ANTH 122 Midterm

Mutation

- A change in a gene or chromosome - Results in a variant form of a gene that may be transmitted to subsequent generations - Mutations are essential for evolution to occur because they increase genetic variation and the potential for individuals to differ - As mutations occur, natural selection decides which mutations will live on and which ones will die out - If the mutation is beneficial, the mutated organism survives to reproduce, and the mutation gets passed on to its offspring

Jean Baptiste Lamarck

- A french natural historian who was an early proponent of the idea that evolution occurred and proceeded in accordance with natural laws - His major idea was the inheritance of acquired characteristics - According to Lamarck, organisms altered their behavior in response to environmental change - Their changed behavior, in turn, modified their organs, and their offspring inherited those "improved" structures - Ex: giraffes developed their elongated necks and front legs by generations of browsing on high tree leaves - the exercise of stretching up to the leaves altered the neck and legs, and their offspring inherited these acquired characteristics - Lamarck held that evolution was a constant process of striving toward greater complexity and perfection - Lamarck is credited with helping put evolution on the map and with acknowledging that the environment plays a role in shaping the species that live in it

Australopithecus africanus

- A gracile australopithecine from South Africa - It was the first fossil of a human ancestor ever found in Africa and was also the first to be classified in the genus Australopithecus - A. africanus was of slender build, or gracile, and was thought to have been a direct ancestor of modern humans - Has a more human-like cranium permitting a larger brain and more humanoid facial features - The child that was found was Taung

Species

- A group of similar organisms that can breed and produce fertile offspring - Species are made up of organisms that are evolving together - No species exists in a vacuum; every form of life on Earth interacts over time with other organisms, as well as with its physical environment - For that reason, the evolution of one species influences the evolution of species with which it coexists by changing the natural selection pressures those species face

The Great Chain of Being

- A hierarchical structure of all matter and life, thought in medieval Christianity to have been decreed by God - The chain starts with God and progresses downward to angels, humans, animals, plants, and minerals - Its major premise was that every existing thing in the universe had its "place" in a divinely planned hierarchical order, which was pictured as a chain vertically extended

Radiometric dating

- A method of dating geological or archeological specimens by determining the relative proportions of particular radioactive isotopes present in a sample - In East Africa, many early hominin sites are associated with the Rift Valley - Here, the presence of volcanic activity has permitted the use of radiometric dating techniques - Volcanic eruptions were very common in the developing Rift Valley, resulting in the accumulation of sometimes enormous amounts of volcanic ashes - This volcanic material can be dated to find very accurate time frames to find the dates of bones or fossils

Hominid

- A primate of a family that includes humans and their fossil ancestors and at least some of the great apes - Human evolution is the evolutionary process that led to the emergence of anatomically modern humans, beginning with the evolutionary history of primates and leading to the emergence of Homo sapiens as a distinct species of the hominid family, the great apes

Neo-Darwinism/Modern synthesis

- A revision of Darwin's original theory of evolution to include modern genetics - The Modern Synthesis describes the fusion of Mendelian genetics with Darwinian evolution that resulted in a unified theory of evolution - Modern synthesis is important because it is the union of ideas from various fields of biology - It emphasized the genetic basis of evolution - Mechanisms of evolution other than natural selection are recognized as playing important roles

Bone marrow

- A soft tissue inside the bone that produces blood cells - Archaeological evidence suggests that early hominins participated in a variety of tool-related activities, such as smashing bone to access marrow - Ancestors of modern humans may have scavenged calorie-rich bone marrow from already dead animals - Over the course of some 6 million years, the size of the human brain has increased by over 300 percent - this evolution required a rich reservoir of energy - Bone marrow is an excellent source of surplus energy

Gene

- A unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring - Evolution is the process by which populations of organisms change over generations - Genetic variations underlie these changes - Genetic variations can arise from gene mutations or from genetic recombination - If a trait is advantageous and helps the individual survive and reproduce, the genetic variation is more likely to be passed to the next generation (natural selection) - Over time, as generations of individuals with the trait continue to reproduce, the advantageous trait becomes increasingly common in a population, making the population different than an ancestral one

What are robust australopithecines? (species and dates)

- Aethiopicus 2.7-2.5 myr - Boisei 2.3-1.2 myr - Robustus 1.2 myr

Using finches and their environments and modern dog-breeders, what specifically did Darwin analyze in order to theorize "Descent with Modification?

- After 5 weeks in the Galapagos, Darwin took home a bunch of finches from the islands - He realized that the different types are from different islands which made him realize that species change - Darwin realized that just like we breed dogs to get certain traits (such as mixing a fast dog with a hunting dog to get a fast hunting dog) this is happening naturally in nature to get certain traits to prevail - The creatures that survived were those best adapted to the specific environments they lived in - Ex: The finches beaks transformed to fit the diets

Australopithecus afarensis

- An early australopithecine from East Africa that had a brain size equivalent to a modern chimpanzee's and is thought to be a direct human ancestor - Most well known one, named Lucy - Dated between 3.7 -2.9 myr - The back chewing teeth of A.afarensis are very large, but the canines are human-like - A.afarensis had a brain size like those of chimpanzees, and there was probably significant body size differences between males and females - Upon her discovery, Lucy became the oldest potential ancestor for every known hominin species - One of the best known of our ancestors due to a number of major discoveries including a set of fossil footprints and a fairly complete fossil skeleton of a female nicknamed 'Lucy'

Neanderthal

- An extinct species of human that was widely distributed in ice-age Europe - Fossil evidence suggests that a Neanderthal ancestor may have traveled out of Africa into Europe and Asia - There, the Neanderthal ancestor evolved into Homo neanderthalensis some 400,000 to 500,000 years ago - The human ancestor remained in Africa, evolving into our own species—Homo sapiens

Homologous body structures

- An organ or body part that appears in different animals and is similar in structure and location, but doesn't necessarily share the same purpose - These exist because of common ancestry - Scientists noticed animals with backbones (vertebrates) had similar bone structure - Limb bones develop in similar patterns - From land to water, the pattern is virtually identical in bone structure between arms, wings, legs, and flippers - These structures support the idea that the different animals descend from a common ancestor and serve as evidence of evolution

Phenotype

- An organism's physical appearance, or visible traits - Phenotypic evolution occurs primarily by mutation of genes that interact with one another in the developmental process - Environmental factors influence our phenotypes throughout our lives, and it is this on-going interplay between genetics and environment that makes us all unique

What are gracile australopithecines? (species and dates)

- Anamensis 4.2-3.9 myr - Afarensis 3.7-2.9 myr - Africanus 2.9-2.4 myr

Adaptation

- Animals in their biology and behavior make sense in the contexts that they live in - Ex: cats have binocular vision and a reflective surface in their retina that allows them to magnify low levels of ambient light so that they can see in very dim spaces during the night - Animals become adapted to their contexts that they live in through variations which are present in a species - Animal species differ in the sorts of biological features they possess and not all mammals, for example, have the same kinds of teeth - These specific biological features permit animals to be adapted to the way of life they follow

How do studies of primate behavior inform the study of human evolution?

- Anthropologists study living primates because by learning about species similar to us, we can learn about ourselves - Studying the behavior, anatomy, social structure, and genetic code of primates can reveal key differences and similarities between other primates and humans - From examining primates of many different species, we can determine how closely other species are related to each other as well as to us - By determining these relationships, we are able to gain a sense of our own evolutionary history, learning about shared common ancestors and how humans as a species developed and evolved over time. - We can see what traits are shared between all of the primates, what traits some primates have lost, and new traits which primates developed in order to survive in different environments

Transitional fossil

- Any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group - Many fossils show a clear transition from one species or group to another - Ex: Archaeopteryx was found in Germany in 1861 - It shares many characteristics with both dinosaurs and birds It provides good evidence that birds arose from dinosaur ancestors

Vestigial organ

- As evolution progresses, some structures get side-lined as they are not longer of use - Ex: the coccyx is a much reduced version of an ancestral tail which was formerly adapted to aid balance and climbing - Another vestigial structure in humans is the appendix - Vestigial structures are often homologous to structures that function normally in other species - Therefore, vestigial structures can be considered evidence for evolution, the process by which beneficial heritable traits arise in populations over an extended period of time - They provide evidence for evolution because they suggest that an organism changed from using the structure to not using the structure, or using it for a different purpose

Raymond Dart

- Australian anatomist and anthropologist - First person to identify the australopithecus africanus - The fossil was the of a young child from the site of T'aung, a limestone quarry in the Cape Provide of South Africa - Dart examined the fossil and found several features he believed identified this child as a human ancestor

Compare and contrast Australopithecines with early Homo. What features define these separate hominin grades? What are the similarities and the differences?

- Australopithecines = bipeds, with small, non-projecting canines, but they had small, ape-sized brains in a skull that was very ape-like, massive back chewing teeth and huge jaw muscles - By about 2 million years ago, members of our own genus, Homo, appear on the scene, probably evolving from one of the later australopithecines - Homo had bigger brains and smaller back teeth, but were still quite different from living humans - In comparison to the australopithecines, the early members of the genus Homo possess smaller molars and premolars in the side to side dimension, less massive mandible and maxilla with smaller muscle attachment areas and reduced robustness, and their brain volumes are in general larger with high more rounded brain cases than Australopithecines

Bipedalism

- Bipedalism is the distinguished characteristic of our lineage - moving by means of your two rear limbs or legs - Walking upright on two legs is the trait that defines the hominid lineage: Bipedalism separated the first hominids from the rest of the four-legged apes - Walking upright came before big brains in the evolution of humans - We have an especially efficient locomotive system - We use a lot less energy moving from place to place than a chimpanzee

Charles Darwin

- British natural historian and co-developer with Alfred Wallace, of a theory of evolution based on the concept of natural selection - Darwin accumulated information related to adaptation and natural selection but he was not the first person to think about it - Darwin participated in a 5 year voyage of exploration during which he made observations of the natural world which led to this theory of evolution - Darwin presented his theory of evolution and the considerable evidence he had amassed to support it in The Origin of Species - Genetics provides the information that Darwin did not possess on the underlying basis for variation and the introduction new biological features

What are some of the earliest tools in the fossil record? And what do they reveal about our early ancestors' cognition and behavior? How do we know that these are stone tools in the first place?

- By 2.5 million years BC, people started using a lot of stone tools - The first stone tools appear in the fossil record about two million years ago, as well as indications from scratch marks on animal bones that meat eating was occurring, but from hunting or scavenging is not known - South African robusts are found with stone tools, but it is unclear whether they, or a more advanced hominid, made the tools - It is clear from observations of chimps in their natural habitat that they are capable of making simple tools, like termiting sticks - It is reasonable to assume that the earliest members of the human line were at least as capable as living chimpanzees of making simple, non-durable tools. And of course, we will never find these objects in the fossil record. - The most useful tool made by our ancestors was a digging stick

Catastrophism

- Catastrophism is the theory that the Earth has largely been shaped by sudden, short-lived, violent events, possibly worldwide in scope - This is in contrast to uniformitarianism (sometimes described as gradualism), in which slow incremental changes created all the Earth's geological features - Used to explain the existence of the remains of extinct animals - Proposed that new life forms had moved in from other areas after local floods - Attempts to explain geologic history as a sequence of evolution and extinction of living organisms

Charles Lyell

- Considered one of the founders of modern geology - Based on his examination of the fossil record of shellfish in geological deposits, Charles Lyell said that the process of evolution is not slow and gradual (as Darwin had argued) but instead operates by rapid bursts of change and then longer periods of stasis - Darwin considered Lyell's views but ultimately rejected the notion of rapid evolution change

Watson and Crick

- Developed the double helix model of DNA - In 1953, J.D. Watson and F. Crick documented a model of the structure of the genetic material: DNA, thus providing the basis for the emerging understanding of the molecular basis for genetic processes

Allele

- Different forms of a gene - Alleles (variations of genes) are the basic unit of biological evolution - They not only define a species but also shape how that species changes generation by generation - Evolutionary processes depend on both changes in genetic variability and changes in allele frequencies over time

Diversifying selection

- Diversifying selection is selection against the mean expression - Forces a bimodal distribution of that trait - The effect of natural selectionwhen individuals at the extreme ends of the normal distribution curve have higher fitness than those near the center of the curve - Ex: birds that have a medium beak size cannot get into small places for food or have a big enough beak to break nuts so they just aren't able to eat as much and can't reproduce as much because of it - There are extremes on the low and high side and lower amounts in the middle

Homo erectus

- Earliest dated at east Turkana at 1.8-1.9 myr, and contemporary with the other early Homo species - Name was originally given to later-in-time fossils found in the last century in Java - H. erectus possessed very large brains (800ml), like H. rudolfensis, but also reduced in size back chewing teeth, like H. habilis - H. erectus is the most reasonable of the early Homo species to be considered ancestor to later in time hominids (modern humans)

Olduvai Gorge, Tanzania

- Earliest human remains have been found here - Holds the earliest evidence of the existence of human ancestors - Paleoanthropologists have found hundreds of fossilized bones and stone tools in the area dating back millions of years, leading them to conclude that humans evolved in Africa

Paranthropus boisei

- Early hominid with powerful jaws - An extinct species of very rugged, large-toothed bipedal hominin - Lived in eastern Africa about 1-2 million years ago - The features it shares or lacks with contemporary and earlier species makes relatively clear the relative diversification of the "robust" australopithecines

Great African Rift Valley

- Early in earth history, there was a continuation between the Mediterranean Sea and the Indian Ocean, which closed with the collision of Africa with the Eurasian Plate around 20 million years ago - This collision has had profound effects on the climate of East Africa and has resulted in the formation of Rift Valley geological features that preserve many of the earliest signs of our ancestors - Here, the presence of volcanic activity has permitted the use of radiometric dating techniques - The origin of our species is placed in East Africa (east of the Rift valley) and South Africa - The Rift Valley and its geology play a very important role in the preservation of an animal's bones after the creature dies - If a person dies near a river, they may be buried by sediments and then protected

Environment

- Environment includes what a species ate, how they sought after mates, etc - Adaptation takes place so that species can adapt to the environment they live in - Some variations are more capable of producing the useful behaviors in that context - Natural selection is neither absolutely positive or negative, but works relatively within environmental circumstances - What may be adaptive in one environment at one time may be maladaptive at other times and places - Species are constructed in their environments

What are 3 "vestigial organs?" Are all vestigial organs or features non-functional?

- Examples: wisdom teeth, appendix, coccyx - A vestigial structure may retain lesser functions or develop minor new ones - In some cases, structures once identified as vestigial simply had an unrecognized function

Homo erectus in Java

- First discovery by Eugene Dubois, who went to Java to find the 'Missing Link' - After the initial discoveries by Dubois, many additional Homo erectus fossils have been found at a number of sites - When H. erectus lived on Java, the island was part of mainland Asia, connected because of the drop in sea levels brought about by glacial activity in the Northern Hemisphere - The fossils are found in the sediments in the river in Java but they are hard to be dated

Description of Ardipithecus ramidus

- Forest ape 4.4 myr - It has the anatomy of a biped but with an opposable big toe - it used the trees as part of its adaptation - It has none of the specialized anatomical traits in the wrists and hands of the knuckle walking African apes - It has small non-projecting canines, typical of the members of the hominin lineage - The size of its back teeth are significantly smaller than the huge chewing teeth of the later australopithecines - Their brain size, at 330-350 ml. is within the range of the chimps

Gregor Mendel

- From 1856-1863, Gregor Mendel cultivated 29,000 pea plants to investigate how evolution worked - He figured out the basic principles of genetics - He showed that offspring received characteristics from both parents but only the dominant characteristic trait was expressed - Genetics provides the information that Darwin did not possess on the underlying basis for variation and the introduction new biological features - Genetic data answers fundamental questions about how hereditary material is transmitted across generations.

What is gene flow versus gene isolation? What are examples we have talked about in class that refer to this phenomena?

- Gene flow versus gene isolation = gene flow is when populations mix so that their genes intermingle while gene isolation is when populations do not intermingle with those outside of their group so that there is a very linear progression of features - Examples would be current populations in Mali with very little genetic similarity to contemporary population, which may indicate some kind of gene isolation

Switch genes

- Genes that turn on or off other genes during embryonic development - We have switches in our genes that allow us to use genes in one place and not another - When one gene is turned on, a whole new species is created - This can explain how one creature can become another creature by losing its legs - There is a switch that helps form the key human attribute of our thumb

What is the difference between genotype and phenotype? Give an example of each

- Genotype = the genetic constitution of an individual organism - Ex: a chart of a particular living thing's chromosomes, or DNA molecules responsible for various genetic traits - Phenotype = the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment - Ex: height, wing length, hair color

How do gorillas and chimpanzees locomote? How do humans locomote? Can we assume the last common ancestor between humans and chimps got around the way modern humans or modern chimps did? Why or why not?

- Gorillas and chimps both are knuckle-walking - Humans are bipedal -

Louis Leakey

- His work was important in demonstrating that humans evolved in Africa** - Made many fossil discoveries with his wife of early fossils in Africa - He also fostered field research of primates in their natural habitats, which he saw as key to understanding human evolution (studied a lot of Jane Goodall's work)

Brain volume in modern homo sapiens, australopithecus and chimpanzees

- Homo sapiens: 1200-1400ml - Australopithecines: 400-500 ml - Chimpanzees: 375 ml - The body had to change to accommodate these changes - The evolution of Homo sapiens over the past two million years has been marked by a steady increase in brain size, but much of it can be accounted for by corresponding increases in body size

Directional selection

- In a population, there is a selection for a variant so that that variant becomes dominant in that species over time due to differential reproduction - The effect of natural selection when individuals at one end of the normal distribution curve have higher fitness than individuals in the middle or at the other end - Ex: beak size increases reproduction abilities because they can get more resources in the environment so Finches developed bigger beaks over time

Significance of Ardipithecus ramidus

- It has been linked to the australopithecus and homo by nonhoning canines, a short basicranium, and postcranial features related to bipedality - These findings were hugely significant in terms of how we view the evolution of the earliest hominins and the physical appearance of the last common ancestor of humans and chimpanzees - Analysis of the skeleton reveals that humans did not evolve from knuckle-walking apes, as was long believed - It also indicates that chimpanzee evolution underwent high degrees of specialisation since diverging from the last common ancestor

Problems with studying hunter gatherers

- It's an ahistorical approach to anthropology (the changeless past) - Hunter-gatherers remained remote until anthropologists penetrated their lives - The "Noble Savage" approach (idea that these are pristine people without fault so if we can go back and capture that, we can capture what humanity is) - Living people are not fossils - Hunter-gatherers today live in a world of non-hunter-gatherers - There are many effects of Western resources/values

Why are the cave deposits in South Africa harder to date than the African rift valley?

- It's hard to understand fossils in South Africa because they don't form in order of age - The ones on the bottom are not necessarily older than the top ones because the new ones often form on the top and fall to the bottom side - In East Africa, many early hominin sites are associated with the Rift Valley. Here, the presence of volcanic activity has permitted the use of radiometric dating techniques - In South Africa, australopithecines are found in cave deposits and are much more difficult to date

James Hutton

- James Hutton and Charles Lyell are considered to be the founders of modern geology, based on the development of the concept of uniformitarianism, the idea that changes in the topography of the earth's surface are the result of the slow and gradual but constant operation of natural processes - Hutton argues that members of species vary, and that when the environment changes over time, those individuals best adapted to the new environment will survive, while those poorly adapted will perish - Thus, a process of natural selection (Hutton did not use this term) inevitably leads to change within species over time

Linnaen taxonomy

- Kingdom, Phylum, Class, Order, Family, Genus, Species - This is a way of organizing living things in a descending hierarchy of categories - This allowed for a classification system for the natural world to standardize the naming of species and order them according to their characteristics and relationships with one another

Natural theology

- Knowledge of God based on observed facts and experience as separated from divine revelation - Natural theology explains adaptation by supernatural action - as a creation of god - Natural theologians explained the properties of nature theologically (i.e. by direct action of God) - They were highly influential from the 18th century until Darwin

Robust Australopithecines

- Known for the rugged nature of their chewing apparatus (large back teeth, large chewing muscles, and a bony ridge on their skull tops for the insertion of these large muscles) - Huge back chewing teeth - Larger jaws and jaw muscles, sometimes with a crest on the top of the skull for additional surface area for the major chewing muscle - South African robusts are found with stone tools, but it is unclear whether they, or a more advanced hominid, made the tools

What anatomical modifications had to take place to accommodate for larger brains?

- Large brains mean large heads, making childbirth more difficult and painful for human mothers than for other primates - A mutation in our jaw muscle allows the human skull to keep expanding into adulthood, creating a bigger space for our brain

Zhoukoudian H. erectus site

- Located in North China, Zhoukoudian is the most northerly of the early Homo sites, though it is unclear whether the hominids actually occupied the cave during the winter - If so, it would be the first indirect evidence for the use of clothing - Along with fossil bones of about 45 individuals, there are animal bones with cut marks and burnt bones indicating the use of fire - Evidence suggests a long term but intermittent occupation of the site between 600-400,000 yr - No evidence for burials

Macro vs Microevolution

- Macroevolution = long time scale events that create and destroy species - Microevolution = short time scale events (generation to generation) that change the genotypes and phenotypes of populations

Mosaic environment

- Many different kinds of ecozones in relatively small geographic space - Early hominin environments = spotty, distinct micro environments (mosaic environments) - In Kenya, there is more genetic diversity than in all of Asia because of all of these different kinds of environments

What is a mosaic environment? Why is it important to the study of human evolution?

- Many different kinds of ecozones in relatively small geographic space - Early hominin environments = spotty, distinct micro environments (mosaic environments) - The mosaic habitat was preferred by hominins so we find a lot of fossil evidence here - In Kenya, there is more genetic diversity than in all of Asia because of all of these different kinds of environments - Since early hominins inhabited these places, it is important to study them to learn about those species

Hadar, Ethiopia

- Many fossils, and other evidence, from two sites in East Africa: Hadar (Ethiopia) and Laetoli (Tanzania) - At Hadar (3.2-2.9myr), many fossils have been found including the most complete australopithecine known: about 40% of a skeleton called 'Lucy'

Laetoli, Tanzania

- Many fossils, and other evidence, from two sites in East Africa: Hadar (Ethiopia) and Laetoli (Tanzania) - Volcanic eruptions were very common in the developing Rift Valley, resulting in the accumulation of sometimes enormous amounts of volcanic ashes - These ashes are very fine, silt-like materials, and they played a central role in the preservation of footprints at Laetoli, in northern Tanzania, from about 3.7 million years ago - This volcanic material can be dated to find very accurate time frames to find the dates of bones or fossils

Why are the figures Gregor Mendel, Thomas Henry Huxley, Carl Linnaeus, Jean-Baptiste Lamarck essential to Darwin (and Wallace) to develop the theory of Evolution?

- Mendel figured out the basic principles of genetics - Huxley documented the similarities between humans and chimps - Linnaeus is the father of taxonomy, which is the system of classifying and naming organisms - developed the hierarchical system of classification of nature - Lamarck showed how environment contributes to evolution as organisms alter their behavior in response to environmental change - These ideas help Darwin because they add the missing pieces to how evolution works

Homo sapiens

- Modern humans - During a time of dramatic climate change 300,000 years ago, Homo sapiens evolved in Africa - Like other early humans that were living at this time, they gathered and hunted food, and evolved behaviors that helped them respond to the challenges of survival in unstable environments

Gracile Australopithecines

- More lightly built chewing apparatus; likely had a diet that included more meat than that of the robust australopithecines - Best represented by the South African species A. africanus - They also possessed very large teeth for their body size, and both kinds of australopithecines had thick enamel on their teeth and also very heavy dental wear - Best guess is that the first members of the genus Homo evolved from an australopithecine, probably a gracile australopith, sometime around 2.-2.5 myr

Nariokotome

- Nariokotome on the west side of Lake Turkana = where the most complete skeleton of an early hominid was found - Discovered in 1984, the skeleton, WT-15000, is that of an approximately 11-12 year old boy - Found eroding out from under the roots of a tree, up until the origins of deliberate burials, around 100,000 years ago, this is the most complete skeleton of our ancestors ever found - The skeleton does not reveal how this child died, but it possesses some very interesting biological features, including a very tall stature, a brain of 800+ ml, relatively small teeth, but robusticity that is greater than that of the presumed female

Punctuated equilibrium

- Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change - Punctuated equilibrium predicts that a lot of evolutionary change takes place in short periods of time tied to speciation events - Once the change happens, quite quickly, the species re-enters stasis with its new evolutionary adaptation

Discuss the relationship between phenotype, genotype, environment, and ancestry

- Phenotype = the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment - Genotype = the genetic constitution of an individual organism - Genotypes interact with the environment to create the phenotype - Ancestry helps determine the genotype because it influences what genes are passed on, then the environment influences how that interacts to create the phenotype

Descent with modification

- Principle that each living species has descended, with changes, from other species over time - Descent with modification is associated to limb structure - Ex: there are common features between whales and 4 limb creatures that you can see in their bone structure because they still have the remnants of the hind legs - If you have a child, you pass on your genes but your child does not get your exact genes, your genes combine with your partner's and make small changes or mutations along the way - This means that the gene pool is continuously adjusting based on who is reproducing and how their genes are combined during the production of each offspring - Over extended periods of time, evolution takes place

Thomas Henry Huxley

- Professor of Anatomy and staunch defender of Darwin's ideas - Using the comparative gross anatomy of humans and the African apes (chimpanzees and gorillas), plus the very few human fossils known at the time, Huxley documented the evidence for placing humans in an evolutionary world - In 1863 he published Evidence as to Man's Place in Nature - In addition to the detailed comparisons of the anatomy of chimps, gorillas and humans, documenting their extremely close similarities, he also briefly described the anatomy of the fossil from the Neander Valley discovered in 1856 - He is known as "Darwin's Bulldog" for his advocacy of Charles Darwin's theory of evolution

Dr Stephen Jay Gould is known for characterizing the record of macroevolutionary change as a record of "punctuated equilibrium"? What did he mean by this, and how does it contrast with a gradualistic view of evolutionary change?

- Punctuated equilibrium = long stable periods are interrupted by brief periods of more rapid change and once the change happens, quite quickly, the species re-enters stasis with its new evolutionary adaptation - Gradualism = the idea that changes in the topography of the earth's surface are the result of the slow and gradual but constant operation of natural processes

Extended Evolutionary Synthesis

- Says we should be more encompassing about the evolutionary process - Species are constructed in their environments, they are not just a template or genotype - Evolution is an integration of ow physical development influences the generation of variation, how environment directly shapes organisms, how organisms modify environments, and how organisms transmit more than genes across generations - We construct our environments simultaneously with interacting and changing in those environments - Parent-offspring similarities result in part from parents reconstructing their own developmental environments for offspring

Stabilizing selection

- Stabilizing reproduction is selection against both extremes of the variation - There is a narrowing of the range in variation which less extreme ends of the variation - The effect of natural selection when individuals near the center of a normal curve of distribution have higher fitness than those at the extremes - Ex: both low birth weights and high birth weights are associated with negative outcomes in humans - Selection against both extremes keeps the curve narrow and in the same place

Taung

- The Taung child is the fossilised skull of a young Australopithecus africanus - The Taung Child has historical and scientific importance in the fossil record as the first and best example of early hominin brain evolution - It exhibits key cranial adaptations found in modern human infants and toddlers - It was among the first early human fossils to be found in Africa

Canine reduction

- The combined effects of improved cutting, pounding, and grinding tools and techniques and the use of fire for cooking surely contributed to a documented reduction in the size of hominin jaws and teeth - Unlike those of Paranthropus and Australopithecus, the teeth of Homo became smaller over time - Our ancestors used canines to fight male rivals for mating rights - Over time, human species evolved smaller and smaller canines as we stopped using our teeth as weapons - Reduction of sexual dimorphism->less male-male competition -> different social interactions

Pan troglodytes

- The common chimpanzee, a living African ape - Genetic studies indicate that chimpanzees are probably humans' closest living relative (~98% genetic similarity) - Behavioral studies indicate that chimpanzees can make and use rudimentary tools, suggesting that this capacity may have been shared with our common ancestor

Sahelanthropus tchadensis

- The earliest pre-australopithecine species found in central Africa with possible evidence of bipedalism - An extinct species of homininae dated to about 7 millions years ago - S. tchadensis has numerous derived hominin features and is therefore the oldest known human ancestor after the split of the human line from that of the chimpanzees

Oldowan

- The earliest stone tools. Simple chopping tools and sharp flakes - Oldowan tools date to about 2.4 million years ago - These tools were probably made by Homo habilis - The Oldowan represents the first instances of technological innovation in human history, where our ancestors first began to enhance their biological abilities with the manufacture of stone tools - This speaks to an important milestone in the evolution of our ancestors

The first stone tools

- The first stone tools appear in the fossil record in East Africa about 2.5 myr. They are river pebbles with flakes chipped off to produce a cutting edge - These first tools mark the beginning of the Paleolithic (do not confuse with Pliocene or Pleistocene). Later on, tools will become far more complex, sophisticated and well made - There is debate about the precise level of neurological abilities necessary to produce stone tools made to a pattern - The stone age or Paleolithic is divided into three stages, Lower, Middle, and Upper, which correspond to developments in tool making skills and complexity

Evidence of evolution

- The fossil record - this shows there is extinct life and we can find the relationship between these distinct forms of life and our living forms - The geographical distribution of living species - Homologous Structures of Living Organisms - Similarities in the early stages of embryological developments between different species

Genotype

- The genetic constitution of an individual organism - Natural selection acts on the phenotype, but evolution is a change in the frequency of alleles in a population over time, a change in genotype - Natural selection acts on phenotype, but it is the connection to genotype that makes it the mechanism of evolution

Uniformitarianism

- The idea that changes in the topography of the earth's surface are the result of the slow and gradual but constant operation of natural processes - Made by James Hutton and Charles Lyell - The principle that we can infer long term trends from those we have observed over a short period - It is possible to imagine, by extrapolation, that if the small scale processes we have seen were continued over a long enough period they could have produced the modern variety of life

Compare and contrast (and list the species and dates): gracile and robust Australopithecines (genera Australopithecus and paranthropus)

- The major differences in the two forms can be seen in the size of the temporal and masseter muscles and their attachment areas and especially in the forward projection of the cheek region in the robust guys - This is a direct functional result of the need to effectively utilize the huge back teeth which are anchored into the very large jaws by big roots - Separated by the powerness of the chewing muscles - Gracile forms and robust forms continue to be found in east and south africa - Some anthropologists believe there are too many differences between the robust and gracile australopithecines for them to placed in a single genus, Australopithecus - The robusts, with their huge chewing teeth and muscles, as very specialized creatures, deserve a genus of their own, Paranthropus

Problem with using chimps to study our own evolution

- The major problem with this is that living chimps are the result of an evolutionary history as long as ours, and they may have changed as profoundly as we have - There is not a single fossil bone documenting the evolutionary history of either chimps or gorillas

Fossilization

- The process by which a plant or animal becomes a fossil - We mostly rely on fossil records to show us the diversion of us from our most recent common ancestor from chimpanzees - The fossil record shows there is extinct life and we can find the relationship between these distinct forms of life and our living forms - Fossils in different layers of rock (sedimentary rock strata) showed evidence of gradual change over time

Natural selection

- The process whereby organisms better adapted to their environment tend to survive and produce more offspring - Natural selection is the differential survival and reproduction of individuals due to differences in phenotype - It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations - Natural selection leads to evolutionary change when individuals with certain characteristics have a greater survival or reproductive rate than other individuals in a population and pass on these inheritable genetic characteristics to their offspring

Paleontology

- The study of fossils - The fossil record shows us the sequence of historical changes in organisms - By studying fossils, scientists can learn how much (or how little) organisms have changed as life developed on Earth - Paleontology allows us to place living organisms in both evolutionary (life-historical) and geological (earth-historical) context

Archaeology

- The study of human history and prehistory through the excavation of sites and the analysis of artifacts and other physical remains - Behavioral change was likely a driving factor in the evolution of our species, and archaeology therefore plays a central role in understanding human origins - The material record of human behavioral innovation provides an essential learning tool for understanding human behavioral diversity - Archaeology provides the long-term perspective of human behavioral change and is the necessary complement to other approaches that emphasize biological change

Stratigraphy

- The study of rock layers and the sequence of events they reflect - Fossils in different layers of rock (sedimentary rock strata) showed evidence of gradual change over time - You can use rock ages to date when fossils came from by knowing how old the rock that the fossil is in is

Gradualism

- The theory that new species evolve from existing species through gradual, often imperceptible changes rather than through abrupt, major changes - Small variations that fit an organism slightly better to its environment are selected for: a few more individuals with more of the helpful trait survive, and a few more with less of the helpful trait die - Very gradually, over a long time, the population changes - Change is slow, constant, and consistent

What are 3 features that modern humans might share with Neanderthals, revealing a shared common ancestor?

- There is great genetic similarity - Average Neanderthal men stood around 5 ft 5 in and women 153 cm 5 ft tall, similar to contemporary humans - Maximum lifespan, and the timing of adulthood, menopause, and gestation were most likely very similar to modern humans - Neanderthals were likely able to survive in a similar range of temperatures as modern humans while sleeping

Overview of australopithecines

- They are characterized by a combination of ape-like and human traits - They were bipeds, with small, non-projecting canines, but they had small, ape-sized brains in a skull that was very ape-like - Uniquely, they had massive back chewing teeth and huge jaw muscles - We know virtually nothing about their adaptation, diet, social organization or general behavior

Gatherer-Hunter

- They would hunt animals and gather things from their environment based on a super well-honed understanding of their environment - They had very flexible mapping of their food sphere/environment - Their relationships with animals were very complex - They understand how to manipulate seeds and how plants reproduce but they aren't planting them themselves - Hunter-gatherer societies could open a window into understanding early human cultures - For the vast stretch of human history, people lived by foraging for wild plants and animals

The Beagle

- This is the boat that Darwin sailed on from 1831-1836 - They went along the coast of South America - It was designed to measure the amount of hours and minutes since they left England so that they would always tell how off they were from England time to measure the longitude that they were at - On the Beagle, they would get cups of sediment from the coast along South America to see what the composition was of the sediment along the coast - This would allow people in the future to gather sediment and compare it to these samples to tell where they were

Alfred Russell Wallace

- Wallace was a natural history collector, a working man - He is best known for independently conceiving the theory of evolution through natural selection; his paper on the subject was jointly published with some of Charles Darwin's writings in 1858 - This prompted Darwin to publish his own ideas in On the Origin of Species - One of the leading evolutionary thinkers of the 19th century and made many other contributions to the development of evolutionary theory besides being co-discoverer of natural selection

Homo habilis

- When established in 1964, considered to represent the evolutionary transition from the australopithecines to Homo - Name means 'handy person' - Fossils are dated to 1.7 - 1.8 myr. - Initially from Olduvai and now from East Turkana

What accounts for larger human brains compared to our ancestors?

- When humans began to walk upright and make simple tools, brain size increased, but only slightly - When humans started spreading around the globe, encountering many new environments on different continents, this led to an increase in brain and body size - Human brain size evolved most rapidly during a time of dramatic climate change - Larger, more complex brains enabled early humans of this time period to interact with each other and with their surroundings in new and different ways - As the environment became more unpredictable, bigger brains helped our ancestors survive - A large brain capable of processing new information was a big advantage during times of dramatic climate change

What is the basis of Evolution by Natural Selection?

1. Adaptation 2. Reproduction and Mortality 3. Variation

What are the four major mechanisms of evolution (according to the MES)? How do they each increase or decrease variation in a population?

1. Developmental bias = how physical development influences the generation of variation 2. Plasticity = how environment directly shapes organisms 3. Niche construction = how organisms modify environments 4. Extra-genetic inheritance = how organisms transmit more than genes across generations

What are some of the major differences between the skeletons of anatomically modern humans and those of our early hominid ancestors

Bipedalism Larger cranium Wider pelvis Jaw muscles that allow for skull growth Brain size is much bigger for modern humans

Typology

Typology provides an organisational tool to enable the archaeologist to group artifacts into bodies which have "demonstrable historical meaning in terms of behavior patterns"