Phylums of Protista

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Phylums of Protista
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Bacillariophyta

• Diatoms
• Double shell made of silica
• Photosynthetic
• Complicated life cycle
• Unicellular

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Chlorophyta

• Green algae
• Unicellular or multicellular
• Photosynthetic
• Probable ancestor of land plants
• Found in freshwater and marine
• Alternation of generations

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Rhodophyta

• Red algae
• Sea weeds
• Multicellular
• Photosynthetic
• Phycobilins
• Commercially valuable
• Alternation of generations

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Phaeophyta

• Brown algae
• Kelp, sargassum
• Marine
• Multicellular
• Photosynthetic
• Complex structures
• Alternation of generations

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Alternation of generations
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Rhizopoda

• Amoebas
• Move by use of pseudopodia
• Heterotrophic
• Unicellular
• Forams marine members of the group

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Dinoflagellata

• Dinoflagellates
• 2 flagella
• unicellular
• photosynthetic
• produce toxins

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Zoomastigina

• Unicellular
• Heterotrophic
• 1-1000s of flagella
• Some reproduce sexually
• Help termites
• Cause illness in humans

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Euglenophyta

• Euglena
• photosynthetic /or heterotrophic
• unicellular
• flagellum
• light sensitive

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Ciliophora

• Paramecium
• Unicellular
• Cilia to move
• Micronucleus macronucleus
• Conjugation

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Acrasiomycota

• Cellular slime molds
• Amoebalike
• Congregate and reproduce sexually during times of
  environmental stress

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Myxomycota

• Plasmoidial slime molds
• Mass of cytoplasm that moves like an amoeba
• Splits up and forms spores when conditions are bad

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Oomycota

• Water molds, white rusts, downy mildews
• Grow on dead organisms in water
• Parasites or decomposers

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Chytridiomycota

• Motile cells with a single flagellum
• Evidence for an evolutionary relationship with
  Kingdom Fungi

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Sporozoa

• Nonmotile
• Spore forming
• Unicellular
• Parasites
• Plasmodium causes Malaria

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MALARIA
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PROTIST CAUSED DISEASE
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KINGDOM FUNGI

• HETEROTROPHIC
• MULTICELLULAR, A FEW UNICELLULAR
• ABSORB NUTRIENTS FROM ENVIRONMENT
• DECOMPOSERS
• CHITIN CELL WALL
• NUCLEAR MITOSIS

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Fungi structure

• Filamentous body
• Filaments called HYPHAE
• Body called MYCELIUM
• Walls dividing cells are SEPTA

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Zygomycota

• Black bread mold
• Sexual structures are zygosporangia
• Asexual reproduction more common
• Dispersed by wind

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Ascomycota

• Sac fungi
• Spores form in a saclike ASCUS
• Usually reproduce asexually, but may reproduce
  sexually
• Distributed by wind

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Yeast

• Common and commercially important sac fungus
• Unicellular
• 350 species
• Some helpful, some harmful
• Budding or fission

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Basidiomycota

• Club fungi
• Usually reproduce sexually
• Smuts and rusts reproduce asexually and are plant
  pathogens
• Mushrooms and puffballs are common examples

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Mushroom
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KINGDOM PLANTAE

• Multicellular
• Photosynthetic
• Cellulose cell walls
• Alternation of generations
• Asexual reproduction
• Contain chlorophyll
• Autotrophic

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Adaptations to land

• 440 mya, plants fungi invaded land
• Mycorrhizae probably helped with mineral
  absorption
• Fungi absorb minerals
• Found in 80 of todays plants

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Conserving water

• Cuticle - waxy covering
• Stomata - pores in leaves, permit gas exchange
  and limit water loss
• Guard cells control size of opening in stomata

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Reproduction on land

• Early/primitive plants required a film of water
  for sperm to swim to egg
• Egg protected by layer of cells
• More advanced plants use pollen to transfer sperm
  without a film of water present
• Seeds and spores tolerate dry conditions

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Vascular system

• In dry conditions, permits movement of water and
  nutrients within the plant
• Pipeline of specialized hollow cells within the
  plant
• Runs from top to bottom and to each leaf
• 3 divisions lack a vascular system

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Alternation of generations

• Method used by plants to reproduce sexually
• Sporophyte generation (2n) uses meiosis to
  produce spores (n)
• Gametophyte generation (n) uses mitosis to
  produce gametes (n)
• Gametes fuse to produce zygote (2n)

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Divisions of Plantae
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Hepatophyta

• Liverworts
• Nonvascular
• Simplest plants
• Gametophyte dominant

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Anthocerophyta

• Hornworts
• Nonvascular
• Gametophyte dominant
• Has stomata

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Bryophyta

• Mosses
• Simple vascular tissue
• Gametophyte dominant
• Lacks true roots, leaves, and stem
• Sporophyte grows on female gametophyte
• Requires moist habitat

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Moss life cycle/ alternation of generations
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Vascular plants

• Have true vascular tissue
• Less dependent on water or high humidity than
  nonvascular plants
• All of the following divisions are vascular
  plants.

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Psilophyta

• Whisk ferns
• Seedless
• Dominant sporophyte
• Independent gametophyte
• Has leaves but no true roots or stem
• True vascular plant
• Found in tropics

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Sphenophyta

• Horsetails
• Seedless
• Dominant sporophyte
• Independent, small gametophyte
• Ribbed, jointed stems w/ soft needle-like leaves
  at joints
• Found near rivers or streams

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Lycophyta

• Club mosses
• Seedless
• Dominant sporophyte that looks like moss
• Independent gametophyte
• Fossilized tree forms were once up to 50 feet
  tall, today rarely more than 1 foot tall

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Pterophyta

• Seedless
• Dominant sporophyte
• Roots, horizontal stems, fronds
• Spores produced in clusters of sporangia

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Fern life cycle
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Coniferophyta

• Gymnosperms
• Ovules not in ovary
• Produce cones
• Leaves as needles or scales
• Tiny gametophyte
• Large, dominant sporophyte

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Conifer life cycle
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Adaptations of conifers

• Leaves reduced to needles or scales
• Very waxy cuticle
• Wind pollenation
• Soft wood
• Cones

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Cycadophyta

• Gymnosperms
• Palmlike leaves
• Male female cones on separate plants
• Cardboard palm

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Ginkgophyta

• Gymnosperm
• Deciduous
• Conelike male structures and uncovered seeds on
  separate individuals
• Only 1 living species

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Gnetophyta

• Gymnosperms
• Diverse group of shrubs and vines

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Anthophyta

• Flowering plants
• Angiosperms - ovules in an ovary
• Tiny gametophytes
• Dominant sporophyte
• Diverse group
• Divided into monocots and dicots

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Plant structure

• Leaves
• Stem
• Roots
• Flowers

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Plants are made of 3 types of tissue

• DERMAL TISSUE - protective outer layer
• GROUND TISSUE SYSTEM - photosynthesis, storage,
  transport, surrounds/supports conducting tissues
• VASCULAR TISSUE - moves water, mineral nutrients,
  carbohydrates

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General structures
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Leaves

• Site of most photosynthesis
• Attached to stem by petiole
• Vascular tissue forms veins
• May be modified for other jobs or situations

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Leaf cross section
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Leaf components

• GROUND TISSUE -- mesophyll, site of
  photosynthesis
• DERMAL -- epidermis, produces cuticle
• VASCULAR -- veins (xylem phloem), transports
  water, nutrients, carbohydrates
• Air spaces stomata -- gas exchange

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Stem components

• Nodes - where leaves attach
• Internodes - areas of stem between nodes
• Lateral buds - become branches
• Terminal bud - tip of stem
• Cortex - ground tissue layers
• Pith - inner layers

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Herbaceous stems

• Soft, flexible
• Usually green
• Outermost layer epidermis
• Vascular bundles
• Can carryout gas exchange w/ stomata

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Woody stems

• Stiff, rigid
• Not green
• Heartwood dead xylem
• Sapwood live xylem
• Phloem forms outer cylinder
• Cork cells replace epidermis

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Comparison of stems
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Stem modifications
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Root structures

• Vascular tissue at center
• Cortex surrounds vascular tissue
• Dermis on outside
• Root hairs - extensions of dermal cells, increase
  surface area
• Root cap - protective layer of cells at tip

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Structure of roots
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Root modifications
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Movement of water

• Water enters through roots
• Moves through stem in the xylem
• Is lost by transpiration through the stomata
• Tension-cohesion theory -- water molecules pull
  each other along up the xylem (cohesion
  adhesion w/ hydrogen bonds)

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Water movement
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Guard cells regulate the rate of transpiration by
opening/closing stomata
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Sugars are moved through a plant by the process
illustrated by the pressure-flow model.
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Sugar transport

• Source - part of plant providing sugar
• Sink - part of plant where sugar is stored (this
  what we usually eat)
• Translocation - movement of sugar
• Combination of osmosis diffusion and the
  pressure they create move the sugar

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Flowering plant reproduction

• Flowers are complex reproductive structures
• Produce seeds (aid in distribution)
• Some produce fruit

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Seed structure
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Functions of seed structures

• Endosperm - energy source for embryo
• Cotyledons - embryonic leaves
• Embryo - potential plant
• Seed coat - protection of embryo and its food
  source

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Seed modifications for dispersal
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Origin of seed fruit structures from flowers
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Plant development
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Flower structure
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Functions of flower parts

• Carpel/pistil - female part of flower contains
  ovary w/ ovule, makes eggs
• Stamen - male part of flower filament supports
  anther that makes pollen
• Petals - entice pollenators
• Sepals - may help entice pollenators or protect
  flower bud

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Angiosperm lifecycle
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Monocots v. Dicots
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Examples of monocots
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Dicots
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Primary Growth

• Growth at tips of roots and stems
• Occurs in apical meristem
• Apical meristem uses hormones to control growth
• Produces primary tissues
• As they grow, the cells differentiate into tissues

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Apical meristem
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Secondary growth

• Lateral meristems produce secondary growth
• Produces secondary tissues
• Thickens the stems and roots
• Adds layers of cells around the plant

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Plants continue to grow

• Plants grow throughout their lives
• Differentiation continues through the entire
  life, but is reversible
• Can clone a plant by culturing ANY of its cells
• Tissue culture is important in commercial plant
  production (orchids)

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Plant life cycles

• ANNUALS - complete life cycle in 1 year
• BIENNIALS - complete life cycle in 2 years
• PERENNIALS - complete life cycle in more than 2
  years DECIDUOUS - shed leaves periodically
  EVERGREEN -shed a few leaves at a time, all the
  time

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Role of nutrients

• Required for growth
• Use CO2 H2O
• Mineral nutrients are derived from soil
• nitrogen -- proteins, nucleic acids,
  chlorophylls, coenzymes
• phosphorous -- ATP/ADP, nucleic acids,
  phospholipids, coenzymes
• potassium-- active transport, activate enzymes,
  osmotic balance, open stomata
• magnesium -- chlorophyll, photosynthesis,
  activate enzymes
• sulfur -- proteins, coenzyme A, cellular
  respiration

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Plant hormones

• 1851, Charles Francis Darwin
• Experimented on growth of young plants toward
  light (phototropism)
• Gelatin caps allowed light to reach the tip of
  the plant, plant would bend
• If light were blocked from the tip, the plant
  would not bend
• Concluded that there was a signal generated by
  the tip
• Today, we call it a hormone.

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Darwins experiment
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Types of plant hormone

• AUXIN
• produced in tips of stems
• maintains apical dominance and controls leaf
  fruit drop
• CYTOKININS
• produced in root tips
• stimulate cell division, promote lateral growth,
  inhibit leaf drop
• ETHYLENE
• produced in most tissues
• stimulates ripening, promotes bud/leaf/fruit
  drop, slows lateral growth
• GIBBERELLINS
• produced in developing shoots and seeds
• stimulate cell division and elongation, seed
  germination fruit development

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Tropisms

• Growth response by a plant
• PHOTOTROPISM - stem grows toward light ()
  roots grow away from light (-)
• GRAVITROPISM - upward growth of stem (-) growth
  of roots toward gravity ()
• THIGMOTROPISMS - growth responses to touch
  (tendrils wrapping around a twig)

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Thigmotropism, Phototropism, Gravitropism
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Photoperiodism

• Response of plant to length of day
• Short-day plant - responds when day shorter than
  critical length
• Long-day plant - responds when day longer than
  critical length
• Day-neutral plant - not affected by day length

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Day length plants
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Dormancy

• Condition in which plant or seed remains inactive
  for long period of time
• Probably initiated by ABSCISIC ACID (a plant
  hormone)
• Usually broken when conditions are favorable for
  growth
• Different plants use different strategies

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Kingdom Animalia

• Phyla, Characteristics, and Evolutionary Trends

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Animals

• Heterotrophs
• Ingest food
• Multicellular
• No cell wall
• Most able to move
• Most reproduce sexually
• Symmetry
• Tissues and organs

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Evolutionary Stages in Animals

• Multicellularity - organisms made of more than 1
  cell
• Tissues - cells working together to perform a
  task
• Bilateral symmetry - equal right and left halves
• Body cavity - space for organs
• Coelom - body cavity lined with endoderm
• Segmentation - specialization repetition
• Jointed appendages - greater flexibility
• Deuterostomes - more cell specialization, 2
  openings
• Notochord - support for dorsal nerve cord

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Animal phyla
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Invertebrates

• Animals without backbones
• About 99 of all animals
• Wide diversity
• Highly successful group

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Porifera

• Multicellular
• No specialized tissues
• Asymmetrical
• Filter feeders
• Sessile
• Spicules protein fiber support
• Amoebocytes - mobile cells in the sponge
• Regenerate
• Choanocyte resembles choanoflagellates,
  evolutionary link

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Sponge diversity
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Sponge reproduction
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Phylum Cnidaria

• Radial symmetry
• Eumetazoans (3 distinct tissue layers)
• All aquatic
• 3 classes
• 2 basic body plans - polyp medusa
• Extracellular digestion
• Cnidocytes Nematocysts
• Reproduce sexually asexually (budding)

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Eumetazoan tissue layers

• Endoderm
• innermost layer
• digestive tube associated organs
• Mesoderm
• middle layer
• skeleton muscles
• Ectoderm
• outermost layer
• external coverings nervous system

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Class Hydrozoa

• Freshwater hydras - individuals, polyp
• Portuguese man-of-war
• colonies
• medusa polyp
• Basal disk - makes sticky substance used to hang
  on
• tentacles used to catch prey
• planula larvae

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Hydra movement
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Hydrozoa reproduction
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Class Scyphozoa

• Jelly fish
• Medusa form dominant
• Float in water, weak swimmers
• Active predators
• Cnidocytes/nematocytes - special cells that
  inject venom into the prey
• Microscopic to 100 yards long

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Class Anthozoa

• Corals, sea anemones
• Polyp form dominant
• Predators
• Use tentacles to trap prey
• Corals have symbiotic dinoflagellates called
  zooxanthellae

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Phylum Ctenophora

• Comb jellies
• Minor phylum related to Cnidaria
• Carnivores that capture their prey with their
  tentacles

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Phylum Platyhelminthes

• Flatworms
• Bilateral symmetry
• Cephalization
• Organs present
• No respiratory or circulatory systems
• Only 1 body opening
• Acoelomate
• Some free-living species, most parasitic
• 1mm - 10 m

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Bilateral symmetry
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Class Turbellaria

• Planarians
• Free living
• Pharynx - muscular built in straw used to feed
• Marine freshwater species

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Class Trematoda

• Parasitic flatworms
• endoparasites - inside host
• ectoparasites - outside host
• Flukes
• Complicated life cycles with 2 or more hosts
• Cause Schistosomiasis, Human liver fluke

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Fluke lifecycle
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Class Cestoda

• Tapeworms
• Endoparasites
• Lack mouths digestive systems
• Proglottids - segments that are reproductive
  factories
• Up to 12 m / 40 ft long
• Beef tapeworm infects humans

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Beef tapeworm
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Phylum Rhynchocoela

• Ribbon worms
• Marine
• 0.31 m -30 m long (up to 100 ft)
• Acoelomate
• Digestive tube with 2 openings
• Circulatory system
• Predators

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Phylum Nematoda

• Round worms
• Pseudocoelomate - cavity between endoderm and
  mesoderm
• Muscles lengthwise - causes wriggling motion
• Gut with mouth anus
• Free living parasitic
• Most are microscopic
• Commonly found in soil
• Ascaris, Necator, Trichinella human parasites

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Advantages of pseudocoelom

• Allows fluids to circulate in the cavity
• Fluids in cavity make body rigid (hydrostatic
  skeleton) allowing muscles to produce movement
• Organ function is improved because less
  distortion occurs
• 7 phyla considered pseudocoelomates

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Phylum Rotifera

• Rotifers
• Free-living, microscopic predators
• Require moist habitat
• Row of cilia surrounds mouth, pulls prey into
  mouth
• 2 body openings and pseudocoelom

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Rotifer
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Phylum Tardigrada

• Water bears, moss piglets
• Pseudocoelomates
• Predators or herbivores
• Cryptobiosis
• Complex animals
• Found in all ecosystems

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Water bear
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Phylum Mollusca

• Coelomate-
• fluid filled body cavity entirely within the
  mesoderm
• primary induction (interaction of the 3 tissue
  types) causes differentiation of tissues during
  development
• Bilateral symmetry

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• Organ systems
• circulation
• open, blood leaves vessels, bathes muscles
• heart has 2 chambers that receive blood from
  gills, 1 chamber pumps blood to body
• closed system - blood never leaves vessels
• respiration
• gills in mantle cavity, through skin, or
  primitive lung
• digestion
• excretion
• nephridia remove wastes from bodily fluids
• 3 part body plan - muscular foot, head, visceral
  mass

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Mollusc diversity

• 7 classes
• probable ancestor - flattened, unsegmented,
  wormlike animal
• Polyplacophora - most primitive class, commonly
  called chitons

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Class Bivalvia

• Clams, oysters, scallops
• 2 shells (valves) with a hinge
• shells secreted by the mantle (tissue that covers
  the visceral mass)
• adductor muscles close the shell by contracting
• use the foot to dig
• sessile filter feeders
• no distinct head or brain (nerve ganglia remain
  above the foot)

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• siphons - tubes through which water passes
• gills - gas exchange
• mucus covers gills traps food, mucus is moved to
  the mouth by cilia, food removed
• reproduce sexually
• separate sexes
• external fertilization
• development -- embryo --gt trochophore larvae --gt
  veliger larvae --gt adult
• commercially valuable for food and pearls

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Clam anatomy
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Class Gastropoda

• snails, slugs, nudabranchs
• stomach footed animals
• mostly marine, some freshwater terrestrial
• use the foot for motion
• terrestrial species secrete mucus from the foot
  to aid movement

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• eyes located on tentacles on the head
• slugs nudibranchs lost the shell
• snails - univalves (1 shell)
• torsion - visceral mass rotates 180o during
  development, mantle cavity moves to the front of
  the animal
• gas exchange - gills, skin, or primitive lung
• herbivores use radula to graze on algae
• carnivores use radula to spear or drill prey
• some species inject venom with radula (cone
  shells)

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nudibranch slugs
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Cone shell hunting
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Class Cephalopoda

• squids, octopuses, chambered nautiluses,
  cuttlefishes
• head footed animals
• foot divided into tentacles
• head attached directly to foot
• tentacles have suction cups /or hooks used to
  capture prey

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View of octopus tentacles
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• Use jet propulsion to move (force water out of
  siphon from the mantle)
• highly intelligent (complex nervous system) even
  show problem solving skills
• well developed, complex eyes
• separate sexes
• internal fertilization
• lays eggs

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Phylum Annelida

• true coelom
• segmentation
• nearly identical
• some fuse during development
• some stay separate
• organ systems
• highly specialized gut
• closed circulatory system
• many nephridia

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• bristles
• setae - external hairs
• parapodia - fleshy appendages
• lots of specialization
• cephalization
• closed circulatory system
• faster, more pressure
• larger vessels act as hearts
• gas exchange through body surfaces
• excretion by nephridia
• ciliated funnel shaped structures
• 1 pair / segment
• wastes exit through pores

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Annelid characteristics
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Polychaetes

• Marine segmented worms
• Powerful, free-living predators burrowers
  filter feeders
• Well developed head
• Parapodia (fleshy projects on each segment)
• Separate sexes
• External fertilization
• Trochophore larvae

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Oligochaetes

• Earthworms
• terrestrial
• eat their way through the soil
• gizzard grinds organic material
• head eyes greatly reduced

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Hirudinea

• Leeches
• suckers at both ends
• crawl
• aquatic habitats
• 1 to 1 long
• predators, scavengers, parasites

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Phylum Arthropoda

• probably evolved from annelids
• velvet worms (Onycophorans) show blend of annelid
  arthropod characteristics
• DNA shows actually arthropods closely related to
  scorpions, not separate phylum

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• trilobites were the most successful marine group
  of arthropods
• became extinct 250 million years ago
• 3 lobes on body
• very diverse widely distributed group
• scorpions were first terrestrial arthropods
• 425 million years ago
• evolved from sea scorpions (now extinct)

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Mandibulates v. Chelicerates

• Mandibulates - 1st pair of appendages modified
  into jaws
• crustaceans, insects, centipedes, millipedes
• Chelicerates - 1st pair of appendages modified
  into fangs or pincers
• mites, spiders, scorpions

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Body plan characteristics

• jointed appendages - allow flexibility
• segmentation - may fuse segments
• head - most have separate head, some have fused
  head thorax (cephalothorax)
• exoskeleton - chitin, some also have calcium
  carbonate
• compound eyes - not clear images, but excellent
  motion detectors
• ommatidia - individual units of compound eyes
• ocelli - single lens, no images, detect light
  dark
• circulation - open system, heart on top, blood
  flows through body spaces

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• spiracles - terrestrial respiration
• tracheae - tubes
• spiracles - openings, controled by valves, limit
  water loss

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Malpighian tubules - excretory system -
eliminates wastes, saves water - extend from
gut, filter contents of blood
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• wings - insects were first animals to fly
• ecdysis - molting
• to grow, must shed old exoskeleton
• triggered by hormones

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Arthropod diversity
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Arachnids

• Spiders, mites, ticks, granddaddy longlegs,
  horseshoe crabs, sea spiders
• Chelicerae (fangs/pincers)
• palps (catch / handle prey)
• all except mites are carnivores
• primarily terrestrial

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Scorpions

• palps are pincers
• venomous stinger
• evolved from eurypterids (sea scorpions)
• first terrestrial arthropods

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Spiders

• chelicerae modified into venomous fangs
• webs used for capturing prey and protection
• predators

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Mites

• largest most diverse group of arachnids
• includes chiggers ticks
• all segments are fused
• 8 legged adult
• marine aquatic species are herbivores
• terrestrial species are carnivores

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Crustaceans

• primarily aquatic
• crabs, lobsters, crayfish, shrimps, barnacles,
  water fleas, pill bugs
• mandibulates

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Crustacean characteristics

• appendages branched at ends
• naupilus larva
• exoskeleton contains calcium carbonate
• 2 pairs of antennae
• 3 pairs of chewing appendages
• legs attached to abdomen and thorax
• breathe with gills

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Decapods

• 5 pairs of walking legs
• cephalothorax - head thorax fused
• carapace - top shield on cephalothorax
• swimmerets - appendages on abdomen used to swim
  in reproduction
• uropods - flattened, paddle-like appendages at
  the end of the abdomen
• telson - tail spine
• largest arthropods (lobster, crabs, crayfish)
• most are minute (copepods, daphnia)
• terrestrial species pill bugs (isopods)

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Uniramia

• most millipedes, centipedes, insects
• are terrestrial able to fly
• millipedes centipedes -
• head segments
• millipedes - 2 pairs of legs / segment
• centipedes - 1 pair of legs / segment

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• insects
• largest group of animals on earth
• primarily terrestrial
• 7 common orders
• most are small
• segmentation
• head, thorax, abdomen
• 3 pair of legs attached to thorax
• 1 pair of antennae
• no wings or 1 or 2 pairs of wings attached to the
  rear segments of the thorax (2nd or 3rd segment)
• wings are solid chitin
• metamorphosis - change from juvenile to adult
• social insects - Hymenoptera (bees, ants, wasps)
  isoptera (termites)
• caste determined by genetics or food

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Incomplete metamorphosis (10 of insects) v.
Complete metamorphosis (90 of insects)
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Echinoderms

• sea urchins, sea stars, sea cucumbers, sea lilies
• adults
• radial symmetry 5 part body plan
• no head or brain
• nervous system ring of nerves with branches
• larvae have bilateral symmetry
• endoskeleton - ossicles (calcium plates), spines
  may project out
• 5 part radial symmetry
• water vascular system - tube feet, used for
  movement

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• coelomate
• body cavity acts as simple circulatory system
• respiration waste removal by skin gills
• 20 extinct classes, 5 living classes
• Asteroidea -
• sea stars
• carnivores
• 5 arms with central disk
• Feather stars sea lilies-
• mouth on upper surface
• sea lilies most primitive echinoderm, sessile
• Brittle stars
• slender branched arms

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• Sea urchins sand dollars
• no arms
• hard exoskeleton
• grazers
• Sea cucumbers
• skeleton not fused, body soft
• mouth surrounded by tube feet modified into
  tentacles used for feeding
• when threatened regergitates its internal organs
  and crawls away
• Echinoderm diversity illustrated on next slide

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Invertebrate chordates

• Phylum Chordata
• 3 subphyla
• Urochodata
• tunicates
• sessile, filter feeding adults
• larvae have coelom, dorsal nerve cord, notochord,
  bilateral symmetry (chordate characteristics)

172

• Cephalochordata
• lancelets
• scaleless, fishlike animals
• small
• no head or eyes
• probably direct ancestors of fish

173
Chordate relationships