Dino Planet

Exam Flashcards

Mesozoic Era

• Divided into three periods:

• Triassic: Start at 252 million years ago

• Jurassic: Starts at 201 million years ago

• Cretaceous: Starts at 145 million years ago; ends with the mass extinction at 65.5 million years ago

What is a Mineral?

A naturally occurring inorganic substance with a defined chemical composition and crystalline structure. Minerals are the building blocks of rocks and can form through geological processes.

Name some common minerals

Some common minerals include quartz, feldspar, mica, calcite, and pyrite.

What is a rock

A rock is a consolidated aggregate of minerals forming a significant part of the Earth's surface. Rocks can be classified into three main types: igneous, sedimentary, and metamorphic.

How can rocks be distinguished

by their mineral composition, texture, and formation process. Rocks can be distinguished

Igneous Rocks

are formed from the solidification of molten magma or lava.

Sedimentary Rock

is formed from the accumulation and compaction of mineral and organic particles over time, often in layers.

Types of sedimentary rocks

Shale/Mudstone (from clay low energy environment), Sandstone (from sand, medium energy environment), Conglomerate (high energy environment)

Metamorphic Rock

is formed from the alteration of existing rocks through heat, pressure, or chemically active fluids.

Fossilization Process

is the series of processes through which organic remains are preserved in sedimentary rock, often involving burial, compression, and mineral replacement.

Fossil-Preserving Environments

are specific settings, such as sediments in river deltas or ocean floors, where conditions favor the preservation of organic remains, often due to low oxygen levels and rapid burial.

Layers of the earth

are distinct strata that make up the Earth's structure, including the crust, mantle, core.

Physical Properties of the Earth

Lithosphere (rigid outer layer), Asthenosphere (ductile layer beneath lithosphere)

Types of Plate boundaries

are locations where two tectonic plates interact, including divergent (move apart), convergent(come together), and transform (slide past each other) boundaries, each exhibiting unique geological features and activities.

Plate tectonics During the Mesozoic

Early: All continents together (low sea level), Late: Continents (high sea level)

Types of Fossils

Body fossils: Direct evidence like bones and tissues

Trace fossils: Indirect evidence like tracks and feces

Permineralization

When organic material decays and pores get replaced by minerals (eg quartz)

Types of dinosaur fossils

bones and skeletons, eggs, gastroliths, coprolites, skin impressions

How long did dinosaurs exist

Over 170 million years

Taxonomy

The science of classifying and naming living organisms, including dinosaurs, based on shared characteristics and evolutionary history. It involves hierarchical categories such as kingdom, phylum, class, order, family, genus, and species.

Systematics

The branch of biology that deals with the classification of organisms and their evolutionary relationships, often utilizing genetic data to understand lineage patterns.

Natural Selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring, driving evolution.

Homologous Traits

Features in different species that share a common ancestry but may serve different functions, indicating evolutionary relationships.

Analogous Traits

Features in different species that serve similar functions but do not share a common ancestry, often resulting from convergent evolution.

Cladistics

A method of classifying species based on shared derived characteristics and their evolutionary relationships, often represented in a branching diagram called a cladogram.

Parsimony

The principle of selecting the simplest scientific explanation that fits the evidence, used in cladistics to minimize assumptions when constructing evolutionary trees.

Clades

Groups of organisms that include an ancestor and all its descendants, reflecting a branch of the evolutionary tree.

Atomic Weight

The average mass of an element's atoms, measured in atomic mass units, reflecting the number of protons and neutrons in the nucleus.

Isotopes

Variants of the same element, differing in neutron count

Half-life

is the time required for half of a sample of a radioactive substance to decay into another element or isotope.

Types of rock that can be dated

include igneous, sedimentary, and metamorphic.

Lithostratigraphy

Interpreting the age of the earth’s layers

Principle of superposition

states that in any undisturbed sequence of rocks, the oldest layers are at the bottom and the youngest are at the top.

Principle of Cross cutting relationships

is a geological principle that states that a rock or feature that cuts across another is younger than the rock or feature it cuts.

Principle of inclusion

is a geological principle stating that if a rock body contains inclusions of another rock, the inclusions must be older than the rock containing them.

Biostratigraphy

Use of fossil types in rocks to determine ages and correlate rock sequences over wide areas

Global climate changes influenced by

sea level, greenhouse gasses, volcanic activity, continental configurations

Gymnosperms

a group of seed-producing plants that includes conifers, Ginkgo, and cycads, characterized by seeds that are not enclosed in an ovary.

Angiosperms

Pangea

Chordates

a phylum of animals that includes all vertebrates and some invertebrates, characterized by having a notochord at some stage of development.

Tetrapods

Four-legged vertebrates including amphibians, mammals and their common ancestors

When did first amphibians appear

360 million years ago

Amniotes

a group of tetrapods that lay eggs on land or retain them within the mother, including reptiles, birds, and mammals.

classification of amniotes

Anapsids (no opening, synapsids (one temporal fenestra), and diapsids (two temporal fenestrae).

Archosaurs

Evolved in the Triassic with innovations like socketed teeth and antorbital fenestrae. They include dinosaurs and crocodiles.

Dinosaur characteristics

• Larger jaw muscle attachments for powerful biting.

• Stronger forelimbs and unique mesotarsal joint facilitating upright movement (perforate acetabulum).Dinosaur characteristics include larger jaw muscle attachments for powerful biting, stronger forelimbs with a unique mesotarsal joint that facilitates upright movement, and a perforate acetabulum.

Saurischians

A group of dinosaurs characterized by a lizard-like pelvic structure, which includes theropods and sauropodomorphs.

Ornithischians

A diverse group of dinosaurs characterized by a bird-like pelvic structure, which includes armored dinosaurs, stegosaurs, and hadrosaurs.

Major groups of dinosauria

Saurischians (includes theropoda) and Ornithischians, the two primary clades of dinosaurs, distinguished by their pelvic structures.

What is a Theropod

A subgroup of Saurischians (not sauropods) that were primarily bipedal carnivorous dinosaurs, with claws and serrated teeth including species like Tyrannosaurus rex and Velociraptor.

Theropod walking

Narrow legs with one foot placed in front of the other. Horizontal orientation balancing head and tail over the pelvis.

Theropod arm structure

Typically short and strongly built, with three digits ending in claws, allowing for grasping and hunting.

Theropod jaws

Characterized by a narrow structure with sharp, serrated teeth designed for slicing flesh (scissor like). This adaptation helps in efficiently capturing and consuming prey.

Theropod teeth

Usually sharp and serrated, optimized for cutting flesh and aiding in predation.

Theropod vision

Often characterized by excellent depth perception and acute vision, allowing for effective hunting and navigation in various environments. forward facing eyes

Theropod brains

Generally large and complex, facilitating advanced behaviors such as problem-solving and social interaction among these carnivorous dinosaurs.

Theropod sexual dimorphism

Refers to the physical differences between male and female theropods, which may include variations in size, coloration, or ornamentation, often linked to mating behavior.

Theropod feathers

• Evolved for multiple reasons, including display, insulation, and flight.

• Types of feathers include:

• Monofilamentous (hair-like), downy (loose), contour (hooked barbs), and flight feathers (asymmetrical).

Uses for feathers

Feathers in theropods served several purposes, including display for attracting mates, insulation for temperature regulation, and aiding in flight.

Theories of flight origin

• Three Hypotheses for the Origin of Flight:

  1. Tree down: Climbing and gliding.

  2. Ground-up: Running and leaping.

  3. Compromise: Combination of avenues, assisting in running up surfaces

Theropod diversification

• Rapid diversification observed during Late Triassic:

  • Ornithischia split from Saurischia.

  • Sauropods diverged from Theropods within this period.

Herrerasaurus

early theropod genus >230 Ma.

Walked on four hind toes (later theropods reduced to three main digits, with digit 1 diminished).

Neotheropods

a group of theropod dinosaurs that show evolutionary advancements such as the loss of the fifth toe and the development of the furcula, characteristics that are key in the lineage leading to modern birds.

Coelophysis

an early theropod dinosaur known for its slim build and long limbs, reaching up to 3 meters in length, and lived during the Late Triassic period.

Tetanurae

a clade of theropod dinosaurs characterized by features such as a rigid tail, advanced dental adaptations, and the presence of a furcula, including well-known groups like carnosaurs and coelurosaurs.

Spinosaurus

• Approximately 15 m long; notable features include:

  • Long snout with nostrils placed mid-snout, not at the front.

  • Long, powerful arms and dense (non-hollow) bones.

  • Adaptations suggest a semi-aquatic life.

Avetheropoda

a clade of theropod dinosaurs that includes modern birds and their closest extinct relatives, characterized by features such as a lightweight structure and advanced respiratory systems. Developed pneumatic bones aiding in countering size and weight for flight.

Carnosauria

a group of large theropod dinosaurs that includes species such as Allosaurus and Tyrannosaurus. They are characterized by their massive size, formidable teeth, and predatory adaptations.

Coelurosaurs

• Highly diverse including both larger and smaller species (e.g., Tyrannosaurus and other small theropods).

• Notable for possessing relatively large brains, indicating advanced behavioral capabilities.

Ornithomimids

• Bird-like theropods often referred to as ostrich-like (speedy runners), with traits including:

  • Long legs, small skulls, large eyes.

  • No teeth, primarily herbivorous, had the ability to run at speeds up to ~50 km/hr.

Deinocheirus

• Initially known only from fossilized arms; 2014 discoveries revealed:

  • Long claws and a presumed semi-aquatic piscivore/herbivore nature with evidence of stomach gastroliths

Maniraptors

• Recognized by modified wrist bones allowing more movement.

• Group includes Oviraptors, notable for their behavior related to egg-stealing, as evidenced by fossil finds.

Paraves

• Longer arms and wings with layered feathers.

• Backward pelvis configuration, akin to modern birds

Dromaeosaurids

A family of feathered theropod dinosaurs characterized by their large claws, agile bodies, and often predatory behavior. They include notable genera such as Velociraptor.

Troodontids

Known for their extensive feather coverage; specimens suggest colorful plumage based on melanosome studies

Avialae

• Represents the transition to modern birds, characterized by full flight capabilities and loss of teeth.

• Evidence points to feathers being a key characteristic, predating full avialae classification

Archaeopteryx

A transitional fossil between non-avian dinosaurs and modern birds, featuring feathers and the skeleton of a theropod. Often considered the first bird, it lived during the late Jurassic period.

Melanosomes

Cellular structures that contain melanin, influencing coloration in feathers and skin.

Sauropods

Large, quadrupedal, long-necked, small head dinosaurs known for their herbivorous diet and massive size, living during the Mesozoic era.

Prosauropods

Early, long-necked dinosaurs that are ancestors to true sauropods, generally smaller in size and herbivorous. They lived during the Late Triassic to Early Jurassic periods.

Sauropod characteristics

• Size and Diversity:

  • Became very large and diverse during the Jurassic and continued into the Cretaceous.

  • Notably included the largest dinosaurs known.

• Distinct features:

  • Over 40 defining characters mainly related to their shape and behavior.

  • Quadrupedal, herbivorous, small-headed, long-tailed, and long-necked creatures that thrived for ~140 million years.

Sauropod teeth

• Developed skinny, pencil-like teeth; in derived versions (Diplodicoids), teeth are primarily at the front.

Sauropod Skulls

• Small skulls relative to body size, accounting for less than 5% of body length.

• Evolved nostrils that moved upwards in more derived forms.

Sauropod necks

Long and flexible structures that allowed for high browsing and foraging, critical for their herbivorous diet.

Neck vertebrae contained pneumatic holes and air pockets for weight distribution.

• Most sauropods maintained a horizontal neck position, balanced by their tail, supported by strong interlocking vertebrae.

Sauropod legs

• Legs were denser than neck bones to support weight.

• Foot structure included:

  • Front foot standing on toes (digitigrade) with one large claw.

  • Back foot with flat toes.

  • Trackways indicated narrow stances with no tail marks.

Sauropod Behavior and Reproduction

Sauropods exhibited various behaviors including social interactions and nesting strategies. Many species likely engaged in herding and laid eggs in communal nesting sites, suggesting a degree of parental care.

Two main branches of sauropods:

• • Diplodicoids: Long, lightweight bodies with long skulls and teeth positioned at the front (e.g., Diplodocus, Apatosaurus).

  • Macronaria: Shorter, heavier bodies with smaller skulls and powerful bites (e.g., Brachiosaurus, Titanosaurs).

Ornithischians

• Thyreophorans are one of the two major clades of Ornithischians, characterized by defensive adaptations including armor and spikes.

• Example: Stegosaurus juxtaposed with the predatory Allosaurus shows the contrasting adaptations for survival in different environments

Thyreophorans

A clade of Ornithischian dinosaurs known for their armor and defensive features, including plates and spikes, which were used for protection against predators.

Ornithischian Pubis Orientation

• The pubis is rotated backward, positioned closely and parallel to the ischium. This adaptation may have allowed for a more barrel-shaped gut, facilitating the digestion of fibrous gymnosperms.

Ornithischian Predentary Bone

All ornithischians possessed a predentary bone, a scoop-like structure at the front of the lower jaw, aiding in vegetation management.

Ornithischian Jaw Structure and Chewing Adaptations

Ornithischians had a unique jaw structure with specialized teeth and a powerful chewing mechanism, allowing them to efficiently process tough plant materials.

Two main subgroups of Thyreophorans:

Stegosaurs (spikes and plates) and Ankylosaurs ( heavy armor and tail clubs)

Active Defences

Offense strategy, such as using the tail (e.g., Ankylosaurs' tail club).

Passive Defenses

Structural adaptations (e.g., armor plates, spikes) to deter predators.

Scutes

Small bony plates or scales found on the skin of certain reptiles, including some dinosaurs like Ankylosaurs, which provide protection. In stegosaurids, scutes varied in shapes and sizes, suggesting differentiation between species and potential sexual dimorphism

Marginocephalians

A clade of dinosaurs characterized by their distinctive bony frills and thick skulls, including families like ceratopsians and pachycephalosaurs, known for their varied defensive structures.

Pachycephalosauria

A group of bipedal dinosaurs (thick headed reptiles) known for their thick, domed skulls, which were likely used in head-butting behavior and display. They include both small and large species, exhibiting various forms of head ornamentation.

Pachy Neck

High muscles in neck and brain orientation away from impact help in "head-banging" behaviors.