lecture 1 intro and scientific method

Anthropology 101: Human Biological Evolution

Lecture 1: Intro & Scientific Method

Dr. Leanna WolfeLAWolfe@aol.com

Office AHSDrop In Hours:5:00-6:30 PM AHS 303

Anthropology = the study of humankindFour subfields of Anthropology

Applied Anthropology

Biological Anthropology

Archeology

Linguistic Anthropology

Cultural Anthropology

The Subfields of Biological Anthropology

Anthropology: Study of Humans+ How Evolution Works

Charles Darwin Peppered Moths in Industrial England

How Does Evolution Works in Other Primates?

MacaquesRing-tailed Lemur

What is the History of the Human Lineage?

A. afarensis A. africanus A. aethiopicus

H. erectus H. sapiens

How did Evolution shape hominin adaptations?

• Bipedality

• Tool use

• Behavior• Culture

How does Evolution shape minds, bodies, & behavior in modern humans?

Introduce yourself to your neighbor.

What do you think/how do you feel about studying anthropology? Do you believe in Natural Selection?

Course Requirements

How to do well in this class• Do the reading ahead of class• Come to class on time• Ask questions• Pay attention• Be curious• Do the assignments on time• Take notes during lecture• Access lecture notes online• Form a study group

• Two Midterm Exams with short in-class Essays

• Two Take-Home Essays• In-class activities• Final Exam (no essays)• Zoo Project (Class Trip on

Saturday June 28)• Schedule of Assignments &

Exams on Syllabus• Extra Credit Options

Class Website

• To access go to http://drleannawolfe.com/physicalanthro.html

• Essay Topics• Link to Power Points• Link to Zoo Project• Links to Assigned Articles• Links to Class Lectures• Links to Extra Credit• Exam Review Information

Important Dates and Enrollment Changes

• Last day to drop a class without receiving a “W” June 18

• Last day to drop the class receiving a “W” July 9

• Only 3 attempts allowed per class

• If you miss class during the 1st week, I will drop you• If you miss 2 classes at all, I can drop you.

3 in a row, I will drop you. Unless you speak with me and make arrangements

• But, its your responsibility to drop if you aren’t attending!!

Plagiarism Cheating

• Turning in work done by another person

• Copying the words of another person

• Presenting the ideas of another person as your own without proper citation

• Copying and pasting text from a website

• Looking at another person’s test, homework etc when asked to work independently

• Use of study aids when asked to work from your own memory

• Sharing your work with another student

To understand why we are the way we are, we need to know

• How the scientific method operates

• Science is essential to our lives• You need to understand how it

operates• You need to be able to evaluate

science in the media• Measure things as a way of

testing hypotheses

What is Science?

• Process of explaining natural phenomena through observation and experimentation

Measure observed phenomena

Test hypotheses

Follow the Scientific Method

J.J. "Mad Scientist". common.wikimedia.org 02/25/08. 03/31/06 http://commons.wikimedia.org/wiki/Image:Mad_scientist.svg

What is a hypothesis?

• provisional explanations requiring verification or falsification through testing

proposes a causal relationship between two variables

Predict how X will affect Y

• (X) Independent variable(s) – things that are– Water, sunlight, soil

• (Y) Dependent variable(s) – things that are affected

– Height of plant– Thickness of roots– Number of leaves

The Scientific Method• Question• Read• Hypothesis• Methods• Collect data

Rigorous & replicable Quantitative Statistics Falsifiable

• Relate back to your hypothesis

Repeat!

The process of science generates a theory

• broad statement of scientific relationships• underlying principles• substantially verified through the testing of hypotheses• A broad explanatory statement of scientific fact

• It guides the formation of hypotheses to explain things observed in the world

• It has been supported by repeated and varied testing of related hypotheses

• Hypothesis - narrow focus explaining the relationship between a few specific phenomena

A theory

IS• A theory is backed by lots of evidence• A theory is a statement of scientific fact• A theory is open to evaluation and testing• A theory has the potential to be falsified/revised

IS NOT• A theory is NOT a hunch or a guess• A theory is not an absolute• A theory is not unknowable or immeasurable

Any proposition that is stated as absolute or doesn’t allow for

the possibility of falsification is not a scientific hypothesis.

Why we use the scientific method

• Testable (falsifiable) hypotheses• Replicable methods• Competition and collaboration among scientists

• New theories gain acceptance Explain odd findings that older theories can’t explain Lead to new TESTABLE predictions Lead to new discoveries

• All results and theories open to debate & refinement

Creationism & Intelligent Design

• Biblical explanation for the origin of the universe, species, humans

relies on faith in bible not evidence Not open to testing = absolutes

• Argue that evolution is an unproven theory

• Intelligent Design = creationism No testable predictions regarding the designer or

creator Try to disprove or discredit evidence for evolutio

Can you Understand Evolution and Be Religious?

Geologic Time Scale

• Measures history of Earth – 4.5 billion years• Organizes history of Earth into various units• Eon > Era > Period > Epoch• Important to understand the scale and pace of evolution

Solar System forms

Earth forms

Life appears on Earth

3.5 Billion YA

Mesozoic

CenozoicPhanerozoic Eon

Paleozoic

Animal life diversifies starting in the Paleozoic

Marine invertebrates

Firstvertebrates

Arthropods

Age of Fishes, 1st amphibians

& insects

Age of amphibians, 1st reptiles, 1st great

insect radiation

570 mya 500 430 395 345 280 225 190

Cambrian

Expansion of reptiles,decline of amphibians

Ordovician Silurian Devonian

Carboniferous

Permian

TriassicJurassic & Cretaceous

Paleozoic Era Mesozoic Era

225 190 136 65

1st Mammals (Monotremes) & dinosaurs

Age of dinosaurs1st birds

1st flowering trees (angiosperms)!st Marsupials, Placental mammalsDinosaurs vanish @ 65mya Continent(s) breaking apart

Mammals, birds, insects

flourish

Triassic Period Jurassic PeriodCenozoic EraCretacous

Period

Mesozoic Era

Recognizable fauna of the Mesozoic

Starting in the Mesozoic the earth rearranged itself (200 mya – present)

The Mesozoic: Triassic (225 mya)• Pangea was a single continent• Dinosaurs & small mammals evolve• Pangea HUGE land mass

Hot, arid, seasonal, some coastal areas more humid

Transition fromTriassic to Jurassic

The Mesozoic: Jurassic (190 mya)• 200 mya Pangea starts breaking up

Laurasia & Gondawana• Oceans are barriers to gene flow = new species form• World gets warmer, climate stable when continent splits• Dinosaurs and mammals evolve in this warmer world

The Mesozoic: Cretaceous (136 mya)

• Rise of angiosperms = fruits bearing trees = new foods• Placental mammals evolve• Adaptive Radiation

Gymnosperms

Angiosperms

The Mesozoic: Cretaceous (136 mya)

Continents & Climate @ 94 mya

Life’s great until mass extinction of dinosaurs 65 mya

Primates finally start to enter the scene, 65 mya

65 54 34 23 5

Paleocene Epoch Eocene Miocene

PliocenePleistocene

Oligocene

PlesiadapiformsFirst Primates Evolve

Prosimians thrive1st AnthropoidsEvolve

Monkeys &1st primatesin South America

HominoidsHumans

Hominins

1.8 mya

Cenozoic Era: 65 my - present: 7 Epochs

Holoocene

10 kya

Continental drift is important part of human history because it changed global climates

25C = 77 F10C = 50 F

Temperatures have declined steeply from Eocene to presentHuge fluctuations in last 5 my

The Cenozoic: Paleocene• Paleocene wet & warm

Radiation of mammal taxa with some primate-like traits

Plesiadapiforms – not quite yet primates thrive Europe & North America Primate-like molars Ankles for climbing trees

Purgatorius

Dryomomys

The Cenozoic: Eocene

• Eocene wetter & warmer Tropical forests SA isolated from NA & Europe =

new species First true primates Prosimian-like traits Two families in North America &

Europe Adapidae

– Lemur-like prosimians Omomyidae

– Tarsier-like prosimians• Mass extinction at end of Eocene• First Anthropoids evolve

Smilodectes

The Cenozoic: Oligocene

• Oligocene getting colder & drier more seasonal variation Mostly modern continent positions

South America still separate Cold water currents cooling earth

Africa & SA tropical forests remain Tropics receding in other areas

Age of the Anthropoid (monkeys) Parapithecidae (Apidium) Proliopithecidae (Aegypotopithecus)

First platyrrhines in South America! First Hominoids (apes) evolve

Aegypotopithecus

The Cenozoic: Miocene

• Miocene warm & moist at beginning Got colder & drier Forests retreating = open woodland habitat Himalayas form = block warm cold air currents Rift valley forms = rain shadow & dry savannah

The Cenozoic: Miocene

• Miocene warm & moist at beginning Golden age of the Hominoids (apes) (early Miocene)

Great diversity of species Fruit diet specialization Some arboreal quadrupeds, some terrestrial

quadrupeds, suspensory adaptations later

• Late Miocene getting drier & colder Ape shift to knuckle-walking adaptations Ape species retreat to remaining tropics Mass extinction of apes at end of Miocene First hominins evolved (late Miocene)

Proconsul

Ardipithecus

Proconsul

• Lived in African rainforest• DF: 2.1.2.3• Terrestrial quadruped• Large (165-220 lbs)• No tail• Sexually dimorphic• Frugivorous

Dryopithecus

• European Radiation

• Brachiator, also terrestrial quadruped on palms

• DF: 2.1.2.3

• Frugivorous & Folivorous Thin enamel, low

rounded cusps on molars

• Small canines

Sivapithecus

• Asian ancestor of Orangutans• Concave face• Flared zygomatic arches• Large (70-150 lbs)• DF: 2.1.2.3• Large canines• Heavy molars - tough foods

Others ate more fruit• Some species terrestrial, others

arboreal Suspensory adaptations

The distribution of primate species shifted during Miocene

5 mya23 mya

• Monkeys are more r-selected than apes

• reproduce faster

• respond quickly to environmental changes

• apes didn’t adapt to changes, stayed in tropical forest niches

The Cenozoic: Age of the Hominins• Pliocene begins frequent temperature fluctuations

Hominins diversify Australopithecines & Paranthropines

• Pleistocene: extreme temperature fluctuations Genus Homo appears 1.8 mya

Primate Evolution: A summary

• Mesozoic: Cretaceous: Placental mammals & Angiosperms • Cenozoic

Paleocene: Plesiadapiforms Eocene: Age of Prosimians Oligocene: Age of Anthropoids + first Hominoids (apes) Miocene: Hominoids expand + first Hominins (7mya) Pliocene: Hominins diversify (5-1.8 mya) Pleistocene: First genus Homo (1.8 mya)

200,000 ya: First Homo sapiens Holocene: 10,000 ya: History

Classifying species into taxa

• Linnaeus – classification based on

physical similarity Genus species, e.g. Homo sapiens

• Nested hierearchies of similarity due

to common descent (Darwin)

VERTEBRATES

Birds Mammals

Sparrow Flamingo Lion Squirrel

Phylogeny

• Phylogeny = evolutionary relationships among groups of species

• When one species splits into 2 Share some ancestral traits Differ in some derived traits

• Differences accumulate within evolutionary lineages over time

Homologous traits: shared phylogenetic history

Similar underlying structures can be modified

for very different functions

Bats fly

Dugongs swim

Moles digAll share the same

Basic limb structure because share common ancestor

Analogous traits: different phylogenetic history

Different structures can be used for similar functions

• Bats and birds fly

• Bat wing is modified from bones of hand

• Bird wings are modified from bones of forelimb

Convergent Evolution: leads to analogous traits

Adaptation to solve similar ecological problems

(Smilodon): (Thylacosmilus):placental mammal marsupial mammal

Both animals adapted to catch large prey with teeth and claws.

Adaptation to solve similar problems

(Smilodon): (Thylacosmilus): placental mammal marsupial mammal

Convergent Evolution: leads to analogous traits

Where do we fit in? Homo sapiens• Kingdom: Animal• Phylum: Chordata• Class: Mammalia• Order: Primates

• Suborder: Anthropoidea• Infraorder: Catarrhini• Superfamily: Hominoidea• Family: Hominidae• Subfamily: Homininae• Tribe: Hominini• Genus: Homo• Species: sapiens