancestors.
• Mesotarsal ankle joint: More rigid ankle joint found in dinosaurs.
• Bilateral symmetry: Body plan with two symmetrical halves.
• Radial symmetry: Body plan arranged around a central axis.
• Metamerism: Repeated body segments (e.g., vertebrae).
• Cephalization: Concentration of sensory organs at the head.
• Antorbital fenestrae: Skull openings in front of the eye (characteristic of archosaurs).
• Mandibular fenestrae: Skull openings in the lower jaw.
• Sacral vertebrae: Fused vertebrae in the pelvic region
• Glenoid fossa: Shoulder socket.
• Ball shaped femur head: Feature allowing a more upright stance.

Additional Dinosaur Classification and Concepts

• Ornithopoda: Bipedal or facultatively quadrupedal herbivores (e.g., Iguanodon).
• Thyreophora: Armored dinosaurs (e.g., Stegosaurus, Ankylosaurus).
• Marginocephalia: Dinosaurs with bony frills or thick skulls (e.g., Triceratops, Pachycephalosaurus).
• Hot Spots: Areas of volcanic activity independent of plate boundaries
• Plantigrade: Walking on whole foot (e.g., humans, bears)
• Digitigrade: Walking on toes (e.g., dogs, dinosaurs).
• Unguligrade: Walking on tips of toes (e.g., horses).
• Pubis, Ischium, Ilium: Major pelvic bones.
• Ilium: Uppermost, largest part of the pelvis connecting to vertebrae.
• Ischium: Lower, rear part of the pelvis.
• Pubis: Lower, front part of the pelvis.
• Prorotodactylus (Dinosauromorph): Early dinosauromorph with footprints suggesting upright walk.
• Eoraptor: An early dinosaur from Argentina.
• Prevailing Winds (Coriolis Effect): Earth's rotation causing moving air to curve.
• Rain Shadow: Dry conditions on the leeward (downwind) side of a mountain.
• Monsoons (Megamonsoons): Seasonal wind shifts causing heavy rainfall in some regions.
• Unidirectional Air Flow in Respiration: A specialized breathing system found in birds and some dinosaurs.
• Dinosaur Size and Scaling: Larger size requires stronger bones and better metabolism.
• Scallling laws: larger volume grows faster than surface area in animals, impacting evolutionary traits, heat regulation, metabolism, etc.

Additional Topics

• Wave interference: Interaction of overlapping waves, leading to constructive or destructive effects.
• Photoelectric effect: Emission of electrons from a material when light shines on it, supporting quantum mechanics.
• Heisenberg uncertainty principle: The inability to precisely know both the position and momentum of a particle simultaneously.

Additional Classification and Evolutionary Topics

• Traditional vs. Cladistic Classification: Traditional classification focuses on shared characteristics, cladistic classification emphasizes common ancestry and evolutionary relationships.
• Dinosaur Clades and Divergences: Dinosaurs split into Saurischia (lizard-hipped) and Ornithischia (bird-hipped). These clades contain various lineages and groups.
• Relationship Between Electron Wavelength and Allowed Orbitals in an Atom: Electrons' wave-like nature restricts them to specific orbital energies.
• Identifying the Major Clades of Dinosaurs: Saurischians include Theropods (like T. Rex) and Sauropodomorphs (like Brachiosaurus). Ornithischians include various herbivorous lineages.

Explore the fundamental concepts of scientific inquiry, including theories, hypotheses, facts, laws, and models. Understand the importance of falsifiability and the principles of uniformitarianism and catastrophism in scientific reasoning. Also, examine the concept of truth without certainty in science.