Tree of Life The tree of life according

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Tree of Life The tree of life according to Ernst Haeckel, 1891

Tree of Life The tree of life according to Ernst Haeckel, 1891

How does Porifera fit in? Porifera 3 body types choanocytes cellular level of organization

How does Porifera fit in? Porifera 3 body types choanocytes cellular level of organization unknown common ancestor Blastula stage heterotrophic multicellular eukaryote Other animals

How does Cnidaria fit in? Cnidaria Porifera Other animals 3 body types choanocytes cellular

How does Cnidaria fit in? Cnidaria Porifera Other animals 3 body types choanocytes cellular level of organization Blastula stage heterotrophic multicellular eukaryote unknown common ancestor

Phylum Cnidaria

Phylum Cnidaria

Level of Organization Tissue • cells are organized into tissues and work together to

Level of Organization Tissue • cells are organized into tissues and work together to accomplish physiological functions

Tissue Layers Diploblastic = 2 germ layers • endoderm gastrodermis • ectoderm epidermis mesoglea

Tissue Layers Diploblastic = 2 germ layers • endoderm gastrodermis • ectoderm epidermis mesoglea • gelatinous matrix between the 2 layers epidermis gastrovascular cavity mesoglea gastrodermis

General Body Plan • sac-like body (only 1 opening) • Food and waste go

General Body Plan • sac-like body (only 1 opening) • Food and waste go in/out the same opening no anus! • water within GVC acts as a hydrostatic skeleton oral surface gastrodermis mesoglea epidermis aboral surface mouth Gastrovascular cavity

General Body Forms 2 different body forms are usually present in the life cycle:

General Body Forms 2 different body forms are usually present in the life cycle: polyp & medusa ** one animal may pass through both forms during its life **

General Life Cycle

General Life Cycle

Radial Symmetry - body parts are arranged concentrically around an oral-aboral axis oral aboral

Radial Symmetry - body parts are arranged concentrically around an oral-aboral axis oral aboral

Nematocysts • specialized stinging organelles • found within cnidocytes (cells) • cnidocytes are located

Nematocysts • specialized stinging organelles • found within cnidocytes (cells) • cnidocytes are located in epidermis A cnidocyte with a nematocyst within it

Nematocysts • nematocysts are like “mini-harpoons” • cnidocil senses movement & acts like a

Nematocysts • nematocysts are like “mini-harpoons” • cnidocil senses movement & acts like a “trigger” • can inject poison, coil around prey, or be adhesive • functions: - prey capture; defense nematocyst cnidocil cnidocyte Undischarged Discharged

Colony formation • colony formation is common (colonial animals) • occurs via asexual reproduction

Colony formation • colony formation is common (colonial animals) • occurs via asexual reproduction (e. g. fission) • individual polyps are connected to one another by the GVC individual polyp

Physiology Feeding – nematocysts within cnidocytes – tentacles Digestion – extracellular (in GVC) –

Physiology Feeding – nematocysts within cnidocytes – tentacles Digestion – extracellular (in GVC) – intracellular (by gastrodermal cells) – incomplete system (no anus) Gas exchange & Excretion – these systems are absent

Physiology Nervous System – nerve net (no central nervous system= no brain) – sense

Physiology Nervous System – nerve net (no central nervous system= no brain) – sense organs – statocysts (equilibrium organs) – ocelli (photosensitive organs) Skeletal System – water in GVC acts as a hydrostatic skeleton

Physiology Reproduction Asexual – budding – longitudinal fission – pedal laceration (e. g. sea

Physiology Reproduction Asexual – budding – longitudinal fission – pedal laceration (e. g. sea anemones)

Physiology Reproduction Sexual – usually dioecious (separate sexes e. g. humans) – monoecious (both

Physiology Reproduction Sexual – usually dioecious (separate sexes e. g. humans) – monoecious (both male + female gonads in 1 individual) – results in Planula larva

Phylum Cnidaria Class Hydrozoa Class Scyphozoa Class Anthozoa

Phylum Cnidaria Class Hydrozoa Class Scyphozoa Class Anthozoa

Class Hydrozoa • medusa & polyp body forms Fire coral

Class Hydrozoa • medusa & polyp body forms Fire coral

Class Hydrozoa • medusa & polyp body forms • most are colonial colonies are

Class Hydrozoa • medusa & polyp body forms • most are colonial colonies are formed of individual zooids a single zooid

Class Hydrozoa • many of these colonies show polymorphism this is where there are

Class Hydrozoa • many of these colonies show polymorphism this is where there are several different types of polyps/zooid and each type is specialized for a different function e. g. gastrozooids = feeding polyps e. g. dactylzooids = defense polyps all the zooids within a colony are genetically identical these different zooids work together in the colony

Class Hydrozoa - a sessile colony showing polymorphism gastrozooid gonozooid entire colony

Class Hydrozoa - a sessile colony showing polymorphism gastrozooid gonozooid entire colony

Class Hydrozoa - a Portugese Man-o-war is a floating hydrozoan colony showing polymorphism pneumatophore

Class Hydrozoa - a Portugese Man-o-war is a floating hydrozoan colony showing polymorphism pneumatophore entire colony gastrozooid dactylzooid

Class Hydrozoa- life cycle sexual reproduction asexual reproduction

Class Hydrozoa- life cycle sexual reproduction asexual reproduction

Class Hydrozoa • Hydra is an example of a solitary, freshwater hydrozoan asexual reproduction

Class Hydrozoa • Hydra is an example of a solitary, freshwater hydrozoan asexual reproduction gonads bud

Class Scyphozoa • “true” jellyfish • medusa & polyp body forms • thick mesoglea

Class Scyphozoa • “true” jellyfish • medusa & polyp body forms • thick mesoglea

Class Scyphozoa- life cycle sperm egg ephyra strobila Adult medusa scyphistoma larva

Class Scyphozoa- life cycle sperm egg ephyra strobila Adult medusa scyphistoma larva

Class Anthozoa • polyp body form ONLY • all marine

Class Anthozoa • polyp body form ONLY • all marine

Class Anthozoa • some are colonial colonies are formed of individual zooids • some

Class Anthozoa • some are colonial colonies are formed of individual zooids • some are solitary

Class Anthozoa Sea anemones

Class Anthozoa Sea anemones

Class Anthozoa Soft Corals Sea pen Sea pansy

Class Anthozoa Soft Corals Sea pen Sea pansy

 Class Anthozoa Stony Corals

Class Anthozoa Stony Corals

Class Anthozoa- life cycle Sexual reproduction sperm egg larva

Class Anthozoa- life cycle Sexual reproduction sperm egg larva

Class Anthozoa- life cycle asexual reproduction fission pedal laceration fission

Class Anthozoa- life cycle asexual reproduction fission pedal laceration fission

How does Cnidaria fit in? Cnidaria Porifera 3 classes: Hydrozoa, Scyphozoa, Anthozoa 2 body

How does Cnidaria fit in? Cnidaria Porifera 3 classes: Hydrozoa, Scyphozoa, Anthozoa 2 body types: polyp, medusa diploblastic 3 body types tissue level choanocytes of organization cellular level of organization Blastula stage heterotrophic multicellular eukaryote unknown common ancestor

Symbiosis Mutualism – • Corals contain endosymbiotic algae called zooxanthellae • the zooxanthellae photosynthesize

Symbiosis Mutualism – • Corals contain endosymbiotic algae called zooxanthellae • the zooxanthellae photosynthesize and provide food for the coral while the coral provides a safe home zooxanthellae

Symbiosis Mutualism – • Many species of anemone fish (clown fish) live within anemones

Symbiosis Mutualism – • Many species of anemone fish (clown fish) live within anemones and are immune to their stinging nematocysts • the fish may lure in other fish for the anemone to capture and eat, while the anemone provides protection and a home

Coral Reefs What are they? • stony corals lay down a calcium carbonate skeleton

Coral Reefs What are they? • stony corals lay down a calcium carbonate skeleton • these skeletons are laid down on top of one another and over thousands of years, form large calcium carbonate structures • these large structures, along with the plants and animals that inhabit them, are known as coral reefs Where do they form? • in optimal conditions for their zooxanthellae shallow, warm, nutrient-poor waters

Importance of Coral Reefs • one of the most productive ecosystems although the water

Importance of Coral Reefs • one of the most productive ecosystems although the water is nutrient-poor • “hot spots” for biodiversity

Threats to Coral Reefs • over-enrichment of nutrients from sewage and agricultural run-off •

Threats to Coral Reefs • over-enrichment of nutrients from sewage and agricultural run-off • overfishing of herbivorous fish • global warming (leads to coral bleaching where corals expel their zooxanthellae)