history of life on earth and classification.pptfaculty.sdmiramar.edu/bhaidar/bio 107...

History of life on Earth & Classification of living organisms

CenozoicLast 0.5 bilion years

HumansConditions on early

Earth made the origin of life possibleColonization

of landAnimals

Origin of solarsystem andEarth

origin of life possible

A recipe for life

1 4

pRaw materials

+ Suitable

Proterozoiceon

Archaeaneon

2 3

Suitable environment

+

Single‐celledeukaryotes Atmospheric

Multicellulareukaryotes

Prokaryotes

Energy sources

eukaryotes Atmosphericoxygen

S h l d lif fCenozoic

Last 0.5 bilion years

Chemical conditions Physical conditions

Stages that led to life formsHumans

y

Abiotic synthesis of monomers

Stage 1

Colonizationof land

Animals

Formation of polymersStage 21 4

Packaging of polymers into protobionts

Stage 3

Proterozoiceon

Archaeaneon

1

2 3

4

Self-replicationStage 4Single‐celledA h i


Prokaryotes


Stage 1: The abiotic synthesis of monomersStanley Miller’s experiments produced abundant aminoStanley Miller s experiments produced abundant amino acids and other organic molecules

H2O vapor and compounds released from volcanic eruptions, including N2 and its oxides, CO2,N2 and its oxides, CO2, CH4, NH3, H2, and H2S

Stage 2: The formation of polymers– Monomers could have combined to form organic

polymers

– Clay as substratum for polymerization?

H

OH HOH

U li k dSh t l

OH H

U li k dSh t l

Synthesis

Unlinked monomer

Dehydration eactio

Short polymer Unlinked monomer

Dehydration reaction

Short polymer

H2O

H OH

reaction

H OH

Longer polymer

Stage 3: Packaging of polymers into protobionts– Polymers could have aggregated into complex,

organized, cell‐like structures

What characteristics do cells and protobionts share?– Structural organization– Structural organization

– Simple reproduction

– Simple metabolism Glucose‐phosphatep

– Simple homeostasis

Gl h h t

Phosphatase

Glucose‐phosphate

PhosphateM lt

Amylase

Starch

Maltose

Maltose

(b) Simple metabolismMaltose

Stage 4: Self‐replication– RNA : first genetic material and as the first enzymesRNA : first genetic material and as the first enzymes– The first genes made of RNA that replicated without

protein supportRNA l ib h i d i hi– RNA catalysts or ribozymesmay have assisted in this process.

RNA world!o d

Cenozoic

Humans

Last 0.5 bilionyears

Colonizationof landAnimals


Prokaryotes lived alone on Earth for 1.5 billion years Multicellular

Proterozoiceon

Archaeaneon

1

2 3

4

1.5 billion years– Transformed Earth’s biosphere Single‐celled


eukaryotesProkaryotes

• Metabolic pathways evolved within prokaryotesCellular respiration arose in prokaryotes using oxygen to– Cellular respiration arose in prokaryotes, using oxygen to harvest energy from organic molecules

CenozoicLast 0.5 bilion years

Humans

Colonizationof land

AnimalsOrigin of solarsystem andEarth

Key events in life’s history: Th i i f i l

1 4

‐ The origins of single‐celled and multi‐celled organisms

Proterozoiceon

Archaeaneon

2 3

organisms ‐ the colonization of land

Single‐celled


Prokaryotes

2 3

geukaryotes Atmospheric

oxygen

• Origin of the eukaryotic cells:Cenozoic

Humans


A community of prokaryotes,

when small prokaryotes capable



of aerobic respiration or photosynthesis

began living in larger cellsOldest fossils of e kar otes are 2 1 billion ears old

Multicellular

Proterozoiceon

Archaeaneon

1

2 3

4

– Oldest fossils of eukaryotes are 2.1 billion years old

M lti ll l f b t 1 5 billi

Single‐celledeukaryotes Atmospheric

oxygen

eukaryotesProkaryotes

• Multi‐cellular forms arose about 1.5 billion years ago– The descendents of these forms include a variety of algae,

plants fungi animalsplants, fungi, animals– The oldest known fossils were small algae, living 1.2 billion years ago

• The diversity of animal forms increased

dd l d d ti ll b t

Cenozoic

Humans


suddenly and dramatically about

535–525 million years ago in the

Cambrian explosion



Cambrian explosion‐ Tetrapods & Arthropods are the most

widespread and diverse land animalsProterozoic

eonArchaean

eon

1

2 3

4

‐ Human lineage diverged from apes

7–6 million years ago Single‐celledeukaryotes Atmospheric

oxygen


Prokaryotes

2 3

• Fungi and plants colonized land together 500 million years ago‐ Roots of most plants have fungal associates that exchange water and

i l f iminerals for nutrients

Forces shaping Macroevolution and Earth’s iHistory

The fossil record documents the main events in theThe fossil record documents the main events in the history of life

– Continental drift

– Mass extinctions were followed by diversificationMass extinctions were followed by diversification of life‐forms

Continental drift is the slow, continuous movement of Earth’s crustal plates on the hot mantlep– Crustal plates carrying continents and seafloors float on a

liquid mantle

Eurasian PlateNorthA i

IndianPlate

AmericanPlate

Pacific

ArabianPlate

Australian

Splitdeveloping

SouthAmericanPlate

NazcaPlate

PacificPlate African

Plate

Ed f l b i h d d f

Antarctic Plate

Plate

Edge of one plate being pushed over edge ofneighboring plate (zones of violent geologic events)

Figure 15.3A

• Important geologic processes occur at plate boundariesSliding plates are earthquake zones– Sliding plates are earthquake zones

– Colliding plates form mountains

San Andreas Fault

NorthAmericanPlate

San FranciscoSanta Cruz

PacificPlate

Los Angeles

California

Figure 15.4A, B

The formation of Pangaea00

Ceno

zoic

E i

65

years ago C Eurasia

AfricaSouth America

India

Antarctica

Continental drift changes the land masses on earth and impact all

135

illions of y

ozoic

Laurasiaon earth and impact all forms of life:

altering habitats and M

Mesoaltering habitats and

triggered extinctions

245

eozoic

Figure 15.3B

Pale

Mass extinctions destroy large numbers of species

– Extinction is the fate of all species and most lineages

– The history of life on Earth reflects a steady background extinction rate with episodes of mass extinctionextinction

– Over the last 600 million years, five mass extinctions have occurred in which 50% or more of the Earth’shave occurred in which 50% or more of the Earth s species went extinct

Permian extinction– 96% of shallow water marine species died in the Permian

extinction

– Possible cause? E t l i i Sib i l d CO d l b l li t– Extreme vulcanism in Siberia released CO2, warmed global climate, slowed mixing of ocean water, and reduced O2 availability in the ocean

Cretaceous extinction– 50% of marine species and many terrestrial lineages went– 50% of marine species and many terrestrial lineages went

extinct 65 million years ago– All dinosaurs (except birds) went extinct

– Likely cause was a large asteroid that struck the Earth, blocking light and disrupting the global climate

NorthAmericaAmerica

Chicxulubcrater

YucatánPeninsula

•

YucatánPeninsula

Biodiversity and ClassificationBiodiversity and Classification

• Taxonomy is the field of study of biodiversity and y y yits classification– Taxonomists assign a binomial consisting of a genus and species name to each speciesand species name, to each species

• Phylogeny is the study of the evolutionary history of a i f i b d lspecies or group of species‐ based on structural

homologies in fossils and living organisms

• Systematics connects classification with evolutionary history

Species:Felis catus

Genus: Felis

Family: Felidae• Species

• Genus

Cl M li

Order: Carnivora• Genus

• Family

• OrderClass: Mammalia

Phylum: Chordata

• Class

• Phylum y

Kingdom: Animalia

• Kingdom

• Domain

Bacteria Domain: Eukarya Archaea

A phylogenetic TreeA phylogenetic Tree

A hypothesis ofA hypothesis of evolutionary relationships within a group

Iguana

Duck billed

constructed on the basis of shared characters

Hair, mammary glands

Duck‐billedplatypus

Kangaroo

Gestation

, y g Kangaroo

BeaverLong gestation

Phylogenetic Tree

Molecular SystematicsMolecular Systematics

– Compares nucleic acids or other molecules to inferCompares nucleic acids or other molecules to infer relatedness of groups of organisms

– The more recently two species have branched from a common ancestor, the more similar their DNA sequences should be

Constructing the tree of life is a work in progress

• The three domain

Constructing the tree of life is a work in progress

system was developed using the divergence of

Eukarya

the divergence of rRNA genes Bacteria Archaea

Most recent common ancestor of all living things1

Gene transfer between mitochondrial ancestorand ancestor of eukaryotes

Gene transfer between chloroplast ancestor

2

3and ancestor of green plants

Bacteria

23

1

Eukarya

Archaea

Billions of years ago

4 3 2 1 0

Major evolutionary stepsEukaryotic cells (aquatic)

l l k d l l kProtists‐ Diverse plant‐like and animal‐likeuni‐cellular & Multicellular

Multi‐cellularAnimals PlantsAnimals Plants‐ Invertebrates ‐MossesVertebrates Ferns‐ Vertebrates ‐ Ferns

‐ Cone‐bearing‐ FloweringFlowering

history of life on earth and classification.pptfaculty.sdmiramar.edu/bhaidar/bio 107...

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