Transcript Diversity of Life

Figure 26.21
Eukarya
Land plants
Green algae
Dinoflagellates
Forams
Ciliates
Diatoms
Red algae
Cellular slime molds
Amoebas
Euglena
Trypanosomes
Leishmania
Animals
Fungi
Green
nonsulfur bacteria
Sulfolobus
Thermophiles
(Mitochondrion)
Spirochetes
Halophiles
COMMON
ANCESTOR
OF ALL
LIFE
Chlamydia
Green
sulfur bacteria
Bacteria
Methanobacterium
Archaea
Cyanobacteria
(Plastids, including
chloroplasts)
Prokaryotes vs. Eukaryotes
• Unicellular, some colonial
• Typically 0.5um diameter
• Various shapes
• Well organized, all life functions are within one
cell
Bacterial Shapes
Domain Archea
• Share some traits with Bacteria and some with
eukaryotes
Bacteria
Archaea
Eukarya
RNA Polymerase
One
Several
Several
Introns
Rare
Present
Present
Response to
antibiotics
Growth
inhibited
Not inhibited Not inhibited
Histones asso.
With DNA
Absent
Present in
some
Present
The Archaea
• Live in extreme environments
• Extremophiles
• Extreme halophile
• Extreme thermophile
• Methanogens
Domain Bacteria
• Include the majority of familiar bacteria
• Some are pathogenic
• Some are beneficial
Cell Structure
• Cell wall, Bacteria have peptidoglycan
• Gram staining can divide into 2 groups
• Gram positive – simple walls, less peptidoglycan
• Gram negative – less peptidoglycan, structurally more
complex, outer layer of lipopolysaccharide
• Capsule or slime layer
• Protect against dehydration, stick to surface, shield
against attacks by immune systems
• Motility by flagella
• Fimbrae used to attach cell to surface
• One large, circular DNA
A few examples of Bacterial Types
Roles in the Biosphere
• Chemical Recycling
• Carbon cycle
• Nitrogen cycle
• Ecological Interactions
• Symbiotic relationships
• Pathogens
Domain Eukarya
• Protista
• Fungi
• Planta
• Animalia
Protista
• Remember that the field of taxonomy is
constantly evolving
• Eukarya is divided into 5 supergroups that
include planta, animalia, fungi and protista
• Most protista are unicellular
• All are eukaryotic
Excavata
• Based on morphological studies of the cytoskeleton
• Some have “excavated” feeding groove
• Each group is monophyletic
• Diplomonads/Parabasalids – lack plastids, have modified
mitochondria, often anaerobic
• Giardia, Trichomonas
• Euglenozoans – rod or crystalline structure inside the flagella
• Kinetoplastids - Trypanosoma
• Euglenid - Euglena
Chromalveolates
• Evolved from Secondary Endosymbiosis –
common ancestor engulfed a single celled red
algae
• Monophyletic groups
• Alveolates, Stramenopile
Alveolates
• Membrane bound sacs
under the plasma
membrane
• Dinoflagellates – cellulose
plates, groves for flagella
• Apicomplexans – complex
life cycle, animal parasites
• Ciliates – use cilia for
movement, feeding; two
types of nuclei and
conjugation
Conjugation in ciliates
Stramenopile
• Important photosynthetic organisms
• Characteristic flagellum with numerous, hairlike
projections
• Diatoms, Golden and Brown algae, Oomycetes
•
Diatom
• Unicellular algae
• Wall made of silica
• Diatomaceous earth
• 100,000 living
species
Golden Algae
• Yellow and brown
carotenoids
• Biflagellated
• Mostly unicellular,
some colonial
Brown Algae
• Multicellular marine
‘seaweed’
• Carotenoid pigments
• Thallus - plantlike algal
body
• No stem, root or leaves
• Leaflike blades with
airfilled floats, and
holdfast
• Food, thickening agent
Alteration of Generations
Oomycetes
• Water mold, white rust,
downy mildew
• Previously fungi
• Cell walls are cellulose
• Convergent evolution
• No plastids, no
photosynthesis
• Phytophthora – caused
potato blight in 19th
century, known as the
Irish famine
Rhizarians
• Defined by similarity in
their DNA
• Vary in morphology
• Monophyletic group
• Radiolarians
• Forams or foraminifera
• Cercozoans
• Often referred to as
amoebas because
have threadlike
pseudopodia
Red and Green Algae
• 475 mya, a heterotrophic protist acquired a
cyanobacterial endosymbiont = red and green
algae
• Archaeplastida – red, green algae and land plants
evolved from a common ancestor
Red Algae
• Red color due to
phycoerythrin, masks
chlorophyll
• Pigments absorb red/green
light which absorb deeper
• Multicellular, diverse
lifecycles
• Porphyra or Nori
Green Algae
• Cellular structure
similar to that of land
plants
Unikonts
• Related to fungi and animals, very diverse
• Some research says these were the first
eukaryotes to diverge from other eukaryotes.
• Amoebozoans – lobe shaped pseudopodia
• Entamoeba – parasitic
• Gymnamoeba - soil, freshwater, marine
• Slime molds – cellular and plasmodial
Plasmodial Slime Mold Life Cycle
Plants
• Land plants evolved from green algae ancestor
• Adaptations for movement to land
• Ability to survive out of water
• Brighter light
• More carbon dioxide that water
• Soil rich in nutrients
• Few herbivores and pathogens in the beginning
• Challenges to living out of water
• Scarcity of water
• Lack of structural support
Four traits that appear in land plants,
but not in ancestral algae
1. Alternation of generations and
multicellular, dependent embryos
2. Walled spores produced in sporangia
3. Multicellular Gametangia
4. Apical Meristems
Table 29.1
Moss
• Moss consists of
gametophytes
• Blades are often
one cell thick
• Often have a
thick cuticle
Liverworts
• Liver-shaped gametophytes are elevated on
thallus
• Marchantia
Hornwort
• Long tapered
sporophyte
• Lacks seta, only
sporangium is
present
Seedless Vascular Plants
• Sperm are flagellated and must swim through a
film of water to fertilize the egg
• Lycophyta – club mosses, spike moss and
quillworts
• Pterphyta – ferns, horsetails, Psilophyta (whisk
ferns)
Lycophyta
• Often are epiphytes – use other plants as
substrate but are not parasites
• Upright stems with small leaves
Pterophyta
• Ferns, Horsetails, Whisk ferns
Importance of Seedless Plants
• Devonian and
Carboniferous
periods, forming
the first forests
• Rapidly removed
carbon dioxide
from atmosphere,
resulting in glacial
periods
• Eventually became
coal
Adaptations of Seed Plants
Seed Plants
• Gymnosperms – naked seeds on cones
•
•
•
•
Ginkgophyta
Cycadophyta
Gnetophyta
Coniferophyta
• Angiosperms
• Anthophyta – flowering plants
Ginkgophyta
• Only
surviving
species of
this phylum
• Ginko biloba
Cycadophyta
• Large cones and
palmlike leaves
• Thrived in
Mesozoic era
Gnetophyta
Coniferophyta
• 600 species
Angiosperm
Monocot
• One cotyledon
• Parallel veins
• Vascular tissue
scattered
• Roots fibrous
• Pollen grain has 1
opening
• Floral parts in 3s
Dicot
•
•
•
•
•
Two cotyledons
Veins netlike
Vascular tissue in a ring
Taproot present
Pollen grain has 3
openings
• Floral parts in 4 or 5
Fungi
• Heterotrophic,
feed by absorption
• Multicellular,
some unicellular
• Cell wall is chitin
• Filaments called
hyphae =
vegetative
• Mycelium =
reproductive
Chytrid
• Globular fruiting body forms multicellular
branched hyphae
• Flagellated spores
• Earliest fungal group to diverge?
Zygomycetes
• Decomposers, parasites, commensal symbionts
• Cause a great deal of food spoilage
• Black bread mold
Glomeromycetes
• Many plants form mycorrhizal associations with
these fungi
Ascomycetes
• Sac fungi
• Cup-shaped fruiting body
Basidiomycetes
• Mushrooms,
puffballs, shelf fungi
• Concentrates growth
in hyphae of
mushrooms and
produces fruiting
structures rapidly
Importance of Fungi
• Decomposers
• Mutualism relationships with plants and animals
• Lichens
• Pathogens
Animal Diversity
• Multicellular
• Heterotrophic
• Animals cannot make all their own organic molecules
so the have to ingest them
• Tissues develop from embryonic layers, muscle
and nervous tissues are unique
• No cell walls, instead have internal support, ie.
collagen
Early Embryonic Development
Invertebrates
Porifera
• Sessile animals
• Lack true tissues
• Suspension feeders
Cnidaria
• Corals, jellies, hydras
• Radially symmetrical
• Single opening serves
as mouth and anus
Lophotrochozoa
• Wide range of body
types
• Bilateral
• Digestive tract with
two openings
• Flatworms, Rotifers,
Annelida, Mollusca
Edysozoa
• Shed a tough external
coat as they grow, called
molting
• Nematoda, Arthropoda
(insects), Chelicerates
(arachnids), Crustaceans
Deuterostomia
• Radial cleavage,
formation of anus
from blastopore
• Chordata,
Echinodermata
Figure 33.UN06
Vertebrates
• Characteristics of Vertebrates
• Notochord – a skeletal structure in all chordate
embryos and some adults
• Dorsal, hollow nerve cord
• Pharyngeal slits or clefts – modified for gas exchange
and are known as gill slits
• Muscular, post-anal tail – tail extends past the anus
Chordate Characteristics
Lancets
Tunicates
• Characteristics are seen in larval stage
• Adult stage become sessile and vertebral
characteristics are lost
Craniates
• Chordates with a head
• Hagfish
• Skull of cartilage, no jaws or vertebrae
Vertebrates
• Craniates with a backbone
Lampreys
• Craniates with a backbone
• Jawless
Chondrichthyans
• Vertebrates with jaws
• “cartilage fish”
• Sharks, rays, skates
Ray-finned Fish - Osteichthyans
• Aactinopterygii
• Actinistia
• Dipnoi
• Operculum – bony flap
over the gills
• Swim bladder
• Lobe vs ray finned
Tetrapods
• Amphibians
• Amniotes
• Reptiles
• Turtles, alligators, crocodiles, birds
• Mammals
• Monotremes (egg layers)
• Marsupial
• Eutherians (placental)