figure 26.21 archaea bacteria eukarya common ancestor of all life land plants green algae red algae...

Figure 26.21

Archaea

Bacteria

Eukarya

COMMONANCESTOR

OF ALLLIFE

Land plants

Green algae

Red algae

ForamsCiliates

Dinoflagellates

Cellular slime moldsAmoebas

Animals

Fungi

EuglenaTrypanosomes

Leishmania

Sulfolobus

Thermophiles

Halophiles

Methanobacterium

Greennonsulfur bacteria

(Mitochondrion)

SpirochetesChlamydia

Cyanobacteria

Greensulfur bacteria

(Plastids, includingchloroplasts)

Diatoms

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)