ANTHROPOLOGY Lecture

Dr. Linnea Wilder

Course schedule:

• Part 1: Evolution, Genetics

• Midterm 1: October 21st

• Part 2: Non-human primates

• Midterm 2: November 13th

• Part 3: Fossils, Hominid Evolution

• Final Exam: Tuesday December 10th 11:30am-2:29 pm

What is Anthropology?

• The study of humans

  • Past and present

  • Examines humans in context (social, cultural, biological)

• Traditionally there are four fields

• Cultural

• Linguistic

• Archaeology

Key points

• What is science?

• What are the misconceptions about science, and why are they not true?

• What is a theory?

• Definition of evolution

• What are the misconceptions about evolution, and why are they not true?

• How did views of creation/evolution/the earth change in the 17th and 18th centuries?

Ways of knowing

• How do you know what you know?

• There are many methods of knowing, including:

  • Traditional

    • Something Is true because it has always been true

  • Intuitive

    • Something is true because it feels true

  • Authorative

    • Something is true because someone said ut was true

  • Scientific

    • Something is true because it has been empirically demonstrated and is not likely to be untrue

Can we ever really know anything

Of course, Just remember that perception matters, and some knowledge is more likely to be true

• Myths - things we generally believe to be true, but aren’t

  • Can be dangerous if they affect or ideas and perceptions of others

• Science - much more likely to be true

  • Often misunderstood

Two main sources of personal knowledge

• Personal experience (our own direct observations)

• Input from others, acceptance of someone else’s knowledge or claims (often verbal, but not necessarily verbal)

Personal experience is fairly straightforward - you learn various things about the world through experience

• But your senses can be deceived, accidentally or intentionally

Input from others is common, and necessary, and often very important

Usually important in at least three cases:

•

1. You weren’t there or can’t get there – any social interactions taking place outside of your direct observation you only know about through reports of others or behavioral indications from others

•

2. You don’t know how to evaluate the information – others have learned evaluation methods you don’t yet know

•

3. You don’t have the time or the resources to evaluate the information – others have experience with something and it’s much more efficient to find out from them than to try to gather information through your own experience

Problems

• Experts are people too, their information could be wrong, misleading, or manipulative

• Biggest and most important search is for an authority who is reliable and who is trustworthy

Science

• Science combines social acquisition with personal experience

• In principle requires every authority to provide clear and public recipe to show how you can observe the results yourself directly

• It takes the acquiring knowledge from authoritative others and turns it into acquiring knowledge from personal experience

What is science?

• Science:

  • (from Latin scientia, meaning "knowledge")

• a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the natural world

• i.e. method for explaining natural world

Science is a method to test hypotheses about the natural world

• Hypotheses are proposed explanations for a narrow set of phenomena.

• You reject or fail to reject hypotheses

Science neither proves nor disproves, but rather, narrows uncertainty

Science is not

1. Complete

2. Absolute and unchanging

3. Untrustworthy because it changes

4. A mechanism for proving or disproving

5. Guesses

6. Disproof of God or any other belief system

These aspects of Science may cause people who don’t understand the aspects to find science untrustworthy

Scientific theories

• Theories are not guesses

• Accumulation of large data sets (tested hypotheses) can lead to the formation of theories

  • Theories are powerful explanations for a wide rage of phenomena

  • Accepted theories are not tenuous

• Even theories can be disproven, although this very unlikely

Science can only explain physical/natural world

There are limits to science

What is Evolution?

• Evolution is the change in allele frequencies that occurs over time within a population

Misconceptions about evolution

• Not just a theory

  • Theories are supported by a body of evidence (tested and accepted hypotheses).

  • Evolution is a theory in the same way atomic theory is.

• Humans did not evolve from chimpanzees

  • Humans share a common ancestor with chimpanzees.

  • Chimps are our closes living relative, not a direct ancestor

• Evolution does not have an agenda

  • Evolution has not determined the way species look or behave, it doesn’t grant organisms what they need

  • It has provided ways of responding to the environment in particular ways

• Its not random

• Selection does not work for the good of the species

• It operates on the level of the individual

• Example

  • High - versus low-fecundity females

  • High fecundity favored even at species’ expense

• Evolution doesn’t indicate progress

• Evolution is a process of change, but that does not necessarily mean improvement

Before Charles Darwin

Common views:

• Earth young (~6000y)

• Species divinely created

• Species immutable

Emerging scientific views:

• Earth old

• Earth’s surface has changed over time

• Plants & animals have changed

Scala naturae

(or Great Chain of Being):

All of creation arranged hierarchically with humans (or God and his angels) at the top

• Humans and animals separate

• Fixity of species

The 18th century, the age of reason

• Interested in interpretation, relationships of different phenomena

• Carl Linnaeus

  • Swedish botanist, father of modern taxonomy

  • Binomial nomenclature, Genus species

• Jean-Baptise Lamarck

  • Inheritance of acquired characterist

Catastrophism (17th C): • Based on the Bible

• Earth is 6000 years old

• There must have been many catastrophic events in order to explain how it reached its present shape in such a short time
  • Charles Lyell and James Hutton • Uniformitarianism
  • Same physical laws that shape the Earth today also shaped it in the past, continuous and uniform processes

• Present features are the result of small, incremental changes

10/2/2024

Charles Darwin Was trying to become a doctor like his father but became a naturalist, something about the beagles, he travelled with them

He got sea sick really easy made him study more on land

South America

• Spent most of his time on land while the Beagle surveyed the coast

• Observed geological as well as biological phenomena

• First tidbits of evidence began to emerge

• He was curious why the Megatherium went extinct

4 different species of Finch, a type of bird

• They had different types of features

Darwin asked why do these birds look different in different islands/habitats and how did it happen

On The Origin of Species By Means of Natural Selection (1859)

• Conflict with religious beliefs (including those of wife)

• Wanted to build a solid argument

• Catalyst: Interactions with Alfred Russell Wallace

  • Wallace came up with an idea saying he would publish it unless Darwin didn’t

Why? Adaptations

• Changes in physical structure, function, or behavior that allow an organism or species to survive and reproduce in a given environment

• Different animals are adapted to different environments

• They do not adapt to their environment

How? - Natural Selection

• The process by which some organisms, with features that make them more adapted to the environment, preferentially survive and reproduce thereby increasing the frequency of those features in the population

Example: Peppered Moths

Darwin’s 3 Postulates of Natural Selection

1. There is a struggle for existence.

   1. (i.e. there are more born than will survive)

2. There is variation in features related to survival and reproduction.

   1. (i.e. we are all different)

3. This variation is passed from generation to generation.

   1. (i.e. differences are heritable)

These three postulates make evolution by means of natural selection inevitable.

Evolution! The Process of Change Over Time

• Species are dynamic, changing populations of individuals

Stabilizing Selection

It could be disadvantageous

Individuals Don’t Evolve, Populations Do

• Natural Selection acts on the individual

• But POPULATIONS evolve

Selection is not Directional

Evolution doesn’t equal Speciation

Darwin’s Dilemmas

#1: How are traits passed between generations?

• Relates to P3: traits must be heritable!

• In Darwin’s time, people (including Darwin) believed in blending inheritance (traits of parents blend in the offspring)

  • BUT everyone would look the same after several generations, where does variation go?

#2: How is Variation Created/maintained?

• Relates to P2: there must be variation in a trait for natural selection to act

• How is variation maintained if natural selection eliminates it?

• Where do novel forms come from if not already present in original population?

#3: How do you reconcile seemingly deleterious traits with natural selection

• Relates to struggle for existence.

  • Goal of existence is to reproduce (at least from your genes’ point of view)

• Natural selection is not the only force acting on individuals: Sexual Selection

10/4/24

Sexual selection

• Selection for traits that increase mating success

• Leads to changes in frequency of those traits that are either attractive to members of the opposite sex or helpful in competition either members of the same sex

• A trial can be favored by selection if it increases mating success even if it lowers survival

Intrasexual (=within sex): favors the ability of one sex to compete directly with one another for fertilizations, for example by fighting

Intersexual (=between sexes)

1. Mate conflict occurs when the genetic/reproductive interests of females and males diverge

   • Can be mechanical or behavioral

   • Can lead to either one sex having the advantage or to an arm’s race between the sexes

2. Mate choice favors traits that attract the opposite sex (usually female choice)

   • Females are using the choosy sex, and may be attracted to traits that indicate:

     • Direct material benefits

       • Access to resources, protection from aggression, investment in her and her offspring

     • Indirect benefits

       • Good genes, as indicated, for example, by the fact that the Malle can survive despite possessing the attractive trait (handicap hypothesis)

       • Good genes, reflected in the trait (honest signal hypothesis) - traits often display fitness of male (e.g. parasite load, testosterone levels) in a way that is impossible to fake - some overlap with handicap hypothesis

     • Nothing

       • Arbitrary, nonadaptive traits (but. Possessing them will make the offspring more attractive?)

         • Thought to evolve through runaway selection, where traits and the preference for those traits coevolve together

Sexual Selection and Sexual Dimorphism

• Sexual dimorphism = difference between the sexes in some trait

  • Usually due to sexual selection

  • Body and canine size most common, due to intersexual male-male competition

  • More common when trait is maladaptive or is honest signal of testosterone

Artificial Selection

• Humans have domesticated and selectively bred plants and animals

• Rapid changes have been achieved in few generations

• Dogs and pigeons are good examples

Darwin’s Difficulties Explaining Variation

Questions

• How are traits passed on? Is there blending inheritance?

• How is variation maintained if natural selection eliminates it?

• Where do novel forms come from if they are not already present in the original population?

Mechanism of Heritability

Gregor Mendel

• Worked under a bishop and had to turn to religion to get an education because he was poor. Was told to study with plants, peas, because it went against the religion to work on animal sex

• Discovered laws of inheritance

• Bred garden pea plants (1856-1863)

• Worked with traits with two variants

DNA -  A History

1900s - Mendel’s work resurfaces spurs more research

1950s - Walther Flemming

• Discovered a fibrous structure inside nucleus of cells

• Called it chromatin

  • Chromosomes

  • Identified the process through which it separates during cell division: mitosis

Chromosomes

• ‘Bundles’ of DNA

• 46 total in humans (23 homologous (=matching) pairs)

  • 22 pairs are somatic chromosomes

  • 1 pair are the sex chromosomes (XY or XX)

• Species variation in # of chromosomes (e.g. chimpanzees have 48)

Late 1900s - Walter Sutton & Theodor Boveri

• Worked independently of each other

• Roundworm embryos

• Genetic material that is passed from parent to child is in the chromosomes

  • Chromosome theory

Call Division and the Role of Chromosomes in Inheritance

• Karyotype = the picture of an individual’s stained chromosomes, arranged in homologous pairs, laid out from largest to smallest

  • Homologous pairs= set of matching chromosomes

• Understanding chromosomes was key to understanding inheritance, which in turn is key in understanding evolution

Cell Division

• Mitosis: “Ordinary” or somatic cell division (all cells other than egg and sperm)

• Meiosis: Sex cell division producing gametes

  • Produces haploid cells

  • Variation can be introduced through mutation and recombination

Chromosomes and Mitosis

• “Ordinary” or somatic cell division (all cells other than egg and sperm)

  • Diploid (paired) chromosomes

  • Chromosomes replicate before cell division, otherwise each time there was a division there would only be half the genetic material

• Sex cell division producing gametes

• Haploid (not paired) chromosomes

  • Halves the number of chromosomes so that when there is a union of egg and sperm the total chromosomes number remains the same

Mendel’s Experimental Results

• Gene=a section of DNA on a chromosome that codes for a particular trait

• Alleles = alternate forms of a gene
  • If alleles are the same: homozygous
  • If alleles are different: heterozygous

• Genotype: Specific alleles for a trait.

• Phenotype: Physical expression of a trait.

• Dominant Allele: Masks effects of other alleles.

  • Yellow is dominant in this example (A)

• Recessive Allele: Masked by dominant alleles.

  • Green is recessive in this example (a)

Recombination: Crossing over in meiosis.

• Independent assortment of traits.

• Segregation may not be independent if the loci are physically near one another

• Crossing-over

  • New gene combinations increase variation.

10/7/24

DNA and Genetic Expression

Date: 10/7/2024

Key Points

• DNA

  • Structure and function

  • Replication and protein synthesis

  • Transcription and translation processes

• Genes

  • Definition and function

  • Variants (alleles)

• Mitochondrial DNA (mtDNA)

  • Characteristics and inheritance

• Mutations

  • Types and effects on phenotype

• Genetic Concepts

  • Polygenic traits

  • Pleiotropy

DNA History

• Discovery

  • Watson and Crick published the double-helix structure in 1953 (Nobel Prize in 1962).

  • Based on Rosalind Franklin's x-ray images.

• Significance

  • Understanding DNA structure aids in understanding its function.

  • DNA replication and its role in evolutionary timing.

What is DNA?

• Definition

  • Deoxyribonucleic acid (DNA) is a double helix structure.

• Components

  • Sugar and phosphate backbone.

  • Nucleotide bases: Adenine (A), Guanine (G), Cytosine (C), Thymine (T).

  • Base pairing rules: C with G, A with T.

What are Genes?

• Definition

  • Segments of DNA that serve as the fundamental unit of heredity.

• Variants

  • Alleles are different forms of a gene.

  • Humans possess approximately 20,000-25,000 genes.

Mitochondrial DNA (mtDNA)

• Characteristics

  • Found in mitochondria, codes for 37 genes.

  • Inherited maternally without recombination.

  • More conserved and shorter than nuclear DNA.

• Mitochondrial Eve

  • The most recent common matrilineal ancestor of all humans, estimated to have lived 100-200kya in East Africa.

Applications of DNA

• Estimating Ancestry

  • Molecular clock techniques to estimate species divergence.

• 23 & Me

  • Ancestry reports including Neanderthal ancestry.

  • Example: Linnea has 262 Neanderthal variants, less than 72% of customers.

DNA Replication

• Process

  • Unzipping of DNA strands.

  • Addition of complementary bases.

  • Proofreading mechanisms to ensure accuracy.

• Error Rates

  • One error in one billion bases replicated.

  • Errors in gametes can be passed to future generations.

From Genes to Proteins

• Transcription

  • Occurs in the nucleus where DNA is transcribed into messenger RNA (mRNA).

  • RNA uses uracil (U) instead of thymine (T).

• Translation

  • Occurs in the cytoplasm where ribosomes read mRNA to produce amino acids.

  • Codons (3-letter DNA sequences) correspond to specific amino acids.

Protein Function

• Types of Proteins

  • Structural: Provide support (e.g., collagen, keratin).

  • Contractile: Facilitate movement (e.g., myosin, actin).

  • Transport: Carry substances (e.g., hemoglobin).

  • Storage: Store nutrients (e.g., casein, ferritin).

  • Hormonal: Regulate metabolism (e.g., insulin).

  • Enzymatic: Catalyze biochemical reactions (e.g., sucrase, trypsin).

  • Protective: Immune response (e.g., immunoglobulins).

Sources of Variation - Mutations

• Types of Mutations

  • Point Mutations: Alteration in a single base pair; effects on phenotype vary.

  • Chromosomal Mutations: Involves segments or entire chromosomes; always affects phenotype.

Gene Regulation and Cell Differentiation

• Mechanism

  • All cells share the same DNA, but gene expression varies.

  • Example: PAX6 gene influences eye formation in fruit flies.

  • Involvement of microRNA (miRNA) and long noncoding RNA (lncRNA).

Beyond Mendel – Polygenic Traits and Pleiotropy

• Polygenic Traits

  • Traits influenced by multiple genes.

• Pleiotropy

  • A single gene can affect multiple traits.

  • Example: 'Ay' allele in mice demonstrates pleiotropic effects.

This note summarizes the key concepts of DNA, genetic expression, and their implications in heredity and evolution, providing a comprehensive overview of the subject matter discussed in

10/9/2024

Modern Synthesis Notes (10/9/2024)

Key Points (Page 2)

• Forces of Evolution

  • Understand the 4.5 forces of evolution and their impact on variation.

• Population Genetics

  • Definition and significance in studying evolution.

• Calculating Allele Frequencies

  • Methods to determine if evolution has occurred.

• Natural Selection and Behavior

  • How natural selection influences behavior.

• Constraints on Evolution

  • Limits and constraints affecting evolutionary processes.

Forces of Evolution (Page 3)

• Natural Selection

  • A primary evolutionary force but not the only one.

• Other Forces

  • Genetic Drift

  • Gene Flow

  • Mutation

• Natural Selection's Limitation

  • Cannot create variation.

Genetic Drift (Page 4)

• Definition

  • Random changes in allele frequency across generations.

• Effects

  • Reduces genetic variation.

• Key Concepts

  • Bottleneck Effect: Significant reduction in population size leading to decreased genetic variation.

  • Founder Effect: Small initial population size can lead to increased prevalence of rare traits.

Examples of Genetic Drift (Page 5-6)

• Northern Elephant Seals

  • Population reduced to 20, now 20,000 but with low genetic variation.

• Cheetahs

  • Survived a mass extinction, leading to conservation issues.

• Human Genetic Diversity

  • Genetic diversity comparable to a population of 15,000 individuals.

• Founder Effect Examples

  • Martha’s Vineyard deaf community and the Manx cat.

Gene Flow (Page 8-9)

• Definition

  • Movement of genes between populations through migration.

• Impact

  • Increases genetic variation.

• Human Gene Flow

  • Increased over the last 500 years; few isolated populations remain.

  • Historical marriage patterns indicate limited distance in mate selection.

Mutation (Page 10)

• Definition

  • Random changes in genes or chromosomes that can create new traits.

• Frequency

  • Occurs during cell division; most mutations are neutral or harmful.

• Significance

  • Ultimate source of new genetic variation.

Population Genetics (Page 11-12)

• Definition

  • Study of genetic composition changes in populations over time.

• Allele Frequencies

  • Calculation example with pea plants to illustrate allele ratios.

Population Genetics: PKU

• PKU

  • Inability to metabolize phenylalanine

  • Homozygous recessive

  • 1 in 10,000

  • Assume 2,000 out of 10,000 for this exercise

Random Mating and Genotypic Frequencies (Page 14-15)

• Random Mating

  • Gene frequency calculations (p and q).

• Genotypic Frequencies

  • Probabilities of different genotypes resulting from random mating.

Hardy-Weinberg Equilibrium (Page 16)

• Definition

  • A state where allele frequencies remain constant; indicates no evolution.

Natural Selection and Gene Frequencies (Page 17-18)

• Impact of Natural Selection

  • Selection against certain genotypes (e.g., PKU).

• Mechanism

  • Operates on phenotypes, not directly on genotypes.

• Environmental Influence

  • The strength and direction of selection depend on environmental factors.

Modern Synthesis (Page 19)

• Integration of Theories

  • Combines genetics and natural selection to explain evolution.

Genetics of Continuous Variation (Page 20-21)

• One and Two Genes

  • Distribution of traits (e.g., height) follows a bell curve due to multiple genes.

Natural Selection and Behavior (Page 22-24)

• Behavioral Flexibility

  • Example: Soapberry bugs and mate guarding behavior.

• Evolution of Behavior

  • Variation in behavior affects reproductive success and is heritable.

Constraints on Adaptation (Page 25-28)

• Correlated Characters

  • Example: Darwin’s finches with beak depth and width.

• Local vs. Optimal Adaptations

  • Adaptations may be limited by environmental factors.

• Other Constraints

  • Developmental constraints and evolutionary trade-offs.

Definition of Evolution (Page 29)

• Change in Allele Frequency

  • Evolution defined as changes in allele frequencies due to:

  • Natural Selection

  • Sexual Selection

  • Genetic Drift

  • Gene Flow

  • Mutation

Modern Synthesis Overview (Page 30)

• Production of Variation

  • Sources include mutations, meiosis, recombination, and gene flow.

• Reduction of Variation

  • Caused by genetic drift and natural selection.

10/11

Speciation and Phylogeny Notes (10/11/2023)

Page 2: Key Points

• Definition of a Species

• Biological vs. Ecological Species Concepts

• Mechanisms of Speciation

  • Allopatric, Parapatric, Sympatric Speciation

  • Adaptive Radiation

• Importance of Classification

• Understanding Phylogenetics

• Cladograms: Construction and Interpretation

• Homology vs. Convergence

• Ancestral vs. Derived Traits

Page 3: What Is a Species?

• Life can be categorized into distinct types.

• Species are real biological concepts but can be challenging to define.

Page 4: Defining a Species

• Two main concepts:

  • Biological Species Concept

  • Ecological Species Concept

Page 5: The Biological Species Concept

• Defines species as:

  • Groups of interbreeding organisms.

  • Capable of producing fertile offspring.

  • Reproductively isolated from other groups.

  • Connected through gene flow.

Page 6: Reproductive Isolation

• Causes of reproductive isolation:

  • Genetic incompatibility

  • Anatomical incompatibility

  • Ecological separation

  • Lack of phenotypic match

Page 7: Genetic Incompatibility

• Results in:

  • No offspring or hybrid infertility (e.g., mules).

  • Chromosome differences (e.g., horses vs. donkeys).

Page 8: Anatomical Incompatibility

• 'Lock & Key' Hypothesis: Specialized genital morphology prevents mating between different species.

Page 9: Ecological Separation

• Example: Ligers (lion/tiger hybrids) exist only in captivity due to habitat separation.

• Fertile females exist, raising questions about species classification.

Page 11: Lack of Phenotypic Match

• Example: Guenons show genetic similarity but significant phenotypic differences, promoting reproductive isolation.

Page 13: The Ecological Species Concept

• Reproductive isolation is not necessary.

• Natural selection maintains species distinctiveness.

Page 15: Hybrid Vigor

• Example: Coywolf (wolf/coyote/dog hybrid) shows mixed traits and successful adaptation, yet remains a distinct species.

Page 17: How Do New Species Form?

• Mechanisms of speciation:

  • Allopatric Speciation

  • Parapatric Speciation

  • Sympatric Speciation

  • Adaptive Radiation

Page 18: Allopatric Speciation

• Involves geographic isolation leading to reproductive isolation and natural selection.

Page 22: Adaptive Radiation

• Rapid diversification occurs to fill ecological niches.

Page 23: Speed of Speciation

• Gradualism: Slow, gradual changes.

• Punctuated Equilibrium: Rapid changes in response to environmental shifts.

Page 26: Why Classify?

• Organizes the diversity of life and aids in identifying organisms.

Page 27: History of Classification

• Developed by Carl Linnaeus, known as the "father of modern taxonomy."

Page 28: Levels of Classification

• Taxonomic hierarchy includes:

  • Kingdom

  • Phylum

  • Class

  • Order

  • Family

  • Genus

  • Species

Page 29: Naming Organisms

• Binomial Nomenclature: Two-part naming system (Genus species).

Page 35: Phylogenies

• Study of diversification and relationships among living organisms.

Page 41: Homology vs. Convergence

• Homology: Similar traits due to shared ancestry.

• Convergence: Similar traits due to similar selective pressures.

Page 48: Ancestral vs. Derived Characters

• Ancestral: Traits inherited from ancestors.

• Derived: Modified traits that are diagnostic.

Page 51: Taxonomy: Naming Names

• Names reflect degrees of relatedness (e.g., Genus Pan for chimpanzees and bonobos).

This note summarizes the key concepts and details from the transcript on speciation and phylogeny, providing a structured overview of the material

10/14

Classification and Introduction to Primates

Date: 10/14/2024

Page 2: Key Points

• Phylogenetics

  • Study of evolutionary relationships among species.

• Cladograms

  • Ability to read and construct diagrams that show these relationships.

• Homology vs. Convergence

  • Homology: Similar traits due to shared ancestry.

  • Convergence: Similar traits due to similar selective pressures.

• Ancestral vs. Derived Traits

  • Ancestral: Traits inherited from ancestors.

  • Derived: Traits modified from ancestral conditions.

• Importance of Studying Primates

  • Understanding mammalian traits and evolution.

Page 3-4: Naming Organisms

• Scientific Naming

  • Importance of using scientific names for clarity.

  • Example: Puma (Puma concolor) has multiple common names (mountain lion, cougar, etc.).

Page 5-7: Classifying Species

• Phylogenetic Relationships

  • Understanding which species are more closely related.

  • Example: Jaguar (Panthera onca) vs. Ocelot (Leopardus pardalis) vs. Lion (Panthera leo).

Page 8-9: Understanding Phylogenies

• Phylogenies

  • Study of diversification and relationships among living forms.

• Cladograms

  • Visual representation of evolutionary relationships.

Page 11-12: Reading a Cladogram

• Clades

  • Groups of animals derived from a common ancestor.

  • All members of a clade are more closely related to each other than to those outside the clade.

  • Can be nested

Page 14-15: Homology vs. Convergence

• Homology

  • Similar traits due to shared ancestry.

• Convergence

  • Similar traits due to similar environmental pressures.

• Hierarchical Classification (nested boxes)

  • Evolution from common ancestry explains this pattern

Page 17: Why Reconstruct Phylogenies?

• Understanding Evolution

  • Helps in understanding the evolution of traits like bipedalism in humans and other primates.

• Species that are more similar are assumed to be more closely related.

Page 18: Comparative method

• Function of behavior or morphology deduced

• Independent evolutionary events counted

Page 21-23: Problems Due to Ancestral Characters

• Ancestral vs. Derived Characters

  • Ancestral traits are not diagnostic; derived traits are modified and diagnostic.

• Identifying Ancestral Characters

  • Traits that appear early in development.

  • Out-groups

Page 24-25: Taxonomy: Naming Names

• Hierarchical Classification

  • Example: Genus Pan (chimpanzees and bonobos)

  • Family Hominidae.

  • Superfamily: Hominoidea

  • Order: Primates

  • Class: Mammalia

Page 26-30: Primate Overview

• Why Study Primates?

  • To understand human evolution and what makes humans unique.

• Common Characteristics of Primates

  • Shared traits among primates that inform our understanding of human evolution.

Page 33-36: What Makes a Mammal and a Primate?

• Mammalian Traits

  • Hair, mammary glands, live births, and specialized teeth.

• Primate Traits

  • Grasping hands and feet, nails instead of claws, and large brains.

Page 37-40: Defining Traits of Primates - Hands and Feet

• Grasping Ability

  • Opposable thumbs and toes.

• Nails vs. Claws

  • Enhanced sense of touch.

Page 39-42: Defining Traits of Primates - Vision

• Binocular Vision

  • Depth perception and hunting adaptations.

• Color Vision

  • Trichromacy in Old World primates.

Page 46-49: Defining Traits of Primates - Dentition and Life History

• Unspecialized Dentition

  • Versatile diet with different tooth types.

• Life History Traits

  • Increased investment in offspring and slow maturation.

Page 50-51: R vs. K Selection

• Reproductive Strategies

  • K-selected species (like great apes) invest heavily in fewer offspring.

Page 52-54: Defining Traits of Primates - Cognition

• Encephalization Quotient (EQ)

  • Brain size relative to body size, indicating cognitive abilities.

Page 55: Defining Traits of Primates - Habitat

• Habitat Adaptation

  • Primates primarily found in tropical regions

10/16

Introduction to Primates

Date: 10/16/2024

Key Points

• Understand each primate trait discussed, and why they might have evolved.

What Makes a Mammal? (Page 3-4)

• Mammalia Characteristics:

  • Named for mammae (breasts).

  • Presence of hair or fur.

  • Ability to maintain body temperature (endothermy).

  • Mammary glands for feeding young.

  • Different types of teeth (incisors, canines, molars).

  • Pentadactyl limbs (five digits, though lost in some orders).

  • Live births (most species).

  • Larger cerebrum compared to other vertebrates.

  • Three middle ear bones.

What Makes a Primate? (Page 5-6)

• Eutherian Mammals:

  • Primates are specifically eutherian mammals, gestating fetuses until a relatively late stage.

  • Reproductive behavior is influenced by mammalian anatomy.

  • Female investment in offspring is obligatory, while male care varies.

• Characteristics of Primates:

  • No single unique trait; instead, a suite of characteristics:

    • Grasping hands and feet.

    • Nails instead of claws.

    • Stereoscopic vision.

    • Slow maturation.

    • Large brain size.

    • Generalized dentition.

Defining Traits of Primates (Pages 7-19)

• Hands and Feet:

  • Grasping hands and feet with opposable thumbs/big toes.

  • Nails instead of claws enhance the sense of touch.

• Locomotion:

  • Hindlimb-dominated locomotion.

• Vision:

  • Decreased reliance on smell; increased reliance on vision.

  • Less prognathism (shorter faces).

  • Orbital convergence for binocular vision and color vision.

• Binocular Vision:

  • Reduces overall visual field but enhances depth perception.

  • Evolutionary adaptation for hunting and arboreal living.

• Color Vision:

  • Most Old World primates are trichromats (three types of cones).

  • Color vision aids in dietary adaptation and social interactions.

• Bony Eye Sockets:

  • Complete postorbital bar protects eyes and correlates with reliance on vision.

• Dentition:

  • Unspecialized dentition allows for dietary versatility.

  • Four distinct tooth types: incisors, canines, premolars, molars.

Life History Traits (Pages 20-22)

• Investment in Offspring:

  • Typically one offspring at a time.

  • Slow maturation and extended maternal care.

• Reproductive Strategies:

  • R vs. K selection spectrum:

    • R-strategy: high offspring number, low parental care (e.g., oysters).

    • K-strategy: low offspring number, high parental care (e.g., great apes).

  • Humans are K-selected overall but exhibit some r-selected traits.

Cognition (Pages 23-25)

• Encephalization:

  • Larger brain-to-body size ratio than other mammals.

  • Increased dependence on learning and behavioral flexibility.

• Encephalization Quotient (EQ):

  • Measures brain size relative to body size.

  • Capuchins vs. Squirrel monkeys illustrate different developmental patterns.

Social Structure and Habitat (Pages 26-27)

• Social Structure:

  • Most primates live in social groups; even solitary foragers maintain loose networks.

• Habitat:

  • Primarily found in tropical regions but have adapted to various habitats.

The Origin of Primates (Pages 28-30)

• Hypotheses:

  • Visual predation hypothesis: adaptations for hunting insects.

  • Arboreal model: adaptations for tree-dwelling life.

• Early Primates:

  • Plesiadapiforms (65-54 MYA): early primate-like animals with adaptations for arboreal life but not true primates.

• Not Primates:

  • Flying lemurs (colugos) are not true lemurs and do not possess flying capabilities.