Transcript Diagrams to Review C26

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1.7
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3.5
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P 494
Ancient Reducing Atmosphere
• Oparin and Haldane proposed that Earth’s
ancient atmosphere was reducing rather
than oxidizing.
• Why was there no free oxygen in Earth’s
early atmosphere?
• Why would the first life not evolve in an
oxidizing atmosphere?
Miller and Urey simulated
Earth’s early atmosphere
electricity simulated lightning
Why did they use uV light?
An alternate atmosphere
contained carbon monoxide,
carbon dioxide, nitrogen gas
and water vapor
Experiments have
produce all 20 amino
acids, sugars, lipids,
purines, pyrimidines
What is the importance of
amino acids?
What is the importance of
nucleic acids?
Formerly
eubacteria
Archaea live in
extreme
environments
and have cell
walls with no
peptidoglycan
Most bacteria
range from 15 um while
eukaryotes
range from 10100 um
Simple cell wall with
relatively large amounts
of peptidoglycan
Penicillin prevents
crosslinking in the
peptidoglycan and
prevents the formation
of a functional cell wall
More complex cell
wall with less
peptidoglycan but
with an outer
membrane with
lipopolysaccharides
-carbohydrates
bonded to lipids
Pseudomonas
Rhizobia
Nitrosomonas
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• Under one evolutionary scenario, the
endomembrane system of eukaryotes (nuclear
envelope, endoplasmic reticulum, Golgi
apparatus, and related structures) may have
evolved from infoldings of plasma membrane.
• Another process, called endosymbiosis,
probably led to mitochondria, plastids, and
perhaps other eukaryotic
features.
Fig. 28.4
Formation of Chloroplast
cyanobacteria green
algae green plants
Problems Aquatic Plants Face
in a Terrestrial Environment
• Obtaining enough water
• transporting water and
dissolved substances
from restricted areas of
intake to other areas
• Preventing desiccation
• Maintaining enough moist
surface area for gas
exchange
• carry out reproduction
in an environment
where sperm, zygote
and embryo will dry
out
• withstanding extreme
fluctuations in
environment
• Supporting a large
plant body against
gravity
Four Major Groups
Adaptations of Bryophytes
• form embryophytes
• Gametes develop
within gametangia
– anthridium
– archegonium
• Spores with walls of
sporopollenin
• cuticle
• stomata
• alternation of
generations
– the haploid
gametophyte is the
dominant generation
•
Bryophytes, pteridiophytes,
gymnosperms, ands angiosperms
demonstrate four great episodes in the
evolution of land plants:
1. the origin of bryophytes from algal ancestors
2. the origin of vascular plants and their
diversification
3. the origin of seeds
4. the evolution of flowers
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Fig. 29.1
Homologies between
Charophytes and Plants
• Homologous chloroplasts
– chlorophyll b, betacarotene
– thylakoids as grana
– DNA
• Biochemical similarity
– cellulose cell walls
(rosette cellulosesynthesizing complexes)
– matching enzymes
within peroxisomes
• Similar mitosis and
cytokinesis
– dissapearance of
nuclear envelope
– spindle remains till
cytokinesis
– Cell plate formation
• similar sperm
• similar genes and
rRNA
• The elongation and branching of the
shoots and roots maximize their exposure
to environmental resources.
• This growth is sustained by apical
meristems, localized regions of cell
division at the tips of shoots and roots.
– Cells produced by
meristems differentiate
into various tissues,
including surface
epidermis and
internal tissues.
Fig. 29.3
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•In pteridophytes, gymnosperms, and angiosperms,
the
The gametophyte is
bisexual producing
sporophyte
Most ferns areis the dominant generation.
homosporous
both sperm and eggs
•For example, the fern plant that we typically see is the
diploid sporophyte, while the gametophyte is a tiny plant on
the forest floor.
The cuticle is a secondary product
produced on the surface of leaves
to prevent dessication
Xylem
Phloem
The stomata is
an adaptation to
let in carbon
dioxide into the
leaf
Adaptations to Terrestrial Life
•
•
•
•
•
•
Stomata p582
Cuticle p581
lignin
Sporopollenin p580
gametangia p581
embryophytes
• vascular tissue p582
• seeds
• flowers
Adaptation of Vascular Plants
• Root systems
– absorbs water and
minerals
• Aerial shoot systems
and leaves
– for photosynthesis
• Conducting tissue
– xylem and phloem
• Lignin
– to strengthen and
support cellulose cell
walls
• Sporophyte is the
dominant stage
• Branching in
Sporangia
– increases the # of
spores
Most ferns are
homosporous
The gametophyte is
bisexual producing
both sperm and eggs
Microscopic
gametophytes of seed plants are even more reduced
than those of seedless vascular plants such as ferns
• An ovule consists of integuments,
megaspore, and megasporangium.
– A female gametophyte develops inside a
megaspore and produces one or more egg
cells.
– A fertilized egg develops into a sporophyte
embryo.
– The whole ovule develops into a seed.
Fig. 30.2
2. The four phyla of extant gymnosperms
are ginko, cycads, gnetophytes, and
conifers
• There are four
plant phyla
grouped as
gymnosperms.
Fig. 30.4
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Gymnosperm
only have
tracheids - no
vessels
Vessels form
contiunous tubes and
thus are more
specialized for
transport of water and
less for support.
The thick
lignified xylem
cell helps in
support
Monocot
Dicot
one embryonic leaf - cotyledon
two embryonic leaves - cotyledons
does not have vascular cambium and
secondary growth
has vascular cambium and secondary growth
scattered vascular bundles
leaves have parallel venation
no petioles
flower parts in multiples of three
vascular tissue arranged in circular bundles
leaves have netted venation
has petioles
flower parts in multiples of four or five
• Refinements in vascular tissue, especially
xylem, probably played a role in the
enormous success of angiosperms in
diverse terrestrial habitats.
– Like gymnosperms, angiosperms have long, tapered
tracheids that function for support and water transport.
– Angiosperms also have
fibers cells, specialized
for support, and vessel
elements (in most
angiosperms) that
develop into xylem
vessels for efficient
water transport.
Fig. 30.12
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• A flower is a specialized shoot with four
circles of modified leaves: sepals, petals,
stamens, and carpals.
Fig. 30.13a
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• The life cycle of an angiosperm begins with the
formation of a mature flower on a sporophyte
plant and culminates in a germinating seed.
Fig. 30.17
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3. Fruits help disperse the
seeds of angiosperms
• A fruit is a mature ovary.
– As seeds develop from ovules after fertilization,
the wall of the ovary thickens to form the fruit.
– Fruits protect dormant seeds and/or aid in their
dispersal.
Fig. 30.15
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1. Absorptive nutrition enables
fungi to live as decomposers and
symbionts
• Fungi are heterotrophs that acquire their
nutrients by absorption.
– They absorb small organic molecules from the
surrounding medium.
– Exoenzymes, powerful hydrolytic enzymes
secreted by the fungus, digest food outside its
body to simpler compounds that the fungus can
absorb and use. Extracellular digestion.
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2. Extensive surface area and
rapid growth adapt fungi for
absorptive nutrition
• The vegetative bodies of most fungi are
constructed of tiny filaments
called hyphae
that form an
interwoven
mat called a
mycelium.
Fig. 31.1
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Introduction
• More than 100,000 species of fungi are
known and mycologists estimate that there
are actually about 1.5 million species
worldwide.
• Molecular analyses
supports the division
of the fungi into four
phyla.
Fig. 31.4
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• The four fungal
phyla can be
distinguished by
their
reproductive
features.
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• The fungal hyphae provides most of the
lichen’s mass and gives it its overall shape
and structure.
• The algal component usually occupies an
inner layer below the lichen surface.
Fig. 31.17
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• Mycorrhizae are mutualistic associations of
plant roots and fungi.
– The anatomy of this symbiosis depends on the
type of fungus.
• The extensions of the fungal mycelium from
the mycorrhizae greatly increases the
absorptive surface of the plant roots.
• The fungus provides
minerals from the soil
for the plant, and the
plant provides organic
nutrients.
Fig. 31.18
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(3) The Bilateria can be divided by the
presence or absence of a body cavity (a
fluid-filled space separating the digestive
tract from the outer body wall) and by the
structure the body cavity.
• Acoelomates (the phylum
Platyhelminthes) have a solid body and
lack a body cavity.
Fig. 32.6a
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• In some organisms, there is a body cavity,
but it is not completely lined by mesoderm.
– This is termed a pseudocoelom.
– These pseudocoelomates include the rotifers
(phylum Rotifera) and the roundworms (phylum
Nematoda).
Fig. 32.6b
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• Coelomates are organisms with a true
coelom, a fluid-filled body cavity
completely lined by mesoderm.
– The inner and outer layers of tissue that
surround the cavity connect dorsally and
ventrally to form mesenteries, which suspend
the internal organs.
Fig. 32.6b
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• Many protostomes undergo spiral
cleavage, in which planes of cell division
are diagonal to the vertical axis of the
embryo.
– Some protostomes also show determinate
cleavage where the fate of each embryonic
cell is determined early in development.
• The zygotes of many deuterostomes
undergo radial cleavage in which the
cleavage planes are parallel or
perpendicular to the vertical egg axis.
– Most deuterostomes show indeterminate
cleavage whereby each cell in the early
embryo retains the capacity to develop into a
complete embryo.
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