Exam 1 Study Guide
Exam 1 Study Guide ANTH 1001
Popular in Introduction To Biological Anthropology
Laura Castro Lindarte
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This 25 page Study Guide was uploaded by Laura Castro Lindarte on Saturday October 1, 2016. The Study Guide belongs to ANTH 1001 at George Washington University taught by W. Andrew Barr in Fall 2016. Since its upload, it has received 283 views. For similar materials see Introduction To Biological Anthropology in Biology/Anthropology at George Washington University.
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Date Created: 10/01/16
Date of Exam: October 5, 2016 Exam 1 Study Guide: ● Exam format will be multiple choice and fill in the blank ● Topics on exam are mostly from lecture and labs, but some from reading ● NO CHAPTER 7 ON EXAM ● Chapter 1: What is Biological Anthropology? ○ Anthropology = study of humankind in a CROSS-CULTURAL c ontexts ○ 4 major subfields: 1. Socio Cultural: study of human societies i n cross-cultural lense a. Differs because emerge in day to day life (participant observation) b. Culture: shared behaviour and values that are learned in society 2. Archeology: s tudy of material remains of past cultures 3. Linguistics: study of one aspect of cultural- l anguage (origins, structure and usage) 4. Biological: tudy of humans as biological organisms with an EVOLUTIONARY FRAMEWORK ○ Subfields of Biological Anthropology: 1. Primatology: tudy of close relatives (primates) 2. Paleoanthropology: s tudy o NCIENT human origins 3. Skeletal biology and paleoanthropology: tudy of bones and the change of diseases 4. Human biology: f actors that underl iversity, growth and reproduction 5. Forensic Anthropology: sing tools to help legal/medical context 6. Anthropological genetics: l ook at genes and their effect 7. Evolutionary neuroscience: ow human b rain re unique ● Chapter 2: Evolutionary thought ○ Science: an approach to gaining information about natural selection phenomenon through observation and experimentation ■ It is EMPIRICAL → knowledge through observing ○ Steps of science: 1. Observation and description of phenomena 2. Formulating h ypothesis to explain observation 3. Hypothesis testing gainst empirical evidence (i.e data) a. Go out and test our explanation b. In historical sciences like anthropology you use observations as experiments since you cannot do hand-on experiments 4. If hypothesis can’t be falsifiabl heory (largely supported sets of generalization that allows us to predict what happens in specific conditions) ill be formed ○ Science is a self-correcting process because of falsifiable ■ All based on looking at data to try to prove wrong, never prove right ○ SCIENTIFIC theory is: ■ Established ody of knowledge ■ Based on observation of f actual events and collection of factual data → attempt to explain how things occur ■ Based on TESTABLE hypothesis → g ets tested over and over ○ Biological evolution: istory ■ Ancient Greece: a. Anaximander: i. Looked for N ATURAL causes ii. Before supernatural causes used for natural phenomenons iii. Notion of change ( human and other animals came from fish) b. Plato: i. “Eidos”= ideal forms o f objects that are imperfectly imitated in real world → diversity is all the objects trying but failing to be eidos ii. Fixity of Species: species have a defining essence that is FIXED AND UNCHANGEABLE c. Aristotle: i. Appreciated organic diversity → o bservations ii. Organized and classified organisms into “ scala naturae” (Great Chain) of beings with HUMANS ON TOP ■ The Middle Ages: a. Most of people could not read/write b. Scientific knowledge was MONOPOLIZED BY CHURCH c. Species were created in a fixed way and science just about observing it i. Argument of design = all features of animals were seen as perfectly designed for purpose ■ In the East: a. Li Shih-Chen: i. Chinese naturalist ii. Organisms influenced by environment and would change due to it iii. Binomial system of naming organisms ■ Renaissance: a. Careful description and i ncreased knowledge of anatomy b. Explorers traveling and d iscovering new species c. New technology to c ollect data to prove church wrong d. Galileo Galilei: i. Established a systematic empirical approach to look at natural phenomena ii. Confirmed Copernicus's idea that Earth wasn’t center of the universe 1. Important because showed that you can question the church e. John Ray: a. Defined s pecies as group of animals that could reproduce with each other b. Species share similarities with other species ( created genus to classify this) ● Carolous Limaneus: a. Wanted to describe structure of ALL living things i. Kingdom → Phylum → Class → Order → Family → Genus → Species (two last things is the name) b. Systema Naturae- binomial system to classify organisms ■ 16 - 19th Century: a. Compte De Buffon: Historie Naturelle i. Animals that go to new environment change in response 1. Did not talk about HOW they change ii. External environment is important for biological change b. Jean Lamarck: i. First to propose mechanism of evolutionary change to explain diversity ii. All species came from God and changed over time based on how much certain parts of body were used → c hanges passed on iii. Inheritance of Acquired Traits: evolution occurred in one organism’s life c. George Cuvier: i. Described changes in the assemblages of b iological organisms were tied to changes in rock layers ii. Catastrophism: catastrophes leads to extinctions d. Charles Lyell: P rinciples of Geology i. Uniformitarianism: environmental phenomenon that happens now and reshape Earth did so in part too ii. The landscapes seen presently could only occur in E ARTH WAS OLD 1. Gave Darwin the time frame he needed ○ Both Darwin and Wallace looked at available information and s ynthesized it to come up with framework of natural selection ○ Charles Darwin: 1809-1882 ■ Born to an upper-class British family and ent to medical school and was exposed to Lamarck’s ideas → not good at medical school so he decided to study theology (study of religion) ■ At age of 22 he graduated and was recommended to travel as naturalist in HMS Beagle with captain Robert FitzRoy a. They were most interested in taking specimens from South America b. Darwin was on HMS Beagle from 1831 to 1836 ○ Experiences on HMS Beagle that influence Darwin: 1. Observation of diversity of flora and fauna 2. Experienced earthquake in Chile a. Made him interested in geology (specifically how the earth changes) 3. In Argentina, Darwin c ollected fossils of extinct animal hich made him become interested in why they disappeared and how biology changes 4. Observation of diversity in ground finches across the Galapagos Islands (volcanic islands off the coast of Ecuador), noticed that: a. Animals and plants were similar to those in mainland b. Other mainland animals did not exist at all on the islands i. Large mammals were not found on islands c. Some animals on the islands were not found on the mainland i. Giant tortoise was not found on mainland d. Different species existed on different islands i. Believed this was because of environment ii. Ex: dry land tortoise had saddle shell to be able to get food from high places while other tortoises had done shape shells because they were able to find food on the ground iii. Ex: Darwin collected 13 finches from islands with similarities but many differences, were all different species 1. Beaks matched food available in islands where they lived 2. One ancestor finch probably got to island and underwent adaptive radiation based on environment 5. His reading of T homas Malthus’s essay on “Principle of Population” a. Malthus discussed population growth because based on his calculations the uman population can grow in exponential rate while the amount of food cannot meaning that sooner or later we would run out of food for everyone b. In reality world populations were stable because of “struggle for existence” ( limited resources limited how much population could grow) c. Darwin concluded that INDIVIDUALS of species with adaptations are more likely to reproduce/survive 6. Observation of the power of artificial selection to produce different domesticated animals ( looked at the variation in the domesticated pigeons) ○ Darwin develops his theory of Natural Selection: ■ 1836: Darwin came back from HMS Beagle ■ 1844: Darwin prepares his first lengthy “sketch” on his f evolution by means of natural selection a. 20 years pass because he publishes it because he did not want to upset religion ■ 1858: Darwin received anuscript by Alfred Russel Wallace who had CONCEIVED EVOLUTION BY MEANS OF NATURAL SELECTION → looking for advice a. Shows that evolution was a product of its time because two people came up with the same idea ■ 1858: Both present a paper to the LINNEAN SOCIETY IN LONDON that showed the theory ○ “On the Origins of the Species By Means of Natural Selection” (1859) ■ Biological evolution i ACT ■ Common descent with modification a. Proposed mechanism of how ALL species evolved from one ancestor b. Animals that had more similar features were closely related meaning that they had a more recent common ancestor ■ Gradualism: gradual change through time ■ NATURAL SELECTION IS MECHANISM OF EVOLUTION ○ Natural selection: the mechanism ■ Observation: species produce more offspring than can be supported ↓ ■ Deduction: limited resources lead to competition ■ Observation: there is biological variation among individuals in species. The characteristics of some seem more favorable adapted to the environment ↓ ■ Deduction: different survival and reproduction of those with better traits. They are more fit. ■ Deduction: these individuals are more likely to reproduce and those traits will get INHERITED by offspring. Traits will become more common over time ■ Fitness: reproductive succes how many offsprings an individual has) ■ Adaptation: changes in response to new/varying environment pressure a. In evolution, changes occur to a whole population not just individuals b. Occurs in response to articular environmental conditions ○ Examples: ■ Pepper month in England: a. Pre-industrialization: light were more advantaged because could blend better into trees so would survive more and majority of population was light b. Post-industrialization: dark becomes more advantaged because can blend into dirty trees so there is a shift in the population to prefer dark moths ■ Finches in Galapagos: a. Medium ground Finch with small beak begin to die off during a drought because there were less small seeds to eat so big beak individuals were more likely to get food b. After drought the average beak depth of finch is longer c. Population shifts again to favor smaller beaks because the small seeds began to appear again and other large beak individuals came from other islands which created competition ● Chapter 3: Mendelian Inheritance ○ Pre-DNA concept of heredity: ■ Blending theory of inheritance: hen you have a mother with one characteristic and a dad with another the characteristic lend in offspring a. Parental contribution is averaged out in offspring b. Variations get blended out so they don’t survive over time because traits would disappear ○ Gregor Mendel: 1 822-1884 ■ Undertook a s ystematic investigation of inheritance in pea plants ■ Demonstrate particulate inheritance (inheritance occurs because specific particulates passed down from parents to offspring) ■ Easier to control reproduction in pea plants than others because e asy to control pollination of plants ■ Pea plants have a v ariation in a number of different traits: a. Round or wrinkled seeds b. Yellow or green seed interiors c. Purple or white petals d. Inflate or ripe pods e. Green or yellow unripe pods f. Axial or terminal flowers g. Long or short stems ■ Easy to develop p ure-breeding lines for pea plant ecause have simple inherited traits ○ Mendel’s Experiments: a. Monohybrid cross: crossing TWO PUREBRED and F 1 generation all had yellow seeds despite parent variation i. Yellow and green produced yellow (DID NOT BLEND) b. F generation: self-fertilization of F 2 1 i. The green variant APPEARED UNCHANGED ( about 25%) ii. Called variant in F1 ominant trait and reappeared variant recessive trait c. Dihybrid cross: 2 traits seen in combo ○ Still 3 to 1 ratio ○ Mendel's Conclusions: ■ Particulate inheritance: a. Each heredity characteristic by particles “ unit factor” that exist in pairs (one from each parent) b. There factors remain discrete (unchanged) regardless of external appearance ( no matter if variant not in F , info was still there) 1 ■ Dominance: a. When and different unit are together, o nly one is shown physically (DOMINANT) while other is not (RECESSIVE) b. There must be t wo copies of the recessive factor for it to be expressed c. Phenotype: PHYSICAL characteristics (can be seen) d. Genotypes: GENETICS b asis of phenotype (influences what is seen) i. Homozygous: 2 copy of SAME TRAIT ( pure-breeding) ii. Heterogeneous: h as 2 IFFERENT TRAIT but only SHOW ONE ( hybrid) e. Seed color: yellow (dominant), green (recessive) f. g. Can use P unnett Square: h. Overall in F2 ou would see 3 to 1 rat 25% recessive) ■ Law of Segregation: during formation of sex cell, the pair unit in parent is separated RANDOMLY (equal likelihood that it will recessive or dominant) ■ Law of independent assortment: istribution of one pair of factors doesn’t influence other a. Traits are passed down INDEPENDENTLY AND SEPARATELY→ one trait doesn’t influence other traits ○ Chromosomes and cell division: ■ Eukaryotic cells are those with nucleus that can be multi-cell or single cell organism ■ Inside the nucleus you can see hromosomes are seen → m ade out of DNA (deoxyribonucleic acid) a. Usually not seen, only when cell will divide, before there is a soup of DNA ■ Gene: enetic material th ncodes to particular traits ■ Locus: where gene is on chromosome ■ Alleles: ALTERNATE version of gene ■ Different size, shape, and pattern on chromosomes, an arrange chromosomes into KARYOTYPE → list of homologous pair (one from father and one from mother) a. Have same gene but can have different alleles ■ Human have 23 pairs of chromosomes a. 22 pairs are autosomes and 1 pair is sex chromosomes (female=XX, male=XY) b. Y has testees determination factor to change development of fetus to make it a male c. Lots of genes in X not seen in Y leading to sex-linked traits ■ EACH SPECIES HAS OWN NUMBER OF CHROMOSOMES ■ Somatic cells: component of body tissues a. Are diploid so have both chromosomes of each pair b. 23 pair (46 in total) ■ Sex cells (gametes): a. Haploid: one member of each chromosome i. Zygote: union between sperm and ovum ii. 23 chromosomes in total b. Ova = egg cell in female ovaries, sperm = sex cells in male testes ■ Mitosis: cell division resulting to 2 DAUGHTER CELLS THAT ARE IDENTICAL TO EACH OTHER AND PARENTS (somatic cells) 1. Interphase: ormal life then DNA is replicated 2. Prophase: c hromosome appear (X) with identical chromide 3. Metaphase: chromosomes line up 4. Anaphase: c hromosomes separated where chromatids meets (move to opposite side of cell) 5. Telophase: c ell split resulting in 2 cell ame amount of DNA than in beginning ■ Meiosis: produce sex ce 2 round of division) 1. Reduction Division: a. Interphase: NA replicate b. Phosphate 1: creation of chromosome and crossover: one chromatid cross with other and exchange gene i. Result in chromatid that are different from what was present before ii. Increases variation because not only pass on parent chromosome but new ones iii. Provide raw material for natural selection c. Metaphase 1: chromosomes align in h omologous pair and get torn apart (random what side each pair is on) d. Anaphase 1: e ach get one chromosome of pair e. Telophase 1: c ell splits f. Interkinesis 1: 2 haploid daughter cells 2. Second division: IMILAR to mitosis except no replication of DNA in interphase a. Results in 4 haploid gametes cells that are GENETICALLY DISSIMILAR b. Meiosis provides way of how Mendel’s laws occur: i. Law of segregation because meiosis line up randomly ii. Law of independent assortment APPLIES TO TRAITS ON SAME CHROMOSOME NOT IN DIFFERENT ONES ● Chapter 4: Genetics II: From Genotype to Phenotype ○ DNA is a nucleic acid: ■ Found in ucleus ■ STORES AND TRANSMITS INFORMATION ■ Made of smaller molecules called ucleotide a. 4 different bases purine = Adenine, Guanine; Pyrimidines = Thymine, Cytosine) → will interlock based on structure b. Phosphate + sugar (deoxyribose) + Nitrogenous base c. Purines have two rings, pyrimidines have one ring ○ Chargaff’s Rules: ■ Saw that similar proportion of Adenine and Thymine throughout and similar proportion of Guanine and Cytosine A=T, G=C) ○ Rosalind Franklin’s observation provided clues ■ James Watson and Francis Crick created DOUBLE HELIX STRUCTURE ■ Complementary bases important for replication ○ DNA functions: ■ Replication ■ Protein synthesis ○ Replication occurs during ell divisi originals strand separate riginal acts as TEMPLATE and attracts other loose bases around it to ave two identical copies) ○ Protein synthesis (genotype → phenotype) ■ Proteins play a tructural or active component in body ○ Protein made out of mino acids that link together into polypeptide c 20s ( different amino acids) ■ Shape determines behaviour of protein ○ DNA is recipe for sequence of amino acid ■ Every 3 bases will result in one amino a CODON) → SPECIFIC (a codon will always stand for a specific amino acid) ■ Different chains can be associated to create complex (multimeric) proteins ○ 4 bases can combine to make 64 codons but only 20 amino acids exist so there is some amino acids that are coded from more than one codon ○ Gene: sequence of DNA that arries information for synthesizing specific protein and occupy specific space in chromosome ( chromosomal locus) ○ Protein synthesis occurs in ibosomes outside of nucleus) but DNA cannot leave nucleus so transcription occurs to transfer message from nucleus to ribosome ○ Transcription: first phase of synthesis ■ Creation of messenger called NA → single stranded, ribose sugar and uracil bas instead of T it has U) ■ DNA unzip long section of DNA needed a. Just like replication, base pairs come in and fill in what is left and create complementary RNA strand called mRNA ○ Translation: Second phase ■ mRNA binds to ribosome ■ Codons are read by ribosome and tRNA comes in and brings amino acid to right place ■ tRNA binds to mRNA bring amino acid which bind together ■ Continues until you get to stop codon ○ DNA mutation: alteration of genetic code ■ Source of new variation, only make matter if they occur because in the gametes because only those will be passed on ■ Type of mutation: a. Chromosomal mutation: e xtra chromosome or deletion of a chromosome (problem with separation or merging) b. Point mutation: single letter is changed in DNA c. Duplication: odons are duplicated resulting in an extra codon i. New amino acid will be inserted d. Inversion: codons are in wrong order e. Deletions: l etter is taken out so all shift over so all codons change (frame-shift) ○ Frame-shift mutation: AGC TCC CTA T… → A CC AT Ser Arg Asp STOP ○ When mutation occurs to single letter it mi ot lead to change because error builds same amino acid (synonymous mutation) ○ Mutations may be functionally irrelevant (produce no change) but others are functionally significant ■ Many are lethal or negative, others neutral ■ Small proportions may be beneficial and confer SELECTIVE ADVANTAGES ○ Mendelian Inheritance looked a ingle gene with autosomal dominant/recessive model ■ Useful when looking at ualitative varia discrete categories) ■ Ex: seed color in peas, albinism ○ Codominance: both alleles i eterozygous are fully expressed → NEITHER DOMINANT OVER OTHER ■ Ex: ABO system: 3 alleles (ABO) with A and B being dominant so can have AB blood type, O is recessive to both (can only be expressed if homozygous oo) ○ Sex Linkage (x-linked traits): controlled by gen chromosome ■ Males only have one x chromosome so a ll alleles in X chromosome in male will be expressed no matter if dominant or recessive) ■ Ex: hemophilia, red-green color blindness ○ Polygenic traits: don’t follow Mendel’s rules because uantitative (continuous) variation that are influenced by many genes and environmental factors ■ Ex: stature, skin color, eye color ○ Pleiotropy: single gene influences multiple traits at same time ■ Ex: Marfan syndrome, don’t follow Mendel’s rules ○ Environmental effects: genes are not only fact any things in environment can affect phenotype ■ Genotype sets limit or chance for something to develop but might not ○ Type of genes: ■ Structural genes: will code for amino acid chain ■ Regulatory genes: ay control effect of other genes a. Homeotic genes: c ontrol tissue growth b. HUGE IMPACT→ human and chimps share 99% of DNA but very different, difference might be because of regulatory genes ○ Huge part of DNA ave no function: ■ Introns and exons: only exons pulled out to make mRNA while information are not ■ Splice variance ifferent on how genetic code is transcribed ■ Non-protein coding regions: a. Introns b. Pseudogenes c. Variable number tandem repeats and short tandem repeats ● Lab 3 Terms: ○ Cladistic: field of study in bio t ladogram to look at inheritance ○ Claude: group of species on cladogram that a elated ○ Taxon: group of organisms wit et of characteristics ■ Interchangeable with species ○ Characteristics divided in primitive or derived: ■ Primitive: shared betwee escendants and ancestors a. Aka: symplesiomorphic b. NOT HELPFUL TO LOOK AT RELATEDNESS ■ Derived: NOT SHARED with ancestors a. Aka: synapomorphic b. Better to look at shared derived traits (come after ancestor) when want to know if related ■ As you go back more will be derived and less primitive ○ Homologous feature: characteristic that are similar because both ancestors and descendants have it ○ Homoplasy: characteristics that are similar between species because of ENVIRONMENTAL DRIVERS ○ Catarrhinsubunit of primate ○ Dental formula: organize organisms based o eeth count ○ Obligate bipedality etter mode of movement is upright ○ Canine dimorphic: different between canines of male and female ○ ○ Parsimony: simplest way is right way ● Chapter 5: Forces of Evolution and Formation Species ○ Population: a group of organisms potentia apable of successfully reproducing ■ Individuals tend to choose mates from within group ■ The largest reproductive population is species, population can range from small group to whole species ○ Gene pool: sum of all allel arried by members of population ■ Can look at allele frequency (how many of each alleles seen) and genotype frequency (how many have specific combination of alleles) ○ Evolution: change in ALLELE FREQUENCY in population from one generation to the next ■ When allele frequency change then evolution has occurred, i f frequency if NOT changing then it is in GENETIC EQUILIBRIUM ( no evolution is occurring) ○ Hardy-Weinberg: model of genetic equilibrium ■ Null model: looking to see if volution is occurring to a specific allele → sets up frequencies when no evolution is occurring to compare observed frequencies to see if evolution is seen ■ Ex: dominant = A, recessive = a; f requency of dominant = p, frequency of recessive = q so p + q = 1 a. Number of alleles always double of number of individuals because all have two ■ Chances of AA → p x p = p ■ Chances of Aa or aA → p x q p x q ■ Chances of aa → q x q = q so… 2 2 p + 2pq + q = 1 (Hardy-Weinberg equation) ■ Assumes that mating is random, population are infinitely large → i f frequencies don’t go with equation then evolution occurs ■ Ex: population: 100 cats; traits : fur pigmentation; phenotype: black, orange, calico; genotype: BB, OO, BO (codominance) 1. Calculate observed genotype f requency 2. Calculate observed allele requency 3. Use the H-W formula to calculate e xpected genotype frequencies under conditions of NO EVOLUTION: p + 2pq + q = 1 BB → p = 0.45 = 0.2025 BO → 2pq = 2(0.45)(0.45) = 0 .4950 OO → q = 0.55 = 0.3025 4. Compare c alculated frequencies to actual frequencies: a. Since not same number and statistically significant difference then evolution is occurring and not favoring calico ○ Forces of evolution: actors occurring in natural population th ause changes in gene frequency over multiple generation 1. Mutation 2. Natural selection 3. Genetic shift 4. Gene flow 5. Nonrandom mating ○ Mutation: ■ Alternation of genetic material RANDOM) ■ Rare and give rise to new alleles ■ INCREASES VARIATION ○ Natural Selection: ■ Alleles that allow organism to reach reproduction age will be passed down (NOT RANDOM, based on survival) ■ This is where environmental changes come into play ■ Acts on phenotype and reflected in genotype 1. Stabilizing: aintains by a certain phenotype by electing against deviations from i acts on extremes) a. Ex: birth weight in human infants, underweight and overweight infants are more likely to die so middle weight infants are favored 2. Directional: election for greater or lesser frequency of given trait, one of the extremes is more popular a. Seen in Darwin’s finches changing beaks due to droughts 3. Disruptive: both extreme favorable but middle not less common) ■ DECREASES VARIATION ○ Genetic drift: change in gene frequency over ti ue by random factors ■ No natural selection or mutation, just luck ■ Sampling error effects ore likely to change i mall population ■ Population bottleneck: vents that make only a few survive so only their alleles survive a. Ex: Cheetahs are very similar genetically because bottleneck only allowed few to survive ■ Founder effect: individual leave and only their traits seen in population in new area ○ Gene flow: movement of individuals and genes b etween population ■ Make populations m ore similar to one another ○ Nonrandom mating: ■ Inbreeding: i ncreases frequency of homozygous of particular loci, decreases heterozygous of particular loci ■ Assortative mating: a. Negative: i ncreases frequency of heterozygous genotypes of particular loci, l ooking for similar individuals to you to mate b. Positive: increases frequency of homozygous genotypes of particular loci, l ooking for different individuals to you to mate ○ Microevolution: mall changes occurring w ithin a species uch as changes in allele frequencies ○ Macroevolution: l arger changes produced a fter many generations, uch as appearance of new species ■ Microevolution can lead to macroevolution if given enough time (accumulation) ○ Species concept debate: not one agreement on how to define what a species is and what is best mechanism for knowing if two populations are same/different species ■ Most commonly known is b iological species concept (BSC): roups of interbreeding natural population which are r eproductively isolated rom other groups ( can and will they reproduce in the wild) ■ Reproductive isolation: a. Physical barriers ( geographic) b. Intrinsic barriers physiology, behaviour) i. Ex: appearance or courtship rituals ■ Reproductive isolating mechanisms: a. Premating mechanisms: p rior to process i. Habitat isolation: l ive in different habitat in same ecosystem so d on’t come into physical contact ii. Temporal isolation: aving different mating season iii. Behavioral isolation: eproductive behaviour is different iv. Mechanical incompatibility: i ncompatibility of mating structures b. Postmating mechanisms: after physically mating i. Sperm-egg incompatibility: f emale body might attack sperm from other species or sperm can’t penetrate egg ii. Inviability of Zygote-fetus: i nstantaneous abortion of fetus iii. Offspring sterility: offspring not able to reproduce (ex: mule) ■ All in natural world, in captivity some might mate (ex: liger) ■ BSC can be hard to apply to some things like h ybrids, two species not being together over (location or fossil) so can’t be tested ○ Differences between species ccumulate through time ○ Recognition species concept: UNIQUE TRAITS that allow members to recognize each other do they recognize others as member of species?) ○ Ecological species concept: roup of organisms xploiting a SINGLE ECOLOGICAL ADAPTATIONS (hybrids won’t be as fit) ■ Species are in optimal fit zone for their environment, natural selection important ○ Evolutionary species concepts: efines o volutionary lineages with their own unique identity (is ancestral-descendant sequence unique to species?) ○ Morphological species concept: l ooks NATOMICAL SIMILARITIES, p roblem because species can be p olymorphic (have different traits) ■ Sometimes it is the ONLY one you can use because only have anatomical data ○ Major modes of speciation: ■ Anagenesis: volutionary change occurring in ne evolutionary line, difference occurring within one species (NO SPLITTING) a. Chronospecies: specific species within an anagenetic line ■ Cladogenesis: ne species PLIT to create different daughter species ■ Can both happen to one ancestor tree ■ Different processes of cladogenesis: a. Allopatric: ecause of OMPLETE geographic isolation i. Ex: fruit flies separated in lab ii. Most common iii. Divergence will occur often when population separated due to utation, genetic drift and natural selection b. Parapatric: because of ARTIAL geographic isolation i. Ex: hamadryas baboon and anubis baboon being different species but having big hybrid zone because still live close to each other ii. Divergence will occur often when population separated due to utation, genetic drift, nonrandom mating and decreased gene flow c. Sympatric: because of A BSENCE g eographic isolation i. No isolation ii. Divergence will occur often when population separated due to utation, natural selection, mate recognition and selective breeding ■ Niche: how species makes its living a. Species that live together need to have NICHE DIFFERENTIATION to avoid direct competition ( ex: primates different due to the different levels of the rainforest that they live in) ■ Adaptive radiation: ingle kind of organism iversifies to fill many different niches ■ Tempo of speciation can be: a. Gradualism: a ccumulated small changes ● Punctuated equilibrium taple for a LONG time then smart period of a lot of change ● Chapter 6: Human Variation ○ Concept of race more SOCIAL THAN BIOLOGICAL ○ How to break down species? ○ Humans are NOT very genetically diverse ■ Our perception of it ubjective bias (humans are good at seeing different in humans) ■ Chimpanzees show two to four times more genetic diversity than humans ■ Why? 1. Relatively recent BOTTLENECK event in human history 2. Gene flow is vast in human population compared to others a. Due to migration ○ “Race”: a group of populations hare certain characteristics that make them distinct from others ○ Some variations are eographically structure people will mate with those close to them) ■ Relationship between geography reflect gene flow ○ Apportionment of human diversity (Lewontin, 1972): ■ How much is variation is seen across geographical regions and how much within region? a. Only 10% of diversity see between large geographical regions, 85% seen WITHIN POPULATIONS ○ Term “race” is a typological and arbitrary concept which assumes that human variation can be classified in distinct gr NOT ACCURATE) ○ Skin color is what has gotten most attention ■ If you look at few specific populations it would be easy to categorize skin color into light, medium and dark BUT NOT THAT SIMPLE WHEN YOU LOOK AT MANY DIFFERENT GROUPS ( will see whole array) ■ Categorizing humans by skin color is arbitrary, might get some aspect but not all variation ○ Clinal distributi atterned distributi cross a geographical gradient ■ One area has most then as you get away from it there is gradual change ■ Continuous, no break ○ Poor concordance between different traits ■ Each trait is spread throughout globe in different w one population won’t always have particular trai o can’t stereotype) ○ Biology of skin color: ■ Outside layer is epidermis made out o eratinocytes (largest number, made in bottom of epidermis and move outward, p roduce keratin which gives water protection) and melanocytes (not as many, creates pigment melanin) a. Melanin is one factor that gives pigment, gets deposited throughout epidermis ■ Color of skin depend on: a. Hemoglobin: w hat allows blood cells to transfer oxyg ives red tint b. Keratin: different in amount of kerat ives yellow tint c. Melanin: M AJOR DETERMINANT, d ark pigment so the more melanin that is produced the darker it is, the less melanin present the more the other pigments are visible i. Number of melanocytes is about same, b ut amount of melanin produced and deposited in keratinocytes ii. POLYGENIC TRAIT, d ark: lots of production of melanin, light: less melanin produced ■ Skin color follows clinal distribu arker when closer to Equator and lighter when further from Equato looking at indigenous populations) ■ UV radiation is higher in Equator and less in poles a. Damage DNA in cells b. High energy and non-visible radiation in sunlight c. Melanin absorbs UV and prevents it more damaging DNA d. Degree UV penetrates the skin is inversely proportional to melanin ■ 3 main theories of natural selection and UV: 1. Dark skin is adaptation to skin damage and skin cancer 2. Nutrient photolysis: folic acid 3. Vitamin D synthesis ■ Skin damage: a. Skin cancer seen more in light sking living in tropical areas, l ow in dark skin population b. Places like Africa and Australia are hotspots for skin cancer in immigration population ○ Natural selection for dark skin in tropical areas, dark skin is more fit ■ Nutrient photolysis: a. Chemical molecules important to metabolism are sensitive to UV radiation and ill undergo decomposition (photolysis) b. Folic acid: i mportant to central system development, DNA replication and cell division i. Deficiencies can lead to regnancy complications, neural tube effects, impaired sperm production w hich impact REPRODUCTIVE SUCCESS ii. Photosensitivity of these nutrients suggest that it is important to have rotection from the depleting effects of UV radiation c. Dark skin more fit because decreases folic acid ■ Vitamin D synthesis: a. Essential for calcium metabolism and normal bone and tooth development b. Primary source of vitamin D is synthesis in skin i. Made through interaction of UV and cholesterol-like substance ii. Dark skin requires six times as more to make vitamin D in sun c. Rickets: disease in kids caused by itamin D deficiency that causes impaired mineralization of developing bones and teeth i. Negatively impacts reproductive success and drive selection for light skin far from Equator to guard for vitamin D deficiency ■ MORE MELANIN FOR NEAR EQUATOR AND LESS FAR FROM IT a. Humans originated in Africa so were probably dark skin, only recently have humans began to live in high latitude areas b. Only recently have populations in northern latitudes evolved lighter skin color ue to relaxed selection of dark skin and direct selection to absorb more UV to make vitamin D ○ Sickle Cell Anemia: ■ Crescent shape of red blood cell ■ Caused by POINT MUTATION (single letter swap out for another) in ancestor’s gamete in hemoglobin gene which allows blood to transfer oxygen and influences shape of red blood cell ■ Individuals with sickle cell anemia have wrong red blood cell shape a. Normal red blood cell shape allows it to go through all body even small vessels but ickle cells can not go through because get stopped and PILE UP leading to blood clots b. Sickle cells also more fragile, can’t carry oxygen as well ■ HbA = normal, HbS = sickle, genotypes: HbA HbA (homozygous normal so no risk of disease), HbS HbS (homozygous sickle so have disease but can be treated with medicine, if not medicine available then disease can be decreased so n ot wanted in natural selecti bA HbS (heterozygous, incomplete dominance (codominance) so have normal and sickle cells, have little symptoms of disease) ■ Pockets in Africa, India and Middle East with lots of sickle cell anemia a. Natural selection keeps disease because it is good to be heterozygous HbA HbS b. Areas with high malaria are same with those with more sickle c. Heterozygous have resistance to malaria so HETEROZYGOUS IS MORE FIT THAN BOTH HOMOZYGOUS DUE TO MALARIA ■ Balance polymorphism: s table polymorphism, natural selection prevents any alternative alleles from being fixed or disappearing a. Heterozygous advantage: more fit to be heterozygous ○ Lactose intolerance: ■ ALL MAMMALS DRINK MILK IN INFANCY a. Lactose found in milk and made of glucose and galactose so mammals have lactase to break it down b. Most mammals lose ability to produce lactase after weaning ■ Adult lactose intolerance is NORMAL in mammals a. When you are intolerant you are unable to break down lactose so bacteria break it down which leads to gas ■ LCT*P (dominant) = lactose persistence, LCT*R (recessive) = lactose intolerant ■ Lactose tolerance evolved by recent natural selection favoring lactase persistent in CULTURES WHERE MILK IS PART OF WAY OF LIFE a. In Africa: fulani have 22% because historically depended on cattle so good to persistence, not seen in Bantu ■ Adult lactase persistence aused by mutation resulting in permanent production of lactase a. Neutral in no dairy cultural but beneficial in dairy cultures so common ○ Body size and shape: ■ Bergmann's Rule: individuals in colder habitats tend to have larger body size a. More volume so less heat lost through body surface b. BIG IN COLD, SMALL IN HOT c. Seen in bear size: tropical bears are smaller, American brown bears are a little bigger, grizzlies are bigger than that and polar bears in Arctic are biggest ■ Allen’s Rule xtremities tend to be longer in warmer habi ecause serve to dissipate heat through them a. Antelope Jackrabbit has longer legs and ears because warmer, Arctic hare have smaller ears because cold ■ BOTH RULES APPLY TO HUMANS a. Those in Arctics have longer body but short extremities, those near Equator have shorter body and longer extremities (African Dinka v. Inuit) ○ High Altitude Adaptations: ■ Not less oxygen percentage just that air is less dense so molecules are further apar o less molecules come in during a single breath ■ When not adapted you experience a ltitude sickness ■ Population in high altitude for generations have different adaptations a. Andean Altiplano: more hemoglobin, different lung size and shape to have more lung capacity b. Tibetan Plateau: low hemoglobin, higher respiration rate and increased blood flow c. Different adaptations between two populations but all help with the higher latitude ○ Adaptations not climatization ■ If you are not from there you won’t have the adaptations
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