ANTB14: Evolutionary Anthropology Lecture 1

Course Introduction and Evolutionary Anthropology

Course Introduction

• Course: ANTB14 Evolutionary Anthropology.
• Instructor: Dr. Kelsey Pugh. Summer 2025.
• Assigned readings for Week #1 (see Quercus):
  • Syllabus.
  • Losos, 2013. What is evolution?
  • For tutorial: Dugatkin, 2018. The silver fox domestication experiment.
  • Darwin, 1837.

A Short Story About Us

• Unifying principle of biology: all species are descended from a common ancestor and are thus related.
• Primate Evolution.
• Dinosaurs existed 70 million years ago and went extinct 65 million years ago.
• Primates evolved sometime after 65 million years ago.
• Amazing primate diversity today!

Hominoid Evolution

• Includes lesser apes (Gibbons, Siamangs) and great apes (Orangutans, Gorillas, Chimpanzees, Bonobos, Humans).
• The Human-Chimp Last Common Ancestor existed 6-7 million years ago.
• Incredible hominin diversity.
• The first hominins: bipedal walking and blunt canines appeared ~6-7 million years ago.
• The australopiths: successful group, terrestrial bipeds, but still good climbers ~4 million years ago.
• The genus Homo: early forms (2.8-2 million years ago) were similar to the australopiths but had different teeth, diet, and tool use.
  • Later, Homo erectus (2 million - ~100,000 years ago) had humanlike body proportions and a major increase in brain size.
• The origin of Homo sapiens: from a complex lineage of transitional species around 200-300,000 years ago.
• The evolution of Homo sapiens: geographically widespread and phenotypically, culturally, linguistically, and technologically diverse.

Course Goals

1. Understand the process and mechanisms of evolution and apply them to primates.
2. Read and interpret evolutionary trees.
3. Describe the place of Primates on the tree of life and use anatomical features to place different primates in their correct taxonomic group.
4. Describe the basic outline of primate evolution over the past ~65 million years, including major evolutionary developments and taxa.
5. Identify key primate species and evaluate and compare anatomy across taxa.
6. Make inferences about behavior in fossil species using the comparative method.

Common Misconceptions

1. Humans evolved from chimpanzees (or monkeys).
2. Evolution is "just a theory."
3. Evolution = Progress, and humans are more evolved than other living things.

Instructor Information

• Kelsey Pugh: Paleoanthropologist studying the fossil record for ape and human evolution.
• Preferred contact: Prof. Pugh or Dr. Pugh (she/her).
• Email: k.pugh@utoronto.ca.
• Virtual office on Zoom.
• Student Hours: Wednesdays 4-5pm, by appointment.

Course Resources

• Quercus: Syllabus, Readings, Quizzes, Tutorial handouts, Lecture slides.
• UofT email.

Communication

• Questions about course content are best posed during lectures or tutorials.
• Detailed questions during office hours.
• Short questions via email, including the course number in the subject field and using a U of T account.
• Treat emails as formal communication; expect a response within 24–48 hours.
• Check the syllabus first!

Course Materials

• No required textbook.
• Readings will be posted to Quercus weekly, in advance of lectures.
• Reading materials will include material that is open source or available online from the University library.
• Complete the readings before class.

Tutorials

• Teaching Assistant: Lavania Nagendran.
• Tutorials are held on Fridays online via Zoom.
• Sections: 1:00–2:00 (TUT0001) and 2:00–3:00 (TUT0002).
• Attend the section for which you have signed up.
• Participation counts!
• Tutorial exercises are meant to be completed in class and turned in immediately afterwards.

Assessment

• Graded tutorials: 15%.
  • Assigned exercises completed during tutorials and turned in at the end of each session for grading.
  • One exemption without documentation will be permitted per term.
• Tutorial participation: 10%.
  • Students are expected to have completed any assigned readings or media in advance.
• Zoo assignment: 10%.
  • Due July 25th via Quercus.
• Quizzes: 15%.
  • 6 quizzes throughout the semester; the lowest grade will be dropped (5 quizzes worth 3% each).
  • Available online via Quercus during a specified window (Mondays 6pm–Wednesdays 9pm).
  • Timed, with 15 minutes allocated for each quiz.
  • Question formats include multiple choice, fill in the blank, and matching questions.
  • Complete quizzes independently, without the use of online or other resources or generative AI.
• Term test: 20%.
  • Includes all material from Lectures 1-6 and Tutorials 1-5.
  • Scheduled in June (TBA) and will be held online.
• Final exam: 30%.
  • Focuses on the material covered in Lectures 7-12 and Tutorials 6-11, but general concepts from the preceding lectures will also be tested.
  • Scheduled during the final exam period in August (TBA) and will be held online.

Policies

• Late assignments: accepted with a late penalty of 10% per day (including weekends) for up to 7 days; after 7 days, late assignments won’t be accepted.
• Missed term test: assigned a zero mark unless special consideration is granted.
• Legitimate excuses for missing the deadline or test include Illness or injury, Personal or family emergencies, Bereavement, University-sponsored events.
• Use the ACORN Absence Declaration Tool and speak to Prof. Pugh.

Academic Integrity

• Familiarize yourself with, and adhere to, both the Code of Student Conduct and the Code of Behaviour on Academic Matters.
• All suspected cases of academic dishonesty will be investigated following procedures outlined in the Code of Behaviour on Academic Matters.
• Examples: Using someone else's ideas or words without appropriate acknowledgement, Using or possessing unauthorized aids on tests and exams, Communicating with someone else during an exam or test, Misrepresenting your identity, Creating, accessing, and sharing assessment questions and answers in virtual course groups.

Tips for Success

• Come to class (Mondays @ 3:00–5:00 pm).
• Take notes.
• Ask questions.
• Write down terms that you don’t understand and ask for definitions.
• Attend and participate in tutorials.
• Create a weekly study guide.

What is Evolutionary Anthropology?

• Study of the evolution of the behavioral and biological traits of humans, our primate relatives, and our ancestors, as well as our current biological similarities and differences.
• Examine a wide range of material, including fossils, living primate (e.g., skeletons, behavior, hormones), and DNA.
• Culture: a set of learned behaviours transmitted between generations with non-genetic means to adapt to the environment.
• Behaviour: responses to internal or external stimuli, shaped by evolutionary forces.

Subfields of Evolutionary Anthropology

• Human biology
• Osteology/skeletal biology
• Primatology
• Palaeoanthropology

Examples of Research Topics in Evolutionary Anthropology:

• Human biology
• Osteology/skeletal biology
• Primatology
• Paleoanthropology

What is Evolution?

• Change through time.
• Descent with modification; change through time as species become modified and diverge to produce multiple descendant species.
• A change in allele frequencies from one generation to the next.
• Transformation of species through time, including both changes that occur within species, as well as the origin of new species.
• Evolution ≠ natural selection.
• All life on earth shares a common ancestor.
• Evolution is a broad overarching explanation, built on hypotheses that are tested using the scientific method and are very strongly supported by a lot of evidence.
• The two main pillars of our knowledge of evolution:
  1. Historical record of evolutionary change
  2. Study of the processes of evolutionary change

Why Does Evolution Matter?

• The fascinating diversity of life on Earth, past and present
• How we came to be and what it means to be human
• How human-modified environments are shaping other organisms
• Domestication of plants and animals; protecting them from disease-causing organisms
• Human infectious diseases

The Modern Synthesis

• Scientists working in the 1930s and 1940s brought together ideas about evolution, natural selection, and genetics/Mendelian inheritance.
• Key points included:
  1. Population genetics and Mendel’s principles of inheritance are compatible with evolution.
  2. Evolution occurs by the accumulation of small genetic changes.
  3. Natural selection is the dominant evolutionary force.
  4. Other forces are also at play: mutation, gene flow, and genetic drift.
  5. There are different levels of evolutionary change: micro and macro.
• Evolution is characterized on two scales: Microevolution and Macroevolution.

Microevolution

• Evolution happening on a small scale within a single population, affecting changes in allele frequencies.
• 4 processes: Mutation, genetic drift, gene flow, and natural selection.

Microevolutionary processes

• Mutation: Random change in genetic material; New variation.
• Genetic drift: Random Change.
• Gene flow: Random or Non-random Migration; Hybridization.
• Natural selection: Non-random adaptation, but entirely dependent on environmental pressures.
• Example questions in microevolution: Antibiotic resistance, Darwin’s finches responding to climatic variation.

Microevolution versus Macroevolution

• The accumulation of changes resulting from microevolutionary processes over time can lead to macroevolutionary changes.

Macroevolution

• Refers to evolution at levels higher than the population.
• Coined by T. Dobzhansky.
• Large-scale history of life on Earth.
• Speciation connects micro- to macroevolution.
• Two key points: What is a species? How do new species arise?
• Example questions in macroevolution: How humans are related to other primates, Historical adaptive radiation of Darwin’s finches.

Brief History of Life on Earth

• Extinction is a natural process in the life of a species.
• All extant (living) plants and animals represent 1-4 % of all species that have ever lived.
• Causes of extinction: species competition, meteorites, volcanic activity, climate change, disease, humans.

Mass Extinctions

• 5 mass extinctions:
  1. End Ordovician extinction (439 mya): Caused by changes in sea levels and atmospheric and ocean chemistry. Affected 85% of marine organisms.
  2. Late Devonian extinction (364 mya): Caused by climate change. Affected marine invertebrates and fish.
  3. Permian-Triassic extinction (251 mya): Caused by volcanic activity, climate change, meteorite impact. Earth’s worst mass extinction (the “Great Dying”); 95% of all species went extinct.
  4. End Triassic extinction (199-214 mya): Caused by volcanic activity and global warming. Wiped out many amphibians and mammal-like reptiles – marks an adaptive radiation of dinosaurs.
  5. Cretaceous-Tertiary extinction (65 mya): Caused by large meteorite impact. Led to the extinction of the dinosaurs.
• The sixth mass extinction?
  • Are we approaching another global mass extinction? Extinction rates have been rising over the last 500 years
  • International Union for Conservation of Nature (IUCN) report.
• ANTB14 will focus specifically on primate and human evolution but it is important to contextualize against all life on Earth.
  • Where do we fit in the Tree of Life?
    • Earth: 4.6 bya
    • First primates: ~65 million years ago (mya)
    • First hominins: 6-7 mya

Geological Time

• Geological Eons
• Geological Eras
• Geological Periods
• Geological Epochs

Precambrian Time

• 90% of Earth’s history
  • The Earth forms: No evidence of life
  • Earliest life forms evolve in the seas: the prokaryotes
  • Oxygen atmosphere and eukaryotes evolve
  • Origin and evolution of more complex forms; comprised of three eras – Paleozoic, Mesozoic, Cenozoic

Paleozoic Era

• Cambrian Explosion
• First early vertebrates – primitive jawless fish
• End Ordovician mass extinction
• Earliest land plants
• Late Devonian mass extinction
• Amphibians evolve
• First reptiles evolve
• Permian-Triassic mass extinction
• Reptiles take over as the dominant land animals; adaptive radiation of therapsids

Mesozoic Era – “Age of the Reptiles”

• Early dinosaurs evolve. Therapsids decline. First egg-laying mammals (monotremes) appear
• End Triassic extinction
• Dinosaurs are the dominant reptile on land. First bird appears. First placental mammals evolve
• Dinosaurs rule the earth
• Cretaceous-Tertiary extinction (K-Pg)

Cenozoic Era – “Age of the Mammals”

• Mammals diversify. First primates appear
• Sea mammals evolve from terrestrial ungulates (hoofed animals)
• Many modern mammals, whales and birds present. Ape radiation
• First hominins
• Origins of agriculture
• Genus Homo
• Homo sapiens

Review of Genetics and Terminology

• Cells
• Nucleus
• Chromosome
• DNA
• Gene
• 2 types of DNA: Nuclear DNA and Mitochondrial DNA (mtDNA).
• A genome is all the genetic information of an organism.
• Gene: segment of chromosome’s DNA that codes for protein or trait
• Allele: alternative form of a gene at a particular locus of homologous chromosomes
• Discovered by Mendel in his plant breeding experiments
• One inherited from each parent via meiosis
• Genotype vs. phenotype
  • The genotype is the alleles that an individual has
  • The phenotype is the physical expression (incl. behavior)
• An individual’s alleles for a specific gene can be described as homozygous or heterozygous
  • Homozygous means there are two copies of the same allele for a gene
  • Heterozygous means there are two different alleles for a gene
• The dominance of one allele over another can dictate the expression of a trait (phenotype)
  • Dominant alleles are always expressed
  • Recessive alleles are not expressed in the presence of a dominant allele
• Gene expression via protein synthesis
• The phenotype is the physical expression of the genotype.
• The phenotype is the target of selection.

Inheritance

• Mendelian traits are discrete and controlled by a single gene
• Polygenic traits:
  • Continuous variation.
  • Phenotype is determined by more than one gene
• Pleiotropic traits:
  • Change in one gene impacts multiple traits
• Some traits are also impacted by the environment in which the organism lives
  • Phenotypic plasticity
  • For example, an individual that does not have adequate nutrition early in life will have stunted growth
• Epigenetics:
  • Change in gene expression without a change in the DNA sequence
  • Environmental influences on gene expression
  • E.g., Gene regulation via DNA methylation
• Epigenetics Example: Dutch Famine of 1944–45 (Hongerwinter)
  • Children of pregnant women exposed had greater disease risk of cardio-metabolic disorders, mental health issues, and mortality
  • Change in methylation rate (famine, cold, psychosocial stress)
  • Passed on to subsequent generations

Reminders

• Quiz #1 (closes Wednesday at 9pm).
• Friday: First tutorial.
• Next week: Selection.