Exam 1 Study Notes

• Study notes for Exam 1

Exam 1 Format

• Exam 1 is on Tuesday, March 11th
• The exam is during the 50-minute class period
• There are 40 questions
• Questions are multiple choice and true/false
• Pen is preferred when bubbling in answers
• Blue or black pens are recommended, avoid crazy colored pens

Exam 1 Rules

• No phones or headphones/airpods/earbuds are allowed during the exam
• If you are seen with one, your test will be taken and graded as is
• If you are caught cheating, you will receive a zero and be reported to the Academic Integrity office
• Don't cheat

Tips for Exam 1

• Read through the entire exam and answer questions you are confident about first
• Go back and answer the trickier questions

Human Descent

• Humans did not descend from Chimpanzees
• Humans and chimpanzees evolved from a human-chimp last common ancestor
• Evolution of genus Australopithecine led to genus Homo and humans (homo sapiens)
• Evolution of genus pan led to chimpanzees (Pan troglodytes)

What is a gene?

• A gene is a sequence of DNA bases that specifies the order of amino acids in a protein
• Know the Structure, Function and the difference from RNA
• Genetic variation is produced via mutation, random assortment (occurs via sexual reproduction), and recombination (crossing over)
• Humans commonly have two copies of most genes
• Males with XY chromosomes have only one copy of genes found on the X chromosome and one copy of the genes found on the Y chromosome

Cell Types

• Somatic cells include all body cells and have direct cell activity
• Somatic cells are diploid; human somatic cells contain 46 chromosomes
• Gametes are reproductive cells; males have sperm and females have eggs
• Females gametes provide cytoplasm, including the mitochondria
• Gametes transmit genetic information
• Gametes are haploid; human gametes contain 23 chromosomes
• Members of a pair of chromosomes include one chromosome from a male parent, and its partner from a female parent
• A gene locus is the location for a specific gene on a specific type of chromosome
• Alleles influence the same characteristic, their DNA varies slightly, so they produce somewhat different expressions of the same trait

Simple Vs. Complex Traits

• Simple traits (aka Mendelian traits) are traits whose variations are controlled by different versions of a single gene like earlobe attached or not, red/green colorblindness, dimples
• Complex traits are influenced by more than one gene or environmental factors, such as height, skin and hair color

Sex Development

• Biological sex determined by sex chromosomes, genes that control the development of the gonads and genes that control sex steroid receptors

Mendelian Terms

• Dominance is a a trait expressed in the presence of a different allele
• Recessive is a trait not expressed in the presence of a dominant trait
• Homozygous means having the same allele at the same locus on both chromosomes (TT, tt)
• Heterozygous means having different alleles at the same locus (Tt)

ABO Blood Groups

• There are 3 alleles, A B and O
• Codominance
• Type A: AA, AO and Antigen A present
• Type B: BB, BO and Antigen B present
• Type AB: AB and both Antigen A and B present
• Type 0: OO

Human Genome Project

• Humans have fewer genes than previously thought
• Most human DNA consists of non-coding sequences
• Most of the human traits are complex

Epigenetics

• The study of chemical modifications to DNA associated with changes in the way genes are expressed
• Focuses on how variation arises despite fundamentally similar genetics
• Epigenetic marks are features not directly governed by the genetic code that are found on a DNA molecule and regulate gene expression
• This includes:
• DNA Methylation: methyl group attached to DNA molecule and ends up suppressing enhancing chemical components of DNA
• Histone Modifications: Impacts the ease with which DNA unwinds – sensitive to environmental conditions
• MicroRNA: tiny strands of RNA binds to section of DNA and makes to difficult to use DNA as a template

Regulatory Genes

• Regulatory genes act solely to control the expression of other genes, like homeobox (Hox genes)
• Regulatory genes encode homeodomain protein products, which are transcription factors
• Transcription factors influence which genes get transcribed
• Regulatory genes play an important role in embryonic anatomical development and are highly conserved
• These regulatory genes control where/how structures grow during development

Evolution

• Evolution describes a change in the gene frequencies of a population over time

Modern Synthesis of Evolution

• Includes Malthusian competition (geometric population, limited resources) 19th century
• Variation leads to Genetic Variation (breeds, races, subspecies)
• Natural Selection ("survival of the fittest’) early 20th century
• Mutation (small changes in individual characteristics)
• Mendelian inheritance of which gives 2 copies of each gene, 1 from each parent

Foundational Concepts and Ideas

• Include species concept and taxonomy, decent from a common ancestor, lamarckism, extinction, that the earth is old, and there is competition for resources

Forces of evolution: Natural selection

• There is biological variation in all species
• There are more offspring than resources
• Competition
• Greater fitness = survive+ reproduce
• The environment determines what is beneficial
• Traits are inherited and passed on
• Variations accumulate in a population
• Geographical isolation contributes to new species

Forces of Evolution: Natural Selection

• Directional selection selects for one extreme against the other; average condition moves in a direction
• Stabilizing selection selects against both extremes; average condition remains the same, but range of variation decreases
• Disruptive selection selects for the extremes and against the mean; bimodal

Forces of Evolution: Mutation

• Generates brand new genetic variation and increases genetic diversity
• Most mutations are found in DNA regions that don't have a function (non-coding regions)
• This shows an original sequence of TACG and a point mutation of TACG to TGGG

Forces of Evolution: Genetic Drift

• An example of neutral evolution
• The founder effect decreases genetic diversity
• This shows a mother population undergoing founder effect to result in a new population.

Forces of Evolution: Gene Flow

• An example of neutral evolution
• Increases genetic variation in the population
• Gene flow is the exchange of genes between populations.

Vertebrate Evolutionary History

• Mesozoic = continents separated, Reptiles dominant land vertebrates – “Age of dinosaurs”
• Cenozoic = “Age of Mammals”, Birds and mammals replaced reptiles
• Chicxulub impact occurred 66 million years ago, 50-70% of all living species go extinct
• Mammalian adaptive radiation = Diversification of a group of organisms into forms filling different ecological niches, burst of diversity

Taxonomy

• From the animalia kingdom to the kingdom of apes and humans.

Homologies

• Homologies are similarities between organisms based on descent from a common ancestor

Analogies

• Analogies are similarities between organisms based on common function – no assumed common evolutionary descent.
• Examples are the Kinkajou, Capuchin monkey, Tamdua Spider Monkey, Coendou

Primitive vs. Derived traits

• Primitive traits are inherited from distant ancestor
• Derived is newly evolved and unique to a certain group/
• EX for Primates is listed below
• primitive is shared with non-primate mammals, like Body hair, Mammary glands, Heterodonty, and Endothermy
• derived traits are only found with Primates: like, Grasping hands/feet (opposable thumbs/toes), Tactile pads on fingers, Long gestational period, Nails, Relatively big brain, Forward facing eyes and Post orbital bar are all traits

Factors Affecting Social Structure

• Diet
• Related to body size and BMR
• Distribution of Resources
• Leaves are abundant and dense which equals large groups
• Insects/ fruits are scattered which equals solitary/pairs

Predation

• Factors are body size, predator and social structure
• Relationships with other species
• Sympatric species: 2 or more species whose habitats overlap
• Dispersal
• Who stays and who goes
• Activity patterns
• Human activities

Functional Anatomy

• Quadrupedal is Arboreal vs terrestrial
• Vertical leapers are Long hind limbs
• Brachiation is Longer arms than legs
• Bipedal is Longer legs than arms

Human Chimp Ancestor

• Lived ~6 million years ago
• Closer to a chimp-sized brain/ body
• Had long arms and fingers and a grasping foot, and foraged in trees
• Had large canines, and are sexually dimorphic
• Was Quadrupedal
• Almost entirely ate plant foods

Genus Australopithecus

• Adaptive radiation of early hominins
• Lived between 1-4 mya
• Small bodied (64-100 lbs)
• Small brained (340-500 cc)
• Larger teeth (ancestral)
• Thick enamel (ancestral)
• Bipedal adaptations

Homo Habilis

• ~ 2.4 mya
• Had reduced facial size and moderate-small browridges
• Encephalization of 630 cc: FIRST ONE LARGER THAN A CHIMP
• Possibly the first hominins to use stone tools

Homo Erectus

• Had a body weight >100 lbs; average height ~ 5' 6"
• Was Encephalization – cranial capacity 750-1250cc and overlaps with human capacity

Human Evolution

• Anatomically Modern Humans Evolved in Africa 300-200 kya

Encephalization Quotient (EQ)

• EQ is a measure that describes how the observed brain size compares to the body mass

Human Adaptation

• How do humans adapt to the high energy cost of brain metabolism?
• High quality diet and reduced gut size
• Human newborns are altricial, and their brains grow rapidly after birth
• Human babies have a high percent body fat

Lecture 11 Question

• Which of the following should you NOT do in order to show up prepared for this exam?
• C. Leave your headphones in your ears during the exam