Human Evolution Exam 2

Homoplasy

A homoplasy is a character shared by a set of species but not present in their common ancestor. A good example is the evolution of the eye which has originated independently in many different species. Above Homoplasy is its technical definition used by biologists. A homoplasy has an older, pre-Darwinian meaning of similarity explained by a shared way of life. For example, the wings of insects, birds and bats are all needed for flying: they are homoplasious structures in the non-evolutionary, as well as the evolutionary, sense.

Monogamy

A male and female live in a pair bond for an extended period of time, perhaps years. Social monogamy is not reproductive monogamy (Ex. Gibbons may live as social monogamous pair but mate with other Gibbons) Female reproductive strategy: holds a territory and on each territory she has another male. Since males in monogomous pairs don't have to compete with other males, we don't see large canine / body (Ex. Gibbons except for hair color don't have sexual dimophism)

Biases in interpreting the fossil record

A number of dating techniques are useful in areas with volcanic sediments such as East Africa but can;'t be used in areas that are primarily made of sedimentary rocks such as Europe Anatomical Bias: animals w hard parts Demographic Bias: male vs. female

Outgroup

A taxon outside the group of interest. All the members of the group of interest are more closely related to each other than they are to the outgroup. Hence, the outgroup stems from the base of the tree. An outgroup can give you a sense of where on the bigger tree of life the main group of organisms falls. It is also useful when constructing evolutionary trees.

Plate Tectonics

A theory explaining the structure of the earth's crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates that move slowly over the underlying mantle.

Radio Carbon Dating (14C)

A way we use carbon to figure out how old an object is. If we found a piece of wood, we could found out how old it is. Carbon 14: Comes from Nitrogen. Nitrogen is hit with cosmic rays from space. Nitrogen is converted to Carbon: 6 Protons and 8 Neutrons. Atmosphere is made up of carbon dioxide (C12, occasionally C14) 1. Plants take the carbon through photosynthesis 2. I like to eat oatmeal squares, Carbon 14 ends up in the food, then in my body. 3. Carbon 14 in atmosphere = Carbon 14 in my body as long as I'm living. 4. When I'm not eating anymore, I don't have Carbon 14. 5. Measure the amount of carbon 14 (CHECK IF WE NEED TO KNOW EXACT). Limitation: at a certain point, the carbon 14 is so small (so old) that the measurement doesn't become accurate anymore. It works for the last 50,000 years.

Adapids

Adapidae is a family of extinct primates that primarily radiated during the Eocene epoch between about 55 and 34 million years ago Adapids were stem strepsirrhines. In particular, the anatomy of the adapid wrist and ankle show derived similarities with those of living strepsirrhines. However, adapids lacked many of the anatomical specializations characteristic of living strepsirrhines, such as a tooth comb. There are two major branches of adapids, subfamily Adapinae (adapines) and subfamily Caenopithecinae (caenopithecines). Caenopithecines are sometimes assigned to their own family, Caenopithecidae.[citation needed]

Arboreal vs. Terrestrial

Arboreal: Referring to animals that are adapted to life in the trees.(Ex. Strepsirhines include mostly arboreal species) Terrestrial: Referring to animals that spend most of their time on the ground rather than in the air, water, or trees. (Ex. Haplorhini Terrestrial).

• Multi-Male/Multi-female (Polygyny)

As the numbers in one group increase, it is harder to keep your females off other males. So he allows other males, but continues to have the majority. Priority goes to the alpha male.

Proconsul

Best known of the early dental apes which lived in Africa about 18-20 million years ago. Discovered in 1920s in Africa. Possessed long torso, quadrupedal, and no tail.

Fossil (trace, cast, true form)

Cast fossils (formed when a mold is filled in) Trace fossils = ichnofossils (fossilized nests, gastroliths, burrows, footprints, etc.) True form fossils (fossils of the actual animal or animal part).

Phylogenetics/Cladistics Approach

Cladistics: Cladistics attempts to classify organisms based on their evolutionary lineage. In a cladistic classification system, a single catagory, known as a clade, contains the most recent common ancestor of all organisms in the clade as well as all organisms decended from that ancestor. The organisms in a single clade may be morphological different, but they share an evolutionary relationship. Organsims that have developed similar morphological characteristics through converent evolution will generally be in different clades.

Law of Superposition

Definition: The older rock is normal found on the bottom. The farther down you go, the older it is going to be. Example: Locker... The farther you dig down, the older it gets.

Paleomagnetism

Definition: The study of earths magnetic record How do we learn about it: Using data gathered from Iron bearings in rocks. These rocks have recorded the orientation of earths magnetic field. When the rocks form, the magnetic orientation is locked in place and provides a record of Earths magnetic field. When a volcano erupts, basalt (lava / has high amount of iron bearing minerals), locks in the magnetic orientation.

Quadruped

Definition: an animal that has four feet, especially an ungulate mammal. Example: The majority of quadrupeds are vertebrate animals, including mammals such as cattle, dogs and cats, and reptiles, like lizards.

Biped

Definition: an animal that uses two legs for walking. Example: both the ostrich and the red kangaroo

• Ecological and Social hypotheses for brain evolution

Ecological: Suggests the ability to navigate and find food in complex environments led to brain expansion Primates have mental maps of their landscapes Frugivores have larger brains that closely related primate folivores Social: Suggests that large brain was selected for by increasingly complex social relationships Increases in group size elected for those individuals with brains better able to handle additional social input Tactical deception is more frequent i n high primates with bigger brains

Faunal Correlation

Faunal Cross-correlation is the use of animal bones found within an archaeological site to determine a relative date.

Homology/Homologous traits

Homology: traits inherited by two different organisms from a common ancestor. Example: all vertebrate animals (frogs, birds, fish, people) have skeletons because the ancestor of the vertebrates had a skeleton and passed that trait on to all of its descendants.

Hominoidea

Homonoidae ❖ Apes & Humans ❖ Apes are more similar to humans than any other animal - Broad noses - Broad palates - Larger brains - Long arms (except humans) - No tails - Short trunk

Arboreal Hypothesis

Hypothesis for the origin of primate adaptation that focuses on the value of grasping hands and stereoscopic vision for life in the trees.

Autapomorphy

In cladistics, an autapomorphy is a distinctive anatomical feature, known as a derived trait, that is unique to a given terminal group. That is, it is found only in one member of a clade, but not found in any others or outgroup taxa, not even those most closely related to the group. Example: Snakes have lost the two pairs of legs that characterize all of Tetrapoda, and the closest taxa to Ophidia - as well as their common ancestors - all have two pairs of legs. Therefore, the Ophidia taxon presents an autapomorphy with respect to its absence of legs.

Intra- vs Inter-Sexual Selection

Intra: Members of the same sex (of the same species) compete, fight or engage in combat with one another over the opportunity to mate with a female. Example: Because intrasexual selection often involves fighting, species or individuals well adapt for intrasexual selection will have developed better armourments (weapons) than their competition. Inter: Simply put, females choice. When the females chooses the best mate based on display or ornaments. Intersexual selection describes situations in which reproductive success is dependent on interplay between both sexes Example: Peacock's tail. Not usually beneficial to the male but the female prefers the larger ornaments as it signals the male's is able to cope with the hindrance.

R-selection vs. K selection

K Selected: exhibiting the opposite reproductive characteristics of r-selected animals. R Selected: Animals that reproduce more quickly, could colonize areas faster and rebound from population declines more quickly.

"Leakey's angels" (Fossey, Goodall, Galdikas

Leakey was so fascinated by Darwin's theory of evolution that he picked three women to study Gorilla, Orangutan and Chimpanzee. Jane Goodall: Witnessed a chimpanzee create a tool to catch fish. At the time, man was the only one who created tools - this changed everything. Dian Fossey: Had to work with Gorillas, gained trust by acting like them (imitating the voice). Made a lot of contact with gorillas but got killed in her cage. Birute Galdikas: Worked with red great ape for over 30 years at "Camp Leakey" which she helped preserve, an area to save Orungatan

Quadrumanus

Locomotion form involving movement of only one appendage at a time. Using hands and feet much as we use hands.

Brachiation/Suspensory

Moving through trees with arm: Some New World monkeys such as spider monkeys and muriquis are semibrachiators and move through the trees with a combination of leaping and brachiation. Some New World species also practice suspensory behaviors by using their prehensile tail, which acts as a fifth grasping hand.

Sivapithecus (ASK)

Named after Hindu Figure Siva, found in late Miocene sediments of the Himalayan foothills of northern India. Similar: Cranial and Dental remains of Sivapithecus exhibit several similarities with Orungatan. Eye orbits are long and narrow Different: postcrnial remains indicate arboreal quadrupedalism rather than quadrumanous.

Prehensile tail

New World Monkeys have a "fifth limb" - a tail capable of grasping and holding onto items Old World Monkeys have tails but none are prehensile

Diurnal vs. Nocturnal vs. Crepuscular

Nocturnal: Active at night Diurnal: Active during day Crepuscular: appearing in twilight

Omomyids

Omomyidae is a family of early primates that radiated during the Eocene epoch between about 55 to 34 million years ago (mya). Found in North America, Europe, Asia, and possibly Africa, making it one of two groups of Eocene primates with a geographic distribution spanning holarctic continents Omomyids probably gave rise to haplorhines (Mostly the New World)

• One Male/multi-female (Polygyny)

One male lives with as many females as he can monopolize. For example: Baboon females bond to one another and the male. Gorillas, half of all groups are one male Males who aren't able to obtain females usually live alone or attack the males who have females. Ring-Tailed Lemurs / Sifakas: The resident male finds it impossible to restrict access to the groups females and the female mate with the extra group males.

Phenetic Approach

Phenetics attempts to classify organisms based on overal similarity, typically in morphology, without regard for their evolutionary relationships. Basically, it's classification based on how similar to the organisms look. A single catagory in a phenetic classification system may contain organisms that have different evolutionary histories but have developed similar morphological features through converent evolution.

Phylogeny/Cladogram

Phylogeny: The history of the evolution of a species or group, especially in reference to lines of descent and relationships among broad groups of organisms. Cladogram: A diagram used in cladistics which shows relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants or how much they have changed.

Platyrrhines vs Catarrhines

Platyrrhini: Platyrrhini means rounded- nose Four more premolar teeth than Old World monkeys Completely arboreal Partial color vision Catarrhines: More biochemically and physically similar to humans than New World Monkeys Occupy a wide range of environments Large range of social structures

Uranium 238 dating

Radiometric techiqniues using the decay of uranium to estimate an age for calcium carbonates including flowstone, shells, and teeth

Dominance rank

Ranking of individual primates in a group that reflects their ability to displace, intimidate or defeat group mates in contests. Usually happens in multi male pollingy

Biostratigraphy

Relative dating technique using comparison of ofsossils from different stratigraphic sequences to estimate which layers are older and which are younger.

Sexual Dimorphism

Sexual dimorphism is the physical difference observed between males and females of the same species. In primates, sexual dimorphism is often most notable in differences between male and female body size and canine size

Stratigraphy

Stratigraphy is a branch of geology which studies rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy includes two related subfields: lithologic stratigraphy or lithostratigraphy, and biologic stratigraphy or biostratigraphy

Strepsirhine vs Haplorhine

Strepsirhine: Have more more primitive traits than other primates Often lack one or more of the general characteristics of primates - like color vision Rely more heavily on the sense of smell Smaller brains (relative to body size) Grooming claw Post-orbital bar Haplorhine: No tooth gap Post-orbital closure Larger Brain

Symplesiomorphy

Symplesiomorphy is similarly a shared primitive trait

Synapomorphy

Synapomorphy is a derived trait shared by two or more groups

Taphonomy

Taphonomy is the study of what happens to an organism after its death and until its discovery as a fossil. This includes decomposition, post-mortem transport, burial, compaction, and other chemical, biologic, or physical activity which affects the remains of the organism. Helps us figure out what happened to skeleton after the organism died. Can only been done if a site hasn't been disturbed.

Aegyptopithecus (ASK)

The Fayum in Egypt is famous for early anthropoids, such as Aegyptopithecus who may be ancestral to Old World Monkeys and apes and other of which be ancestral to all monkeys

Adaptive Radiation

The fast evolution of many species from a common ancestor. They call it radiation because different species radiate out of a common ancestor. Example: When an animal moves into a new area that has a lot of ecological opportunities. When darwin saw the variety of finches, he observed that each finch was adapted to his highland.

Intermembral Index (IMI)

The intermembral index is a ratio used to compare limb proportions, expressed as a percentage. It is equal to the length of forelimbs (humerus plus radius) divided by the length of the hind limbs (femur plus tibia) multiplied by 100.

Visual Predation hypothesis

The proposition that unique primate traits arose as adaptations to preying on insects and on small animals.

Half-life

The time it takes for half of the original amount of an unstable isotope of an element to decay into more stable forms. Potassium: 1.25B - Date oldest rock on earth Uranium: 4.4B

Thermoluminescence

This dating technique depends on radiation. Low level of electro radiation given by elements such as Uranium and Thorium and Potassium. In this technique electrons can only be released through fire. So archeologist take pots of clay, heat it, and then they can measure the energy/ light emitted and give an estimate when the pot was last heat. This technique can be used for pottery and tools. It has reliable range double of carbon dating. Limitations: Radiations permeate objects. An object found underwater will expose the electrons far more slowly than on dry land. 100-500,000 Years depending on material.

Infanticide

This often happens in high density population. This suggested that infant killing was an adaptive strategy evolved through sexual selection to promote a males genes at the expense of other males. (Often happens with Langurs).

Electron-Spin Resonance

Tooth enamel. Tooth is powdered and exposed to microwaves. The trapped electrons resonate as they absorb the microwaves. We must model the way uranium is introduced into the booth in the first place. Adjust age because the mineral of tooth enamel, accumulates all of its radioactivity after burial. Typically to 500,000 years and possibly a few million years

Oxygen Isotope Ratios

Two oxygen isotopes (o^18) in atmosphere and ocean water changes temperature. Larger ratio in snow that forms warm air AND smaller in snow that forms in cooler air

Biped

Two-footed animal

Potassium/Argon (K/Ar or (40Ar/39Ar)

WE estimate the age since eh time of the eruption by considering how much argon has accumulated. As molten lava solidifies, AR will be trapped inside. We measure Ar and the remaining K to calculate half life. TH longer the time since the lava cooler, the greater amount of Ar and less K present. 4.5B Years. The method dates the timing of the formation of the volcanic rock.

Polyandry

When females compete over access to males, the opposite pattern emerges and females are often slightly larger in size than males. Polyandry is thought to occur because the high frequency of twinning and the relatively high weights of infants in these species make the rearing of infants unusually difficult Example: tamarins, marmosets

Sexual Signals

o Sexual Receptivity Signals: o Sexual Signa;s to promote their reproductive success. These signal can be behavioral, physiological and anatomical o Those signals advertise a females willingness to mate / sexual receptivity. o Female Langurs arch their tails over their back sand shake their heads side to side. o The time around ovulation often produces changes in female appearance and behavior o Although it was long though that such female features existed for the convenience of males, we now release that females evolved these traits to aid their own strategy - using sexual signals to choose their males. o Baboons and Chimpanzees possess swellings during a brief portion of monthly cycle.