Anthropology Test #1

Natural selection can affect behavior (the "extended phenotype")

ex. birds of a species are born all knowing to sing the same song, even if they are born in isolation ex. beavers feel compelled to dam up a stream whenever they hear water ex. brown-headed cowbird ensures the survival of their young by laying their eggs inside of the nest of another species. If these birds refuse to care for the egg, the cowbird will often destroy the nest/the other eggs

Some traits aren't unique just to humans

ex. parenting, hunting, bipedalism. It's a mixture of various things like this that makes us human

Proteins are made up of

amino acids

rRNA (ribosomal RNA)

an organelle that contains most of the RNA in the cell and that is responsible for ribosome function

What is the basis of science?

asking testable questions The scientific method

DNA structure

DNA consists of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine - sugar = deoxyribose - phosphate - nucleic acid base - nucleotide - double stranded phosphate and sugar are on the outside, the backbone of the DNA (probably acts as protection). In the middle is the nucleic acid base, and there is a second strand with the matching bases

Natural selection

- Alleles that improve fitness become more common --> adaptive alleles increase, harmful alleles decrease. --> This is the only force that isn't random ex. in the arctic, lighter fur color helped polar bears adapt to their environment better, and darker furred bears died out Three necessary conditions for natural selection: - There must be Variation in the trait - Variation in the trait must affect Competition - The trait must be Inherited (shaped by genes) Fitness: Probability of producing surviving offspring 1. Usually measured as number of surviving offspring produced 2. Fitness is measured relative to others in the population Also defined as: changes in allele frequencies in a population due to differential reproductive success. The only force of evolution which is not random. - Natural selection works on the fit between an organism and its environment, "survival of the fittest" - But, that doesn't mean it produces 'perfect' or 'the best imaginable' solutions. It is contingent (what is available to the organism) and local (something adaptive in one environment might not be adaptive in another environment, ex. fur color).

Charles Darwin (1809-1882)

- Born from a wealthy British family - developed the first workable theory of how evolution occurs - evolution through natural selection - He goes on the Beagle for a 5 year expedition to be the ship's naturalist - He read Lyell's book at this time and learned about how the Earth is incredibly old --> begins to question the idea of separate creations (why would god take the time to make so many finches that are so similar to each other?) --> fossil animals very similar to living animals --> Galapagos Islands have different animals on different islands - During this voyage, Darwin gets on board with the evolutionary view - Darwin did experiments with artificial selection --> How did selection occur in nature? He proposes that if you agree with these three laws, natural selection exists: - Limited resources/competition - Variation (all living things vary, even if it's just slightly) - Inheritance (parents pass something on to offspring so that kids look like their parents) ex. there is variation in giraffe neck length, and the ones with the longest necks get the most food and have the most offspring --> their offspring have longer necks like them

Altruism in humans

- Cost is low because of technological advancement and ease of overproducing resources? - Humans evolved in closely related societies where sharing was extensive, opportunities for reciprocity - Sharing behaviors have been co-opted in more recent non-related societies

Ancient Egypt 3100 BC - 300 BC

- Feats of engineering (pyramids) - Geometry - Astronomy - Paper greek and roman empires also had technological advances, but after the fall of the roman empire these advances moved to the islamic world

Mendelian Genetics

- Gregor Mendel (1822-1884), he was a priest (they did a lot of biological experiments) - Principles of inheritance - Pea plants (ex. wrinkly vs smooth, color) --> he discovers that some traits are dominant because when he breeds wrinkly and smooth peas, all the peas are smooth rather than half and half, and in the following generation of the reproduction of these smooth peas, there reappear wrinkly peas --> what's actually happening here is your homologous chromosomes have different alleles which code for different proteins and lead to different phenotypes ----> alleles are alternative versions of the same gene found on homologous chromosomes ----> genes occur at specific loci on the chromosome Mendel's work led to three key principles of trait inheritance: - Dominance and recessiveness - The law of segregation - The law of independent assortment

Steps of the Scientific Method

- Making an observation about something - Make an informed guess about why it happens (hypothesis) - Design an experiment to test your hypothesis - Run your experiment - Analyze the data - Make a conclusion Experiments need to be done over and over before the results are taken as fact. When something has been consistently proven, it becomes a 'law'. Times when people weren't actually testing theories tended to be darker times (i.e. salem witch trials had no actual scientific tests to determine if someone was a 'witch')

Meiosis

- Meiosis is the production of sex cells / gametes - Meiosis has two rounds of cell division, whereas mitosis only has one Stages of Meiosis: Prophase I, Metaphase I, Anaphase I, Telophase I --> Prophase II, Metaphase II, Anaphase II, Telophase II - The end result is four haploid cells (23 chromosomes), whereas mitosis produces two diploid cells (46 chromosomes) Meiosis also has extra steps: crossing over and recombination + random assortment

Mitosis

- Mitosis is the process of division of somatic cells - Produces 2 identical daughter cells -Mitosis is important because... --> Growth and development from one cell to many --> Cell renewal and repair - Mitosis has four stages: Prophase, Metaphase, Anaphase, and Telophase Prophase: chromosomes duplicate just before this stage (so now there are 92), and during prophase they are condensed in the cell Metaphase: The chromosomes line up in the center of the cell Anaphase: spindle fibers attach to the center of these duplicating chromosomes and start pulling them apart Telophase: two new cellular membranes start to form as it prepares to split apart, and each membrane has half of the chromosomes (both end with 46) --> in cytokinesis they split completely into two cells

History of scientific thought: 16th & 17th century

- Scientific revolution - Geology - Astronomy - Heliocentric vs Geocentric universe - Discoveries / Scientific tools This time is thought of as the discovery of science, but other non-European countries had been working on science and math for centuries Middle ages in Europe had seen no use of a scientific method The 14th-17th century renaissance is really a rebirth where Europeans used the knowledge gained by other societies and ancient rome to start developing things again

James Hutton (1726-1797)

- Scottish geologist - Studied variations in landforms (i.e. rocks) by looking at current mechanisms. We can see these changes like erosion happening very slowly and estimate how long it must've been going on for - Canyons were cut out by rivers, etc - SLOW but continuous changes (ex. the grand canyon took 17 million years to get to this point) - The earth is old

Carl Linnaeus (1707-1778)

- Swedish naturalist - First formal classifications of species - Taxonomy: science of describing and classifying living organisms - He comes up with the definition of Species: group of populations whose members can interbreed - He created a hierarchy of all known living species - He published this hierarchy in his book, Systema Naturae - Binomial nomenclature --> Genus species --> e.g. Homo sapiens, Pan troglodytes (it's italicized, capitalize the genus but not the species) - This improves scientific communication about species Linneaus still believed in the fixity of species (that species wouldn't go extinct/change much over time), but conceded that change might be possible He believed that humans are the apex of evolution: Scala naturae - like a ladder and we are at the top - organisms can be ranked from less evolved to most - Means nature's ladder - This theory is incorrect

Changes in the number of chromosomes (Genome Level)

- These result in ploidy changes - Aneuploidy --> Plus or minus one or a few chromosomes n = haploid (gametes) 2n = diploid (normal individual) 3n or more = polyploidy

Islamic World 7th C- 15th C CE

- Trigonometry - Calculus - Physics - Chemistry - Biology - Evolution Scientific method was also first developed during this time period by Ibn al-Haytham

Charles Lyell (1797-1875)

- Uniformitarianism (this is what he calls Hutton's idea --> uniform changes over time) - processes operating in the past are the same as those operating today - earth was produced by constant forces as currently observable (wind, rain, erosion) acting slowly over a long period of time - The earth is old!! - He incorporated Hutton's ideas into theory How does change occur? Erasmus Darwin (1731-1802) --> Darwin's grandfather, believed in evolution. --> Charles Darwin didn't come up with evolution, he came up with how evolution works

ABO Blood type

- a simple mendelian trait - A, B, and O alleles. Each person has two. Possible genotypes: AA, AB, AO, BB, BO, OO Possible phenotypes: (A and B are dominant (co-dominance) and O is recessive) A, B, AB, O ex. dad has type A blood, mom has type B blood, baby has type O blood. Can he be the father? Dad possible genotypes: AA, AO Mom possible genotypes: BB, BO If he had AO and she had BO, there would be a 1/4 chance of the baby having type O blood ex. dad has type O blood, mom has type AB, baby has type O blood. Can they be the parents. Dad possible genotype: OO Mom possible genotype: AB There is a 50/50 chance of their child being either type A or B, but it's impossible for them to have a type O baby. Ex. mom had AB, dad has AB. Phenotype frequency: A:B:AB:O --> 1:1:2:0 (Genotype frequency is the same, but AA:BB:AB:OO)

George Cuvier (1769-1832)

- catastrophism --> he thinks that a series of catastrophes have periodically destroyed most life on earth (by god) - areas of destruction restocked with animals/plants from unaffected areas - life recorded in strata of rocks - succession of fossil species - Each unique assemblage - Speculated about catastrophes Catastrophism: the appearance of new species is explained by migration and repopulation

random assortment (meiosis)

- each chromosome is randomly sorted into a gamete with other chromosomes; = even more variation is produced in gametes The chromosomes, which have already been mixed up through recombination, are now distributed randomly throughout the four gamete cells

genetic code and protein synthesis

- genes (DNA) are a code for protein production - DNA base sequence determines amino acid sequence in proteins

Species

- groups of organisms that can reproduce successfully with each other and are reproductively isolated from other such groups - these are multiple isolating mechanisms (geographic, temporal, behavioral, mechanical, genetic, post reproductive) geographic - you're not in the same place, can't reproduce temporal - they are out and about at different times, i.e. one species is awake during the day and the other is awake at night behavioral - mating rituals, songs, etc only attract other members of the same species mechanical - the physical reproductive parts don't fit together genetic - different number of chromosomes or genetic profiles aren't complementary post reproductive - these species can have a child but their child is sterile/can't reproduce themselves

Genotype vs. Phenotype

-Genotype : Collection of alleles (what's in your genes) -Phenotype : Physical expression of alleles (external appearance)

A short history of modern genetics

1953 - DNA structure discovered by Watson, Crick, and Franklin 1972 - First gene sequenced 1976 - First genome sequenced (virus) 1987 - First auto-sequencer late 90s/early 2000s - high through-put sequencing, sequencing becomes cheaper 2001 - human genome published

The human genome

3 billion base pairs Each person carries two sets, so 6 billion bases - 20,000 protein-coding genes. far more regulatory genes (to turn on/off the protein coding) We don't know what the purpose of a lot of these bases is - the function of many genes is unknown (at least 42%) - Many parts of the Genome are under selection - humans are still evolving (balancing selection -> basically the same for everyone. directional selection -> we can see that these genes have changes and are moving toward a certain direction) Humans are still evolving, and we can watch it happen When companies like 23&me sequence your genome, they aren't doing the whole thing but just parts of your genes

Embryo

46 chromosomes (23 from each parent) mtDNA from mother

Genetic drift

A change in the allele frequency of a population as a result of chance events rather than natural selection. - Alleles lost through random chance --> decreased allele diversity - changes in allele frequencies produced by random factors --> E.g. founder effect, population bottleneck

Punnett Square

A chart that shows all the possible combinations of alleles that can result from a genetic cross ex. Dad has TT alleles and mom has tt, all kids will be Tt (heterozygous). phenotype ratio= 4:0, genotype ratio = 0:4:0 phenotype ratio = dominant:recessive, genotype ratio = homozygous dominant: heterozygous: homozygous recessive example 2. Dad has Tt and mom has Tt. phenotype ratio = 3:1, genotype ratio = 1:2:1

DNA

A complex molecule containing the genetic information that makes up the chromosomes. Completely unique from one person to the next. Deoxyribonucleic acid - DNA can be found in the nucleus (nuclear DNA, 46 chromosomes) and mitochondria (mitochondrial DNA / mtDNA) --> mitochondrial DNA comes from an organism that was absorbed by another organism (a bigger cell), with which it formed a symbiotic relationship (produced lots of energy for the bigger cell --> this is the origin of eukaryotes mitochondria is inside an egg and on the tail of a sperm (which isn't absorbed), so your mtDNA only comes from your mom - nuclear DNA has lineage of both parents, mtDNA only has the lineage of female side

Sexual selection

A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates. - Natural selection acts on traits that affect mating success - Fundamental asymmetry of the sexes --> reproductive investment: females invest more than males (gestation period, raising the offspring, etc), so males of some species have to work harder to seem an attractive mate --> Females are 'choosy', invested in the quality of their offspring --> males compete, invested in the quantity of their offspring

population bottleneck

A period during which only a few individuals of a normally large population survive. ex. disease, natural disasters, being hunted - since the surviving population is smaller than the normal population was, they will automatically have less genetic diversity than the bigger group

Gene

A segment of DNA on a chromosome that codes for a specific trait "A section of the chromosome that makes proteins or regulates other genes"

Codons

A three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code.

Founder effect

A type of genetic drift where genetic diversity is lost when small groups break away from large groups (ex. some members break into their own group but none of them have one of the alleles of the main group --> this new group suddenly has one allele less in the population than they did before) ex. Europeans are small groups that broke away from a larger group in Africa --> this caused them to have less genetic diversity. The continent of Africa still has the greatest genetic variation

A gene is a section of ___ that makes a protein or regulates the activity of other genes. A) DNA, B) RNA, C) Mitochondria, D) cell

A) DNA

DNA bases (4 nucleic acid bases)

Adenine, Thymine, Guanine, Cytosine (ATGC) A bonds with T, and G bonds with C The sequence of the bases determines the DNA's function Mutations can occur and change the sequence of the bases

___ are different versions of genes.

Alleles

Interaction types

Altruism, Spite, Cooperation, Selfishness Selfishness is most common, and cooperation is also somewhat common. Altruism and spite are least common in nature. Altruism might only be present in humans inclusive fitness = cooperation, because it's also benefitting yourself reciprocity - type of cooperation, 'paid later' selfishness - natural selection is about promoting your genetic lineage over all others Humans are cooperative in part because adults overproduce food needed for consumption and have enough for the young and elderly to share. Humans have become highly domesticated in regards to sharing and cooperating with others ---> Food sharing leads to shorter inter-birth intervals

Genotype

An organism's genetic makeup, or allele combinations. The chromosomes you have, your actual DNA. ex. your genotype might be that one of your homologous chromosomes has a green eye color allele and the other has a blue eye color allele. The phenotype would be green because blue is dominant, but the genotype is made up of both the blue and green alleles. recessive alleles have to have two copies of the allele to express that, dominant alleles only have to occur once for that to be expressed Genotype names: - if you have two different alleles, you're heterozygous - if you have two dominant alleles, you're homozygous dominant - if you have two recessive alleles, you're homozygous recessive

Phenotype

An organism's physical appearance, or visible traits. ex. eye color: genotype= blue allele, brown allele; phenotype = brown --> heterozygous

Behavioral evolution

Belyaev Fox Experiment - Began in the 1950s in Russia - Starts with a population of wild foxes and tests their reactions to humans --> those which are aggressive are killed, but those that are friendly are bred --> after only a few generations, the foxes are super friendly and playful --> the change which led to friendliness actually led to changes in many traits (floppy ears, short tail, curly tail, etc) -----> this is an example of pleiotropy where one gene affects many traits --> The foxes were also retaining juvenile features into adulthood, they looked like puppies -----> This is called neotony (adults retain juvenile features)

tRNA is responsible for ___. A. splicing out introns to make mature mRNA. B. copying the DNA and transporting to the cytoplasm to make proteins C. bonding to codons and bringing amino acids to make proteins

C

___ are long strands of DNA. A normal human cell has 46 of them, 23 from the biological father and 23 from the biological mother.

Chromosomes

homologous chromosomes

Chromosomes that have the same sequence of genes and the same structure (in the same places) Since one is from mom and one is from dad, the information in them is a little different though (different alleles)

sexual dimorphism

Differences in physical characteristics between males and females of the same species. --> part of sexual selection --> males tend to be larger and in a lot of species they fight the other males to get access to mates --> quite unusual to have a species where females are competing for male mates

Dominant and recessive alleles

Dominant alleles are always expressed - Y = dominant allele Recessive alleles are masked whenever they are paired with a dominant allele - y = recessive allele ex. YY = yellow pea (homozygous dominant), Yy = yellow (heterozygous), yy = green (homozygous recessive) --> these are the 3 possible genotypes

law of independent assortment

Each member of a pair of homologous chromosomes separates independently of the members of other pairs so the results are random (crossing over & recombination) - Genes for different traits are inherited separately ex. If you inherit a gene for brown eyes this does not mean you will also inherit genes for O blood type

Thomas Robert Malthus (1766-1834)

Economist - principle of population (his book) - he finds that populations grow exponentially, and food production increases linearly --> populations increase faster than food supply - there is competition for survival even in a modern society

Niche

Full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions The specific way in which a species procured energy from its environment Compared to other species, humans have an extremely broad niche Niche size is expanded due to culture

4 main subfields of biological anthropology

Genetics, fossils, primatology, human biology and variation

Complex traits

Genotype & Environment --> phenotype - Norm of Reaction - Pleiotropy

Predicting interactions

Hamilton's rule C/B < r C = cost to giver, B = benefit to recipient r = relatedness between individuals Cost is high, benefit is low, relatedness ~0 = exchange unlikely to happen C is low, B is high, R=1, cooperation likely C is low, B is high, R-0, opportunity for reciprocity

Jean Baptist Lamarck (1744-1829)

He came up with one possible mechanism for species change - French naturalist - 'inheritance of acquired characteristics' - ex. giraffes constantly stretching their necks up will grow longer necks and pass that longer neck to their offspring (only takes one generation) His theory is obviously wrong, but he did come up with an important idea: adaptations - a feature of an organism that helps it survive in its environment - He was the first to suggest that inheritance plays a role in acquired characteristics --> /something/ is inherited, but he didn't know about genes and couldn't guess what it was making the change

Chromosome numbers

Humans typically have 23 pairs of chromosomes - 46 in total - For each pair, one chromosome comes from the mother and one from the father - chromosomes 1-22 are called autosomes (controls physical characteristics except sex), while the 23rd pair is called sex chromosomes (X, Y --> sex determination) Females = XX, Males = XY - Karyotype: all the chromosomes of an individual - Haploid: a cell with one chromosome set (n = 23 --> human haploid number) - Diploid: a cell with two chromosome sets (2n = 46 --> human diploid number) variation in number of chromosomes is natural and not entirely uncommon Having more chromosomes doesn't mean an organism is more complex (ex. tobacco has more chromosomes than humans)

Mutation

If a really tall mutation was added in, that would shift the population to become taller. The frequency of tall alleles would increase. - New alleles arise through changes in DNA --> this produces variation --> this is the only way you can get entirely novel alleles - mutations have to occur in sex cells for them to be heritable / passed on to children --> most mutations are either harmful or neutral, though some are helpful mutation example: sickle cell anemia - this mutation affects the shape of the protein and your red blood cells. These sickled cells don't transport oxygen as well or move through your veins as well (leads to bleeding/clotting) - mutations increase allele diversity --> an advantageous mutation may spread throughout a population due to natural selection

Convergence

Independent evolution of similar traits - Similar solutions can evolve independently - Similar challenges, similar selection pressures = similar traits

Linnean Hierarchy

Kingdom, Phylum, Class, Order, Family, Genus, Species ex. Animalia, Chordata, Mammalia, Primates, Hominidae, Homo, sapiens What makes us animals is that we have to eat things for energy, chordata has to do with having a spine and a central nervous system, mammals is about mammary glands, primates have grasping hands, color vision, etc. Hominidae are great apes - big bodies, big brained, no tails.

Law of Segregation

Mendel's law that states that the pairs of homologous chromosomes separate in meiosis so that only one chromosome from each pair is present in each gamete - Each parent only gives one allele/chromosome

Simple Mendelian Traits

Mendel's rules: segregation, independent assortment, dominance

Name 2 differences between mitosis and meiosis.

Mitosis ends in 2 somatic cells, whereas meiosis ends in 4 gametes. Mitosis leads to direct copies of the original cell, whereas meiosis changes the genetic material for more variation (recombination and random assortment)

Mitosis vs. Meiosis

Mitosis: Somatic cells, produces 2 cells at the end through one division phase, cells are diploid (2n), cells are genetically identical Meiosis: Sex cells (gametes), produces 4 cells at the end through two division phases, cells are haploid (n), cells are not genetically identical --> recombination, random assortment We want variation in sex cells but not in somatic cells

Gene flow

Movement of alleles into or out of a population due to the migration of individuals to or from the population - alleles exchanged between populations --> populations which originally weren't in contact with each other meeting and interbreeding, which adds new variation into a population --> unique mutations which have popped up in either population can spread between the two groups through interbreeding Gene flow INCREASES allele diversity - exchange of genes between populations - migration with interbreeding

Stabilizing selection

Natural selection that favors intermediate variants by acting against extreme phenotypes (average trait is favored) ex. clutch size - if a bird has two few eggs it's not reproducing enough, but if it has too many it can't take care of them all. Therefore, there is an average amount which is most adaptive. ex. human birth weight - if you're born too small you might not survive, but if you're too big your mom might not survive

Introns

Noncoding segments of nucleic acid that lie between coding sequences. (not involved in making the protein)

Spandrels

Not all traits are adaptive - adaptation must be proven, not assumed Spandrels are neutral traits that are by-products of selection for something else - ex. belly button. alone, it is neutral, but it is also the byproduct of a large umbilical cord - ex. chins are also neutral and are just a byproduct of reduced face size

Proteins

Nutrients the body uses to build and maintain its cells and tissues. Proteins are the building blocks of your body. Genes make these proteins or regulate other genes (turn them on or off) Alleles are different version of a gene

Primatologist

Person who studies living primates - our closest living relatives: behaviors, ecology, and cognition These studies take place in the tropics like south america and central africa Time travel: help us to understand the environmental forces that shape primate behavior and ecology, which also shaped past human evolution An example of a question that primatologists have worked to answer is why do humans have the largest brain to body size/why do other great apes have such large brains? --> Learning and remembering the locations of highly nutritious fruit may have increased brain size, increased knowledge. It takes a lot of energy to feed a huge brain which is why many other species don't also have huge brains Fruit eaters tend to have larger brains than herbivores

Changing views of evolution

Pre-evolutionary view: -earth not very old (<10,000 years) -species fixed -each species was separately created (by God) - Didn't usually believe in extinction Evolutionary view: - Earth is old (4.5 billion years) -species can change - species evolved from other species Change occurs when: - europeans travel around the world and see huge variation in organisms. - Also the revolution of anatomy, realizing that many animals have similar bone structures (i.e. humans, cats, and whales all have similar arm structures) - study of geology (history of the earth) shows that the earth is much older than earlier estimates. In the 18th century they discovered that different layers of earth contained different fossils --> more recent fossils are more similar to living animals.

Translation

Process by which mRNA is decoded and a protein is produced - occurs in the cytoplasm --> tRNA (transfer RNA) attaches to mature mRNA to make amino acids, which come together to make a protein

Antibodies

Proteins that attach to antigens (proteins on the outside of viruses), keeping them from harming the body A person with a certain blood type has an antigen that isn't complimentary to the antibodies in their blood, so the antibodies don't recognize their blood as a foreign object - Type O people have no antigens on the outside of their blood cells, but they have all the antibodies. They are universal donors because their lack of antigens means that no antibodies in other people's blood will see it as a foreign invader - AB people are universal recipients because their blood has all the antigens on it but they make none of the antibodies

Anthropology - four sub-disciplines

Social, or cultural anthropology Linguistic anthropology Archeology Biological anthropology

Two basic cell types

Somatic cells (46 chromosomes) --> tissue cells --> almost any kind of cell in your body Gametes (23 chromosomes) --> sex cells (eggs or sperm) Types of gametes: - ova (sing. ovum; egg cells) - female gametes develop from precursor cells in the ovaries (a woman produces all of her eggs before she is born) - sperm cells - male gametes that develop from precursor cells in the testes (males continuously produce sperm)

Cultural anthropology

Study of all aspects of human cultural and social behavior diet, traditions, kinship, family structure, race, gender, etc

Population genetics

Study of allele frequency distribution and change under the influence of evolutionary processes. - description of genetic makeup of a population - Hardy-Weinberg law - phenotype frequency = % of people with a particular phenotype - genotype frequency = % of people with a particular genotype - allele frequency = % of allele types in a population (this is the one you really need to study to prove evolution has occurred)

Neutral Theory

The hypothesis that much evolutionary change in genes and proteins has no effect on fitness and therefore is not influenced by Darwinian natural selection. mutations, genetic drift & gene flow "This neutral theory claims that the overwhelming majority of evolutionary change at the molecular level is not caused by selection acting on advantageous mutants, but by random fixation of selectively neutral or very nearly neutral mutants through the cumulative effect of sampling drift (due to finite population number) under continued input of new mutations"

gene therapy

The insertion of working copies of a gene into the cells of a person with a genetic disorder in an attempt to correct the disorder There are ethical issues surrounding gene therapy, and we don't know how it'll affect everyone, so it doesn't happen that much anymore --> ethics ex. who decides which traits are normal and which constitute an unwanted disability/disorder

DNA replication

The process in which DNA makes a duplicate copy of itself. - The chromosome uncoils/unzips, and the bases are filled in with complementary pairs, so there are now two separate DNA strands/chromosomes

norm of reaction

The range of phenotypes produced by a single genotype, due to environmental influences. - normal range expected by the gene x environment (bell curve shape) "The range of possible expressions of the phenotype. Relationship between genotype and environment in shaping the phenotype" ex. norm of reaction for height is somewhere around 3 feet to 8 feet

Biological Anthropology

The study of human biology and behavior within an evolutionary framework evolution - how living things change over time, not necessarily inherently positive or negative

Number of Living animal species currently known

Total: 1,032,000 Most of these are bugs/arachnids There are about 4,000 species of mammals

vestigial traits

Traits that were useful in ancestors that are inherited today, but that have lost their original use. - Neutral, left-over traits that were adaptive in ancestral species - ex. grasping reflex in babies helped when we were animals who had to grab onto their mothers from childhood, because older species couldn't carry their babies - ex. whales have little vestigial leg bones inside their bodies because their ancestors had legs

Primates are mammals. What makes us mammals?

We have mammary glands & produce milk We are warm blooded, and have fur/hair We are still evolving over time

Biologically, what are humans?

Widespread species known as homo sapiens (besides birds, most other species are more regional than humans, we're all over) For a species without a significant amount of genetic diversity, we have a heck of a lot of cultural diversity Of the apes, we're most closely related to chimpanzees What makes us primates/great apes is that we don't have a tail. We still have a tailbone, but no outward tail. biological aspects of humans include behavior (ex. crying, wearing clothes), ecology (what kind of habitats do humans live in?), genetics, anatomy (bipedal)

How are traits determined?

With simple traits, your genotype = your phenotype. (ex. blood type) With complex traits, your genotype x your environment = phenotype (this is how most traits work, ex. height, weight, intelligence) --> often more than one gene affects a trait (there are 200 known genes that affect height) --> environment has an impact. Diet, disease, temperature, light exposure, training, etc. Internal environment (i.e. sex hormones) also play a role. These different aspects come together to make thousands of possible phenotypes. Multiple genes affecting the trait and multiple environments affecting it as well add up to a lot of possible combination outcomes. Most people fall in an average phenotype expression range. Ex. height - the average height may be 5'8 and as you move further away (ex. 5'0 and 6'4) fewer people fall into those categories - Complex traits usually have a 'bell curve' with few individuals at the extremes, most in the middle ---> this is called the norm of reaction

Crossing over

a process of recombination where homologous chromosomes overlap and exchange DNA; = more variation in chromosomes Happens when they're lined up down the center of the cell (metaphase) The chromosomes swap DNA Variation is a good thing in terms of biology - if something happens (ex. temperature rise) that will kill a member of the population and all members have the exact same DNA, they will all die. Variation gives species a better chance to survive changes sexual reproduction pros are that it provides variation, but a con is that it requires a mate and takes longer females tend to be choosier about their mates because they have fewer chances to reproduce than males The top thing females choose for in male mates is novelty, because novelty usually means more variation Humans go through menopause because of the genetic need to care for grandkids to assure the continuation of the lineage

Chromosome

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes. - Long string of DNA coiled into a dense thick rod - DNA is packaged into chromosomes

Evolution

change in frequency of alleles in a population over time (generations) - usually, current traits are pushed or pulled --> truly new traits are rare (ex. frogs, whales, and humans have very different looking arms, and yet the structure is actually quite similar) ----> Homology: similarity due to a common ancestor

Microevolution

changes over a short period of time (less than about 50,000 years) to produce variation within a species

Translation occurs in the ___, whereas transcription occurs in the ___.

cytoplasm (ribosome), nucleus

Alfred Russell Wallace (1823-1913)

independently developed a theory of evolution by natural selection. By this point, Darwin had been writing his book about natural selection for 30 years. He agreed to include Alfred Wallace in the publishing of the idea, and he supported Wallace for the rest of his life. However, Wallace was poor and not focused on as much, and the idea is almost fully credited to Darwin. Neither of them understood what it was that was passing from parent to offspring, and DNA wasn't discovered until the 1950s.

Macroevolution

large-scale evolutionary changes that take place over long periods of time (greater than 50,000 years) to produce new species, genera, families, etc - Scales of evolution - Species - Speciation - Principles of classification

Forces of evolution

mutation, gene flow, genetic drift, natural selection Natural selection was the first discovered force, so we fixate on it most. The rest weren't understood until we knew what DNA was --> much later.

antagonistic pleiotropy

occurs when a mutation with beneficial effects for one trait also causes detrimental effects on other traits ex. aging. Aging had to appear at some point, it wasn't something that always existed. However, if a gene that causes you to self-destruct at a certain age also causes something really beneficial, it doesn't necessarily turn out to be a bad trait and those with the traits may reproduce most 'p53 gene' directs damaged cells to stop reproducing --> stops cancer by preventing cells with DNA damage from dividing. However, this gene also stops the body from renewing cells --> aging.

Directional selection

occurs when natural selection favors one of the extreme variations of a trait ex. darwin's finches - after a drought when only large hard seeds were available, the bigger the beak a bird had the more adaptive it was ex. hominid brain size has continuously increased over time (better diet means we have more energy to develop a big brain, and the bigger our brain the better we are at foraging, which leads to a better diet. It is a cycle - positive feedback loop)

Great apes

orangutans, gorillas, chimpanzees, bonobos, and humans. Humans are the only ones who left the rain forests to live in savannahs --> part of why we developed differently

Eusocial (kin selection)

organism population in which the role of each organism is specialized and not all of the organisms will reproduce - species closely related--> opportunities for reciprocity

Hardy-Weinberg Principle

principle that allele frequencies in a population will remain constant unless one or more factors cause the frequencies to change - under certain conditions, gene (allele) frequencies do not change: a) very large population (genetic drift) b) no migration in or out (gene flow) c) all genotypes reproduce equally (natural selection) d) no mutations = if you have none of these, no change occurs (no evolution)

Sickle cell anemia is a ___ trait.

simple - this is an example of how natural selection works locally. - Sickle cell is most common in areas of Africa where malaria is most likely to be given, so even while sickle cell is harmful in some ways, it's positive because it protects against malaria - Sickle cell wouldn't be an adaptive trait in parts of the world where malaria isn't a problem (local) - AA = normal cells - AS = normal and sickled cells (enough normal cells they don't have sickle cell anemia) - SS = sickled cells (these are co-dominant traits, neither is recessive) people with AA can get malaria, people with AS don't get malaria and don't have sickle cell, and people with SS don't get malaria and do have sickle cell anemia 1:2:1 ---> Heterozygote advantage This isn't a perfect adaptation because 50% of people are still susceptible to malaria or sickle cell - Contingent on the presence of sickle cell in the population - Effective only in localized environments (beneficial in malarial zones, but negative or neutral anywhere else)

Pleitropy

the control of more than one phenotypic characteristic by a single gene - Gene affects multiple traits - ex. deafness in white cats is also linked to blue eye color. This gene appears to be pleiotropic because it's affecting coat color, eye color, and deafness

protein synthesis

the formation of proteins by using information contained in DNA and carried by mRNA. This is how we go from genotype to phenotype. ex. with brown eyes, the brown allele is producing more melanin (protein) and that overshadows the blue eye allele, so the proteins are the reason why one is dominant and one is recessive - Protein synthesis (DNA --> protein) and DNA replication (DNA splits apart to create new strands of DNA) are NOT the same thing - Protein synthesis = DNA unzips, exposes the bases on one side. Then, mRNA (messenger RNA, single stranded molecule) makes a copy of the DNA. Instead of having T (thymine), mRNA has U (uracil), so on mRNA, A matches with U -RNA only has one copy --> less protected, doesn't have a backbone, it's open and exposed. DNA may have developed to be a more protected alternative. RNA is the older molecule of the two. - A matching mRNA strand is built, using the sequence of exposed DNA bases --> The mRNA then goes off to build the protein Different sequences = different proteins - DNA bases are like letters, their sequence determines the function - Alleles are like genes with slightly different sequences, so the protein is slightly different and presents differently - mRNA needs to make copies because the DNA can't leave the nucleus --> proteins are made in the cytoplasm, so the mRNA has to travel out of the nucleus introns are removed through splicing exons (the important pieces of information) come together after the introns (not important pieces) are pulled out mature mRNA = mRNA which has had the introns removed. --> mature mRNA moves out of the nucleus and into the ribosome This is called TRANSLATION, because the RNA doesn't become a protein, but it dictates how it is made

Kin selection

the idea that behaviors that help a genetic relative are favored by natural selection - natural selection acts on traits that affect inclusive fitness --> you care and invest in the fitness of your family members because their survival is similar to the survival of your own children --> it becomes better at a certain age to invest in the genetic lineage by caring for your children's children (this is why humans go through menopause) ----> Kids with a grandma present have better newborn survival rates. inclusive fitness - the fitness of both you and those who you share your genes with

What is anthropology?

the scientific study of humans, our evolutionary origins, behavior, culture, language, and cultural remains Anthropos - Greek for humans, ology = the study of The study of what makes us human There are a lot of studies that you can argue apply to the field of anthropology Anthropology is a holistic science --> study of the whole organism, no single factor explains what it means to be human (biologist might argue that it's being bipedal, cultural anthropologist might argue those that have a concept of gender, a language, etc)

Epigenetics

the study of influences on gene expression that occur without a DNA change - proteins that can cover your genes / stop them from being read, etc

Linguistic Anthropology

the study of language and linguistic diversity in time, space, and society ex. pronunciation, humor, sentence structure, style, origins of languages and how they've changed over time, etc

Archeology

the study of the ways of past human life via material evidence Material = physical manifestations of human culture and behavior (artifacts)