Evolutionary history

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E l ti Hi tEvolutionary History

AP Biology Rapid Learning Series

Rapid Learning Centerwww.RapidLearningCenter.com/

© Rapid Learning Inc. All rights reserved.

AP Biology Rapid Learning SeriesWayne Huang, PhD

Andrew Graham, PhDElizabeth James, PhD

Casandra Rauser, PhD Jessica Habashi, PhD

Sara Olson, PhDJessica Barnes, PhD



Learning Objectives

Evolutionary theory and the i i f lif

By completing this tutorial, you will learn about:

origin of life.

How Geology & Biology effect one another.

An understanding of today’s evolving world.

The evolution of modern

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The evolution of modern humans.

Concept Map

Origin of Earth

Time

Human Evolution

Fossil Record

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Origin of Life

Evolution

Proto-life(RNA)

Evolution of 5 Kingdoms



Origin of Life on Earth

When did “evolution begin”?Darwin and the “Origin of Life” theoryDarwin and the “Origin of Life” theory.Fossil record.

Beginning of Evolutionary History

Earth was formed about 4.55 billion

years ago.

Advanced forms of life on earth existed at least 3.55 billion

years ago. Imprints of bacteria have been found in rock fromhave been found in rock from

that long ago!

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Basic structure of earth. Continents float on crust or

tectonic plates.Mantle: semi solid layer

between the crust and the core, which is made up of

heavy metals.



Darwin & the Origin of LifeIn the Origin of the Species, I note that there are few fossils

that date back to the beginning of the earth.

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Because of a lack of fossil records dating that far back I cannot speculate on when or

how life began.

What would the earliest forms of life look like and fossilize like?

Search for Earliest Records of Life

Initial organisms gwere likely single celled & therefore microscopic. Such fossils

are not found in typical rock / shale. Formed from fine

sediment: minerals flow into mass of

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flow into mass of microorganisms Stromatolite rocks

Chain of cyanobacteria.Fossil evidence date to:

3.8 billion years ago.



Oldest Fossils

Oldest stromatolite containing microorganisms d t i d t b 3 5 billi ld

Zeroing in on the inception of life

determined to be ~ 3.5 billion years old.

Consists of photosynthetic bacteria.

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Precambrian Stromolite Cyanobacteria were dominant for at least 2 billion years,

some forms still exist today.

How & When Did Life Start



Proto LifeBeyond assuming that life just

“appeared”, how do biologists explain its emergence from the prebiotic world

four billion years ago?

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Steps to Life

If we assume life did not result from a seeding event from an asteroid or other interstellar body then:from an asteroid or other interstellar body, then:

Life had to have developed from inorganic materials.

Problem: Spontaneous animation (= life from non-life) does not happen today. So, how could this be?

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Miller Experiment

Early earth atmosphere = Reducing as opposed to oxidizing atmosphere of today

Earth’s early atmosphere spontaneous animation?

g p y

Miller experiment created a model system of early earth using only inorganic molecules; over time organic chemicals (nucleic acids, amino acids…)

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Prebiotic Conditions: Proto-life

Basic sequence Proto-Life:

With pre-biotic conditions set, Proto-life may occur according to many hypotheses:

Organic compounds polymers of repeating units

Lipids & others can and do organize into spheres based on inherent properties.

Lipid spheres can encapsulate organic molecules.

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Proto Life and RNA

Encapsulated organic molecules such as RNA can:

Self-replicate, are autocatalytic, can act as di t t l t f t i th irudimentary templates for protein synthesis

Compete for scarce resources such as RNA monomers

Competition natural selection of “fittest” RNA molecule reproduction of that RNA molecule

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Proto Life Evolves to Life ?Lipids can spontaneously form

bilayers (like a cell’s membrane).

These lipid bilayers (liposomes) can encapsulate organic polymers like RNA, sugars, proteins and fats.

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Could this have been the

beginning of the ancient cell?

We don’t really know for sure.



Where is Darwin’s Evidence ?Evidence of earliest life via fossil record may not be possible.

Ability of fossils to record history limited

Organisms with cell membranes but without cell walls (for example mycoplasma) may not fossilize.

Organisms with exo / endoskeletons favor fossilization those without

less likely to be fossilized and found.

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This requires new methods of detecting earliest forms of life.

First life forms per fossil record are prokaryotic

Prokaryotic Evolution



Prokaryote Preview

1 P k ti

Prokaryotes, also known as bacteria.

1. Prokaryotic description

2. Key adaptations in Evolution

3. Prokaryotic Relationships

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4. Geological & Biological relationships.

Prokaryotes

Prokayotes evolved about 2 billion years ago. It is estimated that there are about 10 000 species

80% of the history of life on earth

concerns are about 10,000 species of prokaryotes belonging to the Kingdom Monera.

prokaryotes.

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Sandstone: life in extreme environments. Blue bands are layers of algae, fungi, and bacteria know as cryptoendolithic organisms.



Prokaryotes Evolutionary Adaptation

Most Prokaryotic adaptations revolve around metabolic

capacities as opposed to

Major metabolic adaptations include: Glycolytic pathway, Oxidative Phosphorylation, Photosynthetic enzymes.

phenotypic changes.y y

Each new metabolic capacity

bl d b t i t

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enabled bacteria to occupy new niches

Prokaryotic Relationships

Working backward from extinct species, most important speciation event is between archaebacteria & eubacteria.

First Life Forms

Archaebacteria: Extremophiles

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ArchaebacteriaArchaebacteria

Eubacteria

p(live in extreme

conditions), likely most

ancient recordable

forms of life

Eubacteria: Ancestors to

almost all contemporar

y bacteria today



Eubacteria

Eubacteria is one of the three clades into which biological life on earth

Eubacteria have many

is divided.y

characteristics in common with

Domain Archaea. Archaea and

Eubacteria together are known as the

prokaryotes.

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Proteobacteria is a major group of eubacteria and

has several subdivisions.

Fusobacterium

Evolution of Photosynthesis

02 atmosphere shifted from a reducing environment to an oxidizing atmospherean oxidizing atmosphere.

Life had to adapt or go extinct (most

went extinct).

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The evolution of photosynthesis is

the most important event occurring

after life evolved.Niches were solidified. That is species became anaerobes or aerobes.



Protist Evolution

The First Eukaryotes

Protists Preview

Protists are the first

eukaryotesProtists are diverse

and made up of thoseeukaryotes. and made up of those eukaryotes that cannot be classed into any of the other kingdoms as

fungi, animals or plants.

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AmoebaAmmonia tepida



Major Groups of Protists

Protists have been traditionally divided into groups based on their

So they have been thought of as: plant like, fungus like or animal like.

g pmorphology, and ecology and similarities to higher

kingdoms.

This has been replaced by phylogenetic classification but is

useful for describing protists.

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Examples of protists include: amoebas, algae

and slime molds.

Giardia

Primary Adaptations of Protists

Primary evolutionary adaptations of protists include:

Endosymbiosis: which evolved into eukaryotic organellesy g

Colony behavior: which let to multicellular organisms.

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Endosymbiotic Hypothesis

Endosymbiotic hypothesis: Attempts

~ 2100 million years ago, protists arose in a unique way.

hypothesis: Attempts to account for the major evolutionary

leap from prokaryotes to protists, the first

eukaryotes.

In a nutshell, hypothesis proposes a larger prokaryote ingested a smaller

prokaryote organelles such as mitochondria and chloroplasts.

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Much evidence comparing similarities of mitochondria to

prokaryotes supports this idea.

Plant Evolution



Plant Preview

Chloroplasts in eukaryotic plants evolved from an endosymbiotic

relationship between cyanobacteria and another

Plant evolution involves the

adaptation of plants suited to live on land

yprokaryote. This evolved to a photosynthesizing eukaryotic

organism in water environments.

Early plants were

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suited to live on land. This led to the

greening of land masses and plant

diversification.

Early plants were unicellular or filamentous.

It is estimated the first plants evolved around 3000 million

years ago.

Plants From Protist Algae

Aquatic protists terrestrial plants (i.e., moss)i d t ti i l di

All plants are multicellular eukaryotes with the capacity for photosynthesis.

species adaptations including:

Cuticles to prevent drying

System of specialized cells vascular conduits more efficient water transport new niches further away from water sources

The vascular adaptation pivotal speciation

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The vascular adaptation pivotal speciation event dividing vascular & nonvascular plant life.Moss



Plants Reproductive Adaptations

Early terrestrial plants such as ferns, were seedless

Seeds

Gametes were dispersed via spores

One reproductive adaptation

Seeds carry plant gametes further from parents increased opportunities for uncontested resources

Seed adaptation speciation event

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Gymnosperms Naked Seed

Ferns Gymnosperms

Leaf, Flower Adaptations

Modified Leaves Flowering plants more efficient d di l d lli ti d t lli t

Flowers

seed dispersal and pollination secondary to pollinators

Flowering plants = speciation event Angiosperms

Angiosperms

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Fungi Evolution

Fungi Preview

Fungi are a group of organisms ranked as a kingdom within the Domain Eukaryota. These include mushrooms, molds, yeast and other

microscopic formsmicroscopic forms.

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Fungi OverviewFungi is evolved from protists by unknown mechanisms.

Fungi traits includeinclude

Branched hyphae

Cell wall of chitin

Dual Reproduction modes

Digest food outside body absorption

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Fungi Importance

Medically, it causes diseases like histoplasmosis (pneumonia)

and candidiasis (urinary tract infections).

Some fungi are extremely poisonous for which there

is no antitoxin.

Fungi are important in the environment because they decompose organic matter so it may be recycled and used by other organisms.

infections).

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Fungi are very important in the environment, for

nutrition and can cause disease.



Animal Evolution

Vertebrate Evolution

Animal Preview

Animals are thought to have evolved from

flagellated eukaryotes.

First animal fossils appear around 575 million years ago and are called Ediacaran. They may or may not

belong to the animal kingdom.

Most known animal phyla appear almost simultaneously about 542 million years

ago during the “Cabrian explosion”.

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Animal PhylogenyAncestral Protists

Eumetazoa

Bilateria

Nematodes

Parazoa

RadiataSponges

Cnidaria

Jellyfish

Acoelomates

CoelomatesFlatworms

Pseudocoelomate

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Coelomates

ProtostomesDueterostome

ChordatesEchinoderms

VertebratesInvertebrates

MollusksAnnelids

Arthropods

Major Phyla & RelationshipsTaxonomic relationships based on comparative anatomy & embryology Ancestral

Protists

Eumetazoa

Bilateria RadiataMajor change in body plan: Radial Vs Bilateral

Coelomates

D t t

All members in this group have “radial” cleavage patterns in embryogenesis

Inner body cavity tube lined

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Dueterostomes

Chordates

Vertebrates

patterns in embryogenesis

All members have:

-Notochord, nerve cord, pharyngeal slits, post anal tail

All members have back bone / vertebral column

completely by mesoderm



How have the major changes in body plan and defining major taxonomic groups developed?

Major Morphologic Changes

One major cause is paedogenesis

Paedogenesis: Larvae reaches reproductive

maturity before reaching adulthoodmaintenance of larval

life cycle and Hypothesis:

One major cause is paedogenesis.

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life cycle and morphology major change in body plan

yppaedogenesis of early

larval chordates maintenance of motile

organism with chordate features, favored by selection pressure.

Paedogenesis & Urochordates

Normal urochordates mature into sedentary, amotile life forms, keeping

only 1 of 4 chordate traits.

Hypothesis: Paedogenesis of early larval urochordates led to

maintenance of motile organism with all chordate features.

Their larvae are motile, & possess all 4 traits of chordates.

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Progenetic organisms are

able to reproduce in the larval form.



Vertebrate Evolution PaedogenesisSelection acts on the

paedogenic larval urochordates resulting

in modifications of chordate traitschordate traits. Traits modified include:

1. Pharyngeal slits for terrestrial gas exchange.

2. Hollow nerve cord for specialized sensory organs, concentrated in the head region.

3. Notochord for primitive axial support and that is eventually

45/55Sea Peach

Urochordate

support and that is eventually replaced by the vertebral column.

4. Finally selection for more powerful swimming apparatus.

trochophore larva

Morphologic Evolution

Extinction events:There have been several in the Triassic period alone, not the least of which being the dinosaur extinction.g

Some estimate that 90% of all animal species were lost during this time period.

What caused this extinction is still up for debate.

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Geological Effects on MorphologySuch events represent the interplay between

geological and evolutionary events biological speciation

Land mass shifts

The first known super continent = Rodinia ~ 1000

– 750 million years ago

Super continent Pangaea forms and

breaks-up ~ 300 – 180

g p

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breaks up 300 180 million years agoGeographic

isolation of populations isolated gene pools new

environments new adaptations

Vertebrate Subphylum

Fishes

Amphibians

Classes of vertebrate subphylum include:

Amphibians

Reptiles

Mammals

Avians

As it turns out, the order here is the general chronology of the evolutionary record

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of the evolutionary record.

Each class being derived from the one above, with the exception of avians and reptiles both being derived from reptiles.



Reptiles -> Mammalian Class

Mammals speciated from reptiles during the Triassic period.

During this period many new “Orders” of mammal

evolved. Humans are in the order “Primate”

There are at least 14 major

orders of mammals.

order Primate .

Early mammals were small, insectivorous, nocturnal, hairy and warm blooded.

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Primate EvolutionOld world monkeys

New World Monkeys

Gorillas OrangutansGibbons

Prosimians

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Hands & Feet of Primates



Lineage of Modern HumansDashed lineage

represents debate over evolutionary chronology Some of these genus / Australopithecus afarensis :

Ramapithicus

species may have co-existed.

Walked erect

Australopithecus africanus : HominidHomo habilis : “handy man”

Likely used simple stone tools

Homo erectus : “upright ” 2 l b i th

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Homo sapiens

man” 2x larger brain then earliest predecessor

Modern Humans: Brain size 3x larger then Australopithecus,

oldest fossil ~ 90,000 years oldNeanderthals: Brain size larger

then modern humans but extinct

Question: Review

____ first appeared on earth around 3.55 billion years ago. ___________Life

F i i t t b ___________

___________

Recycle

Prokaryotes

Fungi are important because they _____ nutrients.

Lipids can spontaneously

Eubacteria and Archae together make up of this doman.

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___________Encapsulatep p y

form micelles and _____ organic compounds.

_____ are the first eukaryotes. ___________Protists



Brief Evolutionary

Brief Evolutionary Origin of Life Origin of Life Vertebrate & Vertebrate &

Learning Summary

History of other

kingdoms

History of other

kingdoms

according to Fossils

according to Fossils

Human Evolution

Human Evolution

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How Life started

How Life started

Congratulations

You have successfully completed the core tutorial

Evolutionary History

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