Evolutionary history

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Evolutionary History
E l ti
Hi t

AP Biology Rapid Learning Series
Wayne Huang, PhD
Andrew Graham, PhD
Elizabeth James, PhD
Casandra Rauser, PhD
Jessica Habashi, PhD
Sara Olson, PhD
Jessica Barnes, PhD

© Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com

www.RapidLearningCenter.com/
© Rapid Learning Inc. All rights reserved.

1


Learning Objectives
By completing this tutorial, you will learn about:
Evolutionary theory and the
origin of life.
i i
f lif
How Geology & Biology
effect one another.
An understanding of today’s
evolving world.
The evolution of modern
humans.

3/55

Concept Map

Time

Origin of
Earth

Fossil Record
Human
Evolution

Origin of
Life

Proto-life
(RNA)

Evolution of
5 Kingdoms

4/55


2


Origin of Life on Earth
When did “evolution begin”?
Darwin and the “Origin of Life” theory.
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 from
that long ago!

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.
6/55


3


Darwin & the Origin of Life
In the Origin of the Species, I
note that there are few fossils
that date back to the beginning
of the earth.

Because of a lack of fossil
records dating that far back I
cannot speculate on when or
how life began.
7/55

Darwin

Search for Earliest Records of Life
What would the earliest forms of life look like and fossilize like?

Initial organisms
g
were likely single
celled & therefore
microscopic.

Such fossils
are not found
in typical rock
/ shale.

Chain of cyanobacteria.
Fossil evidence date to:
3.8 billion years ago.

Formed from fine
sediment: minerals
flow into mass of
microorganisms
Stromatolite rocks

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4


Oldest Fossils
Zeroing in on the inception of life
Oldest stromatolite containing microorganisms
determined to be ~ 3.5 billion years old.
d t
i dt b
3 5 billi
ld
Consists of photosynthetic bacteria.

Precambrian Stromolite
9/55

Cyanobacteria were dominant
for at least 2 billion years,
some forms still exist today.

How & When Did Life Start


5


Proto Life
Beyond assuming that life just
“appeared”, how do biologists explain
its emergence from the prebiotic world
four billion years ago?

11/55

Steps to Life

If we assume life did not result from a seeding event
from an asteroid or other interstellar body, then:
body
Life had to have developed from inorganic
materials.
Problem: Spontaneous animation (= life from nonlife) does not happen today. So, how could this
be?

12/55


6


Miller Experiment
Earth’s early atmosphere

spontaneous animation?

Early earth atmosphere = Reducing as opposed to
g
p
y
oxidizing atmosphere of today
Miller experiment created a model system of early
earth using only inorganic molecules; over time
organic chemicals (nucleic acids, amino acids…)

13/55

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

Proto-Life:

Organic compounds
units

polymers of repeating

Lipids & others can and do organize into spheres
based on inherent properties.
Lipid spheres can encapsulate organic molecules.

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7


Proto Life and RNA
Encapsulated organic molecules such as RNA can:
Self-replicate, are autocatalytic, can act as
rudimentary templates for protein synthesis
di
t
t
l t f
t i
th i
Compete for scarce resources such as RNA
monomers
natural selection of “fittest” RNA
Competition
molecule
reproduction of that RNA molecule

15/55

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.

Could this have
been the
beginning of the
ancient cell?
We don’t really
know for sure.
16/55


8


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 exo /
endoskeletons favor
fossilization those without
less likely to be fossilized
and found.

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

This requires new methods of
detecting earliest forms of life.
First life forms per fossil
record are prokaryotic
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Prokaryotic Evolution


9


Prokaryote Preview
Prokaryotes, also
known as bacteria.

1. Prokaryotic
1 P k
ti
description
2. Key adaptations
in Evolution
3. Prokaryotic
Relationships
4. Geological &
Biological
relationships.

19/55

Prokaryotes
80% of the history
of life on earth
concerns
prokaryotes.

Prokayotes evolved
about 2 billion years ago.
It is estimated that there
are about 10 000 species
10,000
of prokaryotes belonging
to the Kingdom Monera.

Sandstone: life in extreme
environments. Blue bands are layers
of algae, fungi, and bacteria know as
cryptoendolithic organisms.
20/55


10


Prokaryotes Evolutionary Adaptation
Most Prokaryotic
adaptations revolve
around metabolic
capacities as opposed to
phenotypic changes.

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

Each new
metabolic capacity
enabled bacteria to
bl d b t i t
occupy new niches

21/55

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

First Life Forms

Archaebacteria:
Extremophiles
p
(live in extreme
conditions),
likely most
ancient
recordable
forms of life

Archaebacteria
Eubacteria

Eubacteria:
Ancestors to
almost all
contemporar
y bacteria
today

22/55


11


Eubacteria
Eubacteria have
y
many
characteristics in
common with
Domain Archaea.
Archaea and
Eubacteria together
are known as the
prokaryotes.

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

Fusobacterium
Proteobacteria is
a major group of
eubacteria and
has several
subdivisions.
23/55

Evolution of Photosynthesis
02 atmosphere shifted from
a reducing environment to
an oxidizing atmosphere
atmosphere.
Life had to adapt or
go extinct (most
went extinct).

The evolution of
photosynthesis is
the most important
event occurring
after life evolved.

Niches were solidified.
That is species became
anaerobes or aerobes.

24/55


12


Protist Evolution

The First Eukaryotes

Protists Preview
Protists are
the first
eukaryotes.
eukaryotes

Protists are diverse
and made up of those
eukaryotes that cannot
be classed into any of
the other kingdoms as
fungi, animals or
plants.

Amoeba
Ammonia tepida
26/55


13


Major Groups of Protists
Protists have been
traditionally divided into
g
groups based on their
p
morphology, and ecology
and similarities to higher
kingdoms.

So they have been thought of as: plant
like, fungus like or animal like.
This has been replaced by
phylogenetic classification but is
useful for describing protists.

Giardia

Examples of protists
include: amoebas, algae
and slime molds.

27/55

Primary Adaptations of Protists
Primary evolutionary adaptations of
protists include:
Endosymbiosis: which evolved into
eukaryotic organelles
y
g
Colony behavior: which let to
multicellular organisms.

28/55


14


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

Much evidence comparing
similarities of mitochondria to
prokaryotes supports this idea.

29/55

Plant Evolution


15


Plant Preview
Chloroplasts in eukaryotic plants
evolved from an endosymbiotic
relationship between
cyanobacteria and another
y
prokaryote. This evolved to a
photosynthesizing eukaryotic
organism in water environments.
Plant evolution
involves the
adaptation of plants
suited to live on land
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.

31/55

Plants From Protist Algae
All plants are multicellular eukaryotes with the capacity
for photosynthesis.
Aquatic protists
terrestrial plants (i.e., moss)
species adaptations including:
i
d t ti
i l di
Cuticles to prevent drying
System of specialized cells
vascular conduits
more efficient water transport
new niches further
away from water sources

Moss

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

32/55


16


Plants Reproductive Adaptations
Seeds
Early terrestrial plants such as ferns, were seedless
Gametes were dispersed via spores
One reproductive adaptation
Seeds carry plant gametes further from parents
increased opportunities for uncontested resources
Seed adaptation
Gymnosperms
Ferns

speciation event
Naked
Seed

Gymnosperms

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Leaf, Flower Adaptations
Flowers
Modified Leaves
Flowering plants
more efficient
seed dispersal and pollination secondary to pollinators
d di
l d
lli ti
d
t
lli t
Flowering plants = speciation event

Angiosperms

Angiosperms

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17


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 forms
forms.

36/55


18


Fungi Overview
Fungi is evolved from protists by unknown mechanisms.
Fungi traits
include

Branched
hyphae

Cell
wall
of
chitin

Dual
Reproduction
modes

Digest food
outside
body
absorption

37/55

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.

Fungi are very important in
the environment, for
nutrition and can cause
disease.
38/55


Puff ball mushroom

19


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”.

40/55


20


Animal Phylogeny
Ancestral
Protists

Eumetazoa

Parazoa
Sponges

Radiata

Bilateria

Pseudocoelomate
Nematodes

Flatworms

Jellyfish

Coelomates

Dueterostome
Echinoderms

Cnidaria

Acoelomates

Protostomes
Mollusks
Annelids
Arthropods

Chordates

Invertebrates

Vertebrates

41/55

Major Phyla & Relationships
Taxonomic relationships based on comparative
anatomy & embryology
Ancestral
Protists
Eumetazoa
Radiata
Bilateria

Major change in body plan:
Radial Vs Bilateral

All members in this group
have “radial” cleavage
patterns in embryogenesis
All members have:
-Notochord, nerve cord,
pharyngeal slits, post anal
tail

Coelomates
Dueterostomes
D t
t
Chordates
Vertebrates

Inner body
cavity tube
lined
completely by
mesoderm

All members have back bone
/ vertebral column

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21


Major Morphologic Changes
How have the major changes in body plan and defining major
taxonomic groups developed?
One major cause is paedogenesis
paedogenesis.

Paedogenesis: Larvae
reaches reproductive
maturity before
reaching adulthood
maintenance of larval
life cycle and
morphology
major
change in body plan

Hypothesis:
yp
paedogenesis of early
larval chordates
maintenance of motile
organism with chordate
features, favored by
selection pressure.

43/55

Paedogenesis & Urochordates
Normal urochordates mature into
sedentary, amotile life forms, keeping
only 1 of 4 chordate traits.
Their larvae are motile, & possess all 4
traits of chordates.
Hypothesis: Paedogenesis of early
larval urochordates led to
maintenance of motile organism
with all chordate features.

Progenetic
organisms are
able to reproduce
in the larval form.
44/55


22


Vertebrate Evolution Paedogenesis
Selection acts on the
paedogenic larval
urochordates resulting
in modifications of
chordate traits
traits.

45/55

Sea Peach
Urochordate

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
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,
g
not the least of which being the dinosaur extinction.
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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23


Geological Effects on Morphology

The first known
super continent
= Rodinia ~ 1000
– 750 million
years ago

Geographic
isolation of
populations
isolated gene
pools
new
environments
new adaptations
47/55

Such events represent
the interplay between
geological and
evolutionary events
g
p
biological speciation
Land mass shifts

Super continent
Pangaea forms and
breaks up
breaks-up ~ 300 – 180
million years ago

Vertebrate Subphylum
Classes of vertebrate subphylum include:
Fishes
Amphibians
Reptiles
Mammals
Avians
As it turns out, the order here is the general chronology
of the evolutionary record
record.
Each class being derived from the one above, with the
exception of avians and reptiles both being derived from
reptiles.
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24


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”.
Primate

There are at
least 14 major
orders of
mammals.

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

49/55

Primate Evolution
Old world
monkeys

New World
Monkeys

Prosimians

Gorillas

Orangutans

Gibbons

Hands & Feet of Primates

Chimpanzees
50/55


Humans

25


Lineage of Modern Humans
Dashed lineage
represents debate over
evolutionary chronology
Some of these genus /
species may have coexisted.

Ramapithicus

Homo habilis : “handy man”
Likely used simple stone tools

Australopithecus afarensis :
Walked erect
Australopithecus africanus :
Hominid

Homo erectus : “upright
man” 2x l
” 2 larger brain then
b i th
earliest predecessor
Homo sapiens
Modern Humans: Brain size 3x
Neanderthals: Brain size larger
larger then Australopithecus,
then modern humans but extinct
oldest fossil ~ 90,000 years old
51/55

Question: Review
____ first appeared on earth
around 3.55 billion years ago.

Life
___________

Fungi are important because
F
i
i
t tb
they _____ nutrients.

Recycle
___________

Eubacteria and Archae
together make up of this
doman.

Prokaryotes
___________

Lipids can spontaneously
p
p
y
form micelles and _____
organic compounds.

Encapsulate
___________

_____ are the first
eukaryotes.

Protists
___________

52/55


26


Learning Summary
Brief
Evolutionary
History of
other
kingdoms

Origin of Life
according to
Fossils

How Life
started

Vertebrate &
Human
Evolution

Prokaryotic
Evolution

53/55

Congratulations
You have successfully completed
the core tutorial

Evolutionary History

54/55


27


Chemistry :: Biology :: Physics :: Math

What’s N t
Wh t’ Next …

Step 1: Concepts – Core Tutorial (Just Completed)
Step 2: Practice – Interactive Problem Drill
Step 3: Recap – Super Review Cheat Sheet

Go for it!

55/55

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Evolutionary history

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