Large Exam 1 Flashcards
What is the definition of evolution?
A change in allele frequencies over time.
How do the forces of evolution change allele frequencies?
Through Time, Mutations, and Natural selection.
How much time is needed to see evolutionary change?
Not very long or very long.
What are the conditions necessary for natural selection to occur?
There must be polymorphism in a trait, it must then be heritable, and the resulting variation must lead to difference in survival and reproductive success.
What are some examples of natural selection in action presented in class?
Rock pocket mice, Finch beak size, trichromacy in capuchin monkeys.
What is speciation?
The process by which species diverge.
What is the Biological Species Concept?
Species are individuals that can breed and produce viable offspring who can also produce viable kids.
What is the Evolutionary Species Concept?
Species are a lineage of organisms with a distinct evolutionary trajectory.
What is the Ecological Species Concept?
Species are a groups of organisms that share a common ecological niche.
What is anagenesis?
A population changes as a whole.
What is cladogenesis?
A population splits into two or more populations.
What is directional selection?
Selection that favors one extreme.
What is balancing/stabilizing selection?
Selection that favors a median, heterozygous trait.
What is disruptive/diversifying selection?
Selection that favors both extreme ends of a trait.
What are reproductive isolating mechanisms?
Mechanisms by which populations and communities become separated from each other with no gene flow.
What is allopatric speciation?
Speciation occurs when a population is separated by a physical, often geographical boundary.
What is peripatric speciation?
Speciation occurs when a small group of individuals breaks off from the original community.
What is parapatric speciation?
Speciation occurs without a solid boundary and populations can still intermix.
What is sympatric speciation?
Speciation occurs within the former population.
What is a cladogram?
Graphical representation of the branching sequence of evolution based on shared derived traits and common ancestry.
What is a primitive trait?
Inherited trait from a common ancestor that is still retained and has not really changed.
What is a derived trait?
Traits that occurred via mutation in a most recent ancestor of a branch.
What are homologous traits?
Traits that are shared among organisms due to a shared common ancestor.
What are analogous traits?
Traits that are shared among organisms due to a shared niche.
What is taxonomy?
Science of classifying and organizing organisms in a nested hierarchy.
What is a taxon/taxa?
Group of organisms of any rank.
What is a holotype?
The example organism that is used to describe and represent its species.
What is apomorphy?
Unique/derived, non-primitive traits, unique to a lineage.
What is synapomorphy?
Shared derived traits.
What is plesiomorphy?
Primitive, retained traits.
What is symplesiomorphy?
Shared primitive traits.
What is phylogeny?
Evolutionary history and relationship among individuals or groups of species.
What is phenetics?
Grouping based on overall similarities.
What is paraphyly?
Branches of organisms grouped together on a cladogram based on perceived similarities in traits and behaviors.
What is polyphyly?
Branches of organisms grouped together on a cladogram based on a shared recent common ancestor minus one or more.
What is monophyly?
Branches of organisms that are grouped together based on their shared most recent common ancestor.
What is parsimony?
The least amount of changes needed to explain the acquisition of a trait.
What is the last common ancestor?
The most recent common ancestor between clades of organisms from which their shared derived traits arise.
What are factors that lead to speciation?
Restriction of gene flow in some way, time, heritable mutations.
How are species defined?
Biological Species Explanation: Organisms that can produce viable offspring who can also produce viable offspring.
What are the conventions of taxonomy?
Everything must be classified into nested hierarchies with a binomial scientific name and a common name.
What is included in the binomial (scientific name)?
The genera and species.
What does one look for to construct a cladogram?
Shared traits and behaviors, genetics.
What are plesiomorphy, symplesiomorphy, apomorphy, and synapomorphy?
Plesiomorphy: Primitive traits. Symplesiomorphy: Shared Primitive traits. Apomorphy: Unique/derived traits that are not primitive. Synapomorphy: Shared derived traits.
How does looking at certain traits affect a cladogram?
Helps establish groups of organisms based on their features and evolutionary trajectory and pinpointing a common ancestor.
What are mammals?
Organisms that produce milk, live young, have fur, and are warm-blooded.
What is the post-orbital bar?
Bone which connects the frontal to the zygomatic bone.
What is post-orbital closure?
A space posterior to the postorbital bar that blouses off openings to the orbit.
What is stereoscopic vision?
Ability to see things in 3-D.
What is visual acuity?
Sharpness and clarity of vision.
What is generalized dentition?
Overall arrangement and formula of the teeth.
What is life history?
The way an organism organizes growth and reproduction in a way that optimizes survival and reproduction.
What is an anthropoid?
All living and extinct monkeys, apes, and humans.
What is a haplorhine?
Dry-nosed primates which include tarsiers and simians.
What is a catarrhine?
Old-World monkeys, gibbons, and great apes.
What are cercopithecoids?
Catarrhine group including old world monkeys.
What are hominoids?
Includes all great apes.
What is a Y-5 molar?
The distinct molar crown pattern of great apes and humans with a 5th crest.
What are features unique to all mammals?
Warm blooded, live young, milk producing, furry, four chambered hearts, three middle ear bones.
What features are unique to ALL primates?
Larger brain, slow life-histories, less young, longer life-span, grasping hands, acute vision.
What features are unique to catarrhines?
From the old world, tubular ectotympanic bone, no prehensile tail, 2,1,2,3 dental formula.
What are cercopithecoids and hominoids?
Both are catarrhines. Cercopithecoids are old world monkeys. Hominoids are the great apes.
What features are unique to hominoids?
No tails, broader and shorter torso, flexible shoulder joint, larger brain.
At which taxonomic level are primates differentiated?
Order.
What is paleontology?
The study of fossils.
What is a fossil?
The mineralized remains of organisms that died.
What is an endocast?
A mineralized cast of the internal brain structure.
What is taphonomy?
The study of how things ended up in the archaeological records.
What is stratigraphy?
The study of rock layers and the events they represent.
What are the principles of stratigraphy?
Original Horizontally, Superposition, Cross-Cutting Relationship, Faunal Succession.
What is permineralization?
The process by which a fossil forms: through minerals replacing organic matter.
What is a trace fossil?
Fossilized evidence of behavior like footprints.
What is radiometric dating?
Dating via measuring the decay rate through half-lives of radioactive elements.
What is absolute dating?
Dating via measuring physical properties of the artifact or organism itself.
What is relative dating?
Dating through association with related items of a known date.
What is calibrating dating?
Dating via counting back an expected number of changes in time.
What is paleomagnetism?
Dating via changes in the earth’s magnetic field.
What is a molecular clock?
An expected number of mutations that occurs between lineages.
What is continental drift?
The breaking and movement of continents from Pangea to what they are today.
What is the Oligocene?
Epoch just prior to the Miocene, cool, and contains the earliest known cercopithecoids and hominoids.
What are Y-5 molars?
A distinct trait of hominoids indicating a Y-shaped cusp on the molars.
What is hypoconulid?
The fifth cusp from a Y-5 molar pattern unique to hominoids.
What are Proconsulids?
Earliest stem hominoid from the early to mid Miocene.
What is the Miocene?
Epoch after the Oligocene with many apes.
What is Ekembo/Proconsul?
A species of Proconsulids that is ape-like and monkey-like.
What is Morotopithecus?
20.6 mya, Uganda, earliest evidence of upright posture.
What is Pierolapithecus?
Mid Miocene species known for long fingers and toes.
What are the characteristics of the earliest hominins?
Ape-like in having no tail trochlear ridge and a flexible ankle; monkey-like in having inflexible wrists, fingers, and toes, a pronograde trunk, and pelvis.
What is Morotopithecus?
A hominin from Uganda dating back to 20.6 mya, known for the earliest evidence of upright posture and orthograde features like vertebra and glenoid fossa.
What are the key features of Pierolapithecus?
A mid Miocene hominin from Spain (13-12.5 mya) with long fingers and toes, flat nasal bones, deep palate, ape-like ribs and vertebrates, and orthograde vertical climbing without suspensory motion.
What is Dryopithecus?
A mid-late Miocene hominin from Spain (11-9.5 mya) with an African ape-like cranium resembling a gorilla and a postcranial skeleton like an orangutan, featuring large hands with suspensory features.
What is Ouranopithecus?
A late Miocene hominin from Greece (10-9 mya) possibly linked to the African ape and human clade.
What are the characteristics of Oreopithecus?
An 8 mya hominin from Italy with 6 cusps on molars, a suspensory, short and broad trunk, and a flexible elbow, possibly a flexible hip.
What is Chororapithecus?
A hominin from Kenya dating back to 10 mya.
What is Kapi?
A hominin from India (13.8-12.5 mya) considered a gibbon ancestor and a stem hylobatid.
What is Yuanmoupithecus?
A late Miocene hominin from China (8.2-7.1 mya) recognized as a gibbon ancestor with very similar teeth.
What is Bunopithecus?
A hominin from China (2.6 mya - 774 kya) with teeth similar to hylobatids.
What is Khoratpithecus?
A hominin from Thailand (9-7 mya) similar to orangutans, characterized by wrinkled enamel and a robust mandibular body.
What is Sivapithecus?
A hominin from India/Pakistan (12-8 mya) with a skull similar to orangutans but a body that was not ape-like and was pronograde.
What is Gigantopithecus?
A hominin from South and Southeast Asia (2.6 mya - 800 kya) part of the orangutan lineage, known only from mandible and dental remains, very large, and went extinct due to specialization or competition with H. erectus and H. sapiens.
What was the climate like during the early, middle, and late Miocene?
The early Miocene was warm and humid, the middle Miocene began to cool down with dropping sea levels, and the late Miocene continued to cool and dry as subtropical forests turned more deciduous.
Where are the major hominin fossils found and from what time period?
Major hominin fossils are found in Central and Northern Africa, Europe, and Asia, roughly from the Miocene to Pleistocene.
How did climate affect resources and ape evolution?
The climate was warm in the early Miocene, cooling towards the end, leading to higher sea levels dropping, allowing apes to migrate into Europe and Asia, and later retreating back into Africa as forests changed.
What is one biogeographic hypothesis explaining ape migration?
The text does not provide a specific biogeographic hypothesis.
Why is it difficult to differentiate ape fossils in the early Miocene?
There is often very little fossil evidence remaining, typically just teeth or indistinguishable bones, making anatomy and behavior hard to decipher.
Is there evidence of different stages in ape locomotion evolution?
Yes, evidence includes the angle of spinous processes, transverse processes, forearm and hindleg lengths, and scapula orientation, indicating suspensory locomotion.
