Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

PowerPoint® Lecture Presentations for

Biology Eighth Edition

Neil Campbell and Jane Reece

AP Biology Curriculum 2012-2013

The origin of living systems is explained by natural processes. (1.D.2)

Big Idea 1: Evolution

26.6

Fig. 25-7

Animals

Colonizationof land

Paleozoic

Meso-

zoicHumans

Ceno-zoic

Origin of solarsystem andEarth

Prokaryotes

Proterozoic Archaean

Billions of years ago

1 4

32

Multicellulareukaryotes

Single-celledeukaryotes

Atmosphericoxygen

a. Geological evidence provides support for models of the origin of life on Earth.

1. The Earth formed approximately 4.6 bya, and the environment was too hostile for life until 3.9 bya, while the earliest fossil evidence for life dates to 3.5 bya. Taken together, this evidence provides a plausible range of dates when the origin of life could have occurred.

Scientific evidence from many different disciplines supports models of the origin of life. (1.D.2)

Scientific evidence from many different disciplines supports models of the origin of life. (1.D.2)

Fossilized prokaryote Living bacterium

Fig. 25-4i

Fig. 25-4jFossilized Precambrian stromatoliteearliest evidence of life, 3.5 bya

Stromatolite Shark Bay, Australia

•The earliest evidence of life, dating from 3.5 bya, comes from fossilized stromatolites.

•Stromatolites are layered rocks that form when certain prokaryotes bind thin films of sediment together.

•Present-day stromatolites are found in a few warm, shallow, salty bays.

Prokaryotes

Scientific evidence from many different disciplines supports models of the origin of life. (1.D.2)

Stromatolites in northern Canada

Banded iron formations: evidence of oxygenic photosynthesis (2.7 bya)

Fig. 25-8

•The early, gradual rise in atmospheric O2 due to ancient cyanobacteria.

Atmospheric Oxygen

•Free O2 dissolved in surrounding water, eventually reacting with dissolved iron producing the precipitate, iron oxide which accumulated as sediments.

•Banded iron formations are evidence of oxygenic photosynthesis. The reddish streaks are bands of iron oxide.

Fig. 25-9-4

Ancestral photosyntheticeukaryote

Photosyntheticprokaryote

Mitochondrion

Plastid

Nucleus

CytoplasmDNAPlasma membrane

Endoplasmic reticulum

Nuclear envelope

Ancestralprokaryote

Aerobicheterotrophicprokaryote

Mitochondrion

Ancestralheterotrophiceukaryote

Scientific evidence from many different disciplines supports models of the origin of life. (1.D.2)

•The oldest fossils of eukaryotic organism are about 2.1 billion years old.

•A model of the origin of eukaryotes through serial endosymbiosis The proposed ancestors of mitochondria were aerobic, heterotrophic prokaryotes (meaning they used oxygen to metabolize organic molecules obtained from other organisms). The proposed ancestors of plastids were photosynthetic prokaryotes. Note that the arrows represent change over evolution time.

Single-celled Eukaryotes

Fig 25-UN5

MulticellularEukaryotes

Billions of years

ago4

2

1

3

Multicellular Eukaryotes

Scientific evidence from many different disciplines supports models of the origin of life. (1.D.2)

•The oldest known fossils of multicellular eukaryotes are of relatively small algae that lived about 1.2 billion years ago.

Animals

Animals•The Cambrian Explosion. Fossils of at least three living animal phyla - Cnidarian, Porifera, and Mollusca appeared.

Colonization of Land

Colonization of Land•Large forms of life, such as fungi, plants, and animals begin colonizing land around 500 million years ago.

•The earliest tetrapods found in the fossil record bout 365 million years ago.

Fig. 22-16

2. Chemical experiments have shown that it is possible to form complex organic molecules from inorganic molecules in the absence of life.

Scientific evidence from many different disciplines supports models of the origin of life. (1.D.2)

Water vaporCH4

Electrode

NH3 H2

Condenser

Coldwater

Cooled watercontainingorganiccompounds

Sample forchemical analysis

H2O

The synthesis of organic molecules in the Miller-Urey apparatus

Harold Urey (1839-1981)

Stanley Miller ( 1930-2007)

Bozeman Biology: Abiogenesis (9:00 min.)http://www.youtube.com/watch?v=W3ceg--uQKM&feature=plcp

Fig. 25-21

Vertebrates (with jaws)with four Hox clusters

Hypothetical earlyvertebrates (jawless)with two Hox clusters

Hypothetical vertebrateancestor (invertebrate)with a single Hox cluster

Second Hox duplication

First Hox duplication

b. Molecular and genetic evidence from extant and extinct organisms indicates that all organisms on Earth share a common ancestral origin of life.

Scientific evidence from many different disciplines supports models of the origin of life. (1.D.2)

• Master regulatory genes called homeotic genes.

• Class of homeotic genes, the Hox genes, provide positional information in an animal embryo.

•Hox mutations and the origin of vertebrates. The vertebrate Hox complex contains duplicates of many of the same genes as the single invertebrate cluster, in virtually the same linear order on chromosomes, and they direct the sequential development of the same body regions.

1. Scientific evidence includes molecular building blocks that are common to all life forms.

2. Scientific evidence includes a common genetic code.

Scientific evidence from many different disciplines supports models of the origin of life. (1.D.2)

•Origin of the insect body plan Expression of the Hox gene Ubx suppresses the formation of legs in fruit flies (Drosphila) but not in brine shrimp (Artemia), thus helping to build the insect body plan. Fruit fly and brine shrimp Hox genes have evolved independently for 400 million years.

YouTube - Bozeman Biology: Origen of Life - Scientific Evidence (15:00 min.)http://www.youtube.com/watch?v=SWY3FKbtEz8&feature=plcp