Bio Animal Phylogeny

Colonial Choanoflagellate

Common ancestor

Porifera

No tissues(or organs), no symmetry, Acoelomate, Hard skeletal elements called spicules and elastic fibers, filter feed, sessile, marine, asexual-external and internal budding, sexual-sequential hermaphrodites, flagellated swimming larvae, lack nervous digestive and circulatory systems, all transport happens via diffusion.

Feed using filter feeding - Porifera have choanocytes, “collar cells,” which move water that enters the Spongocoel “sponge cavities” through the pores. Food moves into the choanocyte that is then absorbed by the Amoebocyte which digests and transports it (5x body volume/sec). Can be carnivorous.

Interesting fact - chemical defense mechanism to protect from predators and microorganisms has been use by humans to fight cancer and strains of Streptococcus (bioutilization).

spicules

microscopic needle-like structural components made of silica and calcium carbonate

Sessile

don’t move

Marine

live in salt water

hermaphrodites

animals that have both male and female sexual organs

Gemmules

Dormant embryonic cells produced by freshwater sponges

Choanocyte

Collar cell that has “hairs” that push food through it

Amoebocyte

motile amoeba like cells that digest and move food around in organisms

Cnidarians

Largest group of non-bilaterians, Diploblastic, radial symmetry, polyp and medusa, spawn with the moon phases, asexual-budding and fragmentation, sexual-medusae produce polyps. Either form can be dominate and some only have polyps and some only medusae.

Feeding - tentacles capture and push prey into gastrovascular cavity. Cnidocytes with nematocyts to stingand entangle prey. There is no centralized brain, so the nematocyst is triggered by an external structure

Polyp

sessile form of cnidarians

Medusa

Motile form of cnidarians

Cnidocytes

cells used for capture and defense

nematocysts

organelles that contain stinging thread to penetrate prey

Gastrovascular cavity

Space for digestion, circulation, gas exchange, and a hydrostatic skeleton

Hydrostatic skeleton

flexible cavity around muscles that provide structural support

Portuguese man o’ war

Not a jellyfish, but part of cnidaria. Colonian organism many of multiple polyps that function like a single animal. There are two species and their tentacles can sting whether or not they are attached.

Anthozoa

Subphylum of cnidaria. Occur only as polyps. Have photosynthetic dinoflagelates living in their tissues. These species get bleached when environmental stresses cause them to remove their zooxanthelle and they cannot reattach.

zooxanthellae

Photosynthetic single celled organisms that have a endosymbiotic relationship with anthozoans.

Protostomia

Clade that contains Lophotrochozoans(trochophore larva) and ecdyozans(molting exoskeletons)

Deuterostomia

Clade, triploblastic organisms where the blastopore becomes the mouth

Echinodermata

sea stars, brittle stars, sea urchins, and sea cucumbers, most are bilaterally symmetrical the larvae, marine only habitat, CaCO3 endoskeleton, invertebrates

Water vascular system - network of water filled canals which preform: internal support, circulation, respiration, locomotion feeling. Keystone species. Many are very sticky

Endoskeleton

Chordates

Part of the deuterostomia clade, developed a notochord. Include subphylums lancelets, tunicates, and vertebrates

Key characteristics: notochord, dorsal hollow nerve chord

Notochord

present in chordate embryos, longitudinal mesoderm structure that is composed of large fluid-filled cells. Function: site of muscle attachment, signals surrounding tissue during development, provide structural support.

Hollow nerve chord

derived from the ectoderm

pharyngeal slits

derived from the ectoderm, retained-used for suspension feeding or lost/modified into gills and parts of the head neck area.

muscular Post anal tail

vary in length and function, large are for locomotion and can be specialized. Absent/reduced can be lost during development.

Cephalochordata

35 species, mostly marine suspension feeders, small bodies, weak swimmers, gas exchange via diffusion, notochord extends length of body, most basal chordates.

benthic

lowest levels in a body of water

Urochordata (Tunicates)

Marine suspension feeders. most adults are sessile(some are pelagic)

Body: two siphons, full digestive tract, tunic(shell like structure) made of cellulose. Solitary ones are sexual and colonial ones are hemaphrodites

Larvae have all characteristics, adults only have a gill basket \

pelagic

open sea away from the coast

Vertibrates

Key traits: Vertebral column(part of skeleton, replaces notochord), Rigid endoskeleton, anterior skull with large brain, organs suspended in coelom, closed circulatory system, most have 4 Hox gene clusters(2 times as many as lancelets and tunicates)

Cyclostomata

Class Myxini - Clade within vertebrate, jawless, only jawless vertebra to survive past the Devonian period, marine bottom dwellers, weak circulatory system, partial skull, no stomach, cartilage skeleton

Use slime for defense - fill predatory fish digestive system with mucusy slime

Class Petromyzontida - marine and freshwater scavengers, some parasites, true skull, distinct vertebrae

Gnathostomata

Clade within vertebrate, have teeth and jaws which allows for predation, teeth was crucial for diversity, break up food for digestion, probably derived skeletal rods between anterior gill slits.

Duplicated hox developmental genes. Forebrain enlarged for better senses.

Chondrichthyes

Class within gnathostomata, aquatic, mobile and streamlined, dorsal fins for stabilization, pectoral fins and pelvic fins for multiple functions, caudal fin for propulsion and turning. Teeth aren’t anchored, Cartilage skeleton, muscles for movement, oil-filled liver to stay afloat, two chamber heart for circulation, more water into mouth and gills, continuously swim for gas exchange, sexual and some have live birth.

oil filled liver

A natural buoyancy control adaptation

denticles

structure on shark skin that make it rough, provide better aerodynamics, and prevent other organisms from growing on them

Osteichthyes

Clade, swim bladder, scale covered slimy skin, operculum, ossified endoskeleton, largest clade of vertebrates, sexual reproduction, some hermaphrodites and some paraphrodites.

Groups - ray-finned fishes, lobe-finned fishes(layer of muscle surrounds rod-shaped bones in petrol and pelvic fins), and lung fishes(gulp air into lungs connected to the pharynx)

lobe-limbed vertebrates

vertebrates with specialized limbs

Tetrapods

Four feet(some lost them), amphibians, amniotes, and mammals, some are extinct(dinosaurs), evolved 375 mya from lobe-finned fish

Transitioned to land during the Devonian period. Many of the transition species went extinct during the Devonian period. Adaption to air: desiccation resistance(body and eggs), respiration(lung and ribs, some gills, cutaneous), sensory input. Adaptation to gravity: locomotion(bones, girdles, digits), supportive spine. Adaptation to air: feeding(skull, neck, jaws, teeth, and tongues), reproduction

Lobe-finned fish evolved into lobe-limbed vertebrates.

Most have necks and ribs

cutaneous

relating to or affecting skin

Amphibia

class within tetrapoda

salamanders frogs toads and caecilians. Live in semi-aquatic environments and require moisture. Respire with lungs and skin. Larvae have gills(some adults). Only sexual reproduction. External and internal fertilization. Lay eggs in water. Undergo metamorphosis(tadpoles → frogs).

Amphibian populations are declining. 1/3 are threatened or extinct. Causes: habitat loss, climate change, pollution(skin is delicate), chytrid fungus. Amphibians act as ecological indicatiors.

amniotes

developed amniotic eggs(laid on land or stay within mother).

Advantages: reduces dependance on aquatic environments, Hard or leather shells(reduces desiccation and provide protection), embryo has food and safety to advance in development before hatching.

Features: Amnion(fluid filled compartment that holds embryo, absorbs shock and keeps moist), Allantois(sac for disposal of waste products), chorion(gas exchange across membrane or shell), yolk sac(stores and provides nutrients for the developing embryo)

All of the features grow from the embryo.

Reptilia

Habitats: terrestrial and aquatic. waterproof skin, lungs for breathing, most are ectothermic, 3 chambered heart, sexual reproduction (some are parthenogenic). Some archosaurs have a 4 chambered heart

parthenogenisis

Egg fertilizes asexually.

Aves

Clade that includes birds. most species of any tetrapod group. endothermic and regulate temp metabolically. many are very smart. able to fly: fewer organs(no bladder, less ovaries, small gonads, toothless), light skeletons and keel for supporting wings, muscle coordination and vision, wings/feathers(light, strong, and made of keratin) Very costly!!

Mammalia

Class within amniotes. Three major groups(monotremes, marsupials, eutherians). aquatic and terrestrial. lived with dinosaurs and survived cretaceous extinction. endothermic(regulate their own body temp)

Key charateristics: mammary glands, hair for protection and insulation, sweat glands, four chambered hearts separating oxygenated and deoxygenated blood

Monotremes

Group within class mammalia. platypuses and echindnas. Lay eggs, suck fur from milk rather than nipples.

marsupials

Kangaroos, koalas, wombats, Tasmanians devils. Australia and americas. fill the role of eutherians where they are absent. complete embryonic development in mothers pouch.

Eutherians

diverged from the breaking up of continents. filled gap left by dinosaurs. complex placenta. long pregnancy

Primates

order within mammalia and eutherians. wet nosed and dry nosed. early primates were tree dwellers. Grasping hands, large brain - short jaws, forward looking eyes, flat nails on digits, complex social behavior.

Humans

split from chimps in Africa. 20 extinct hominid species. genome is 1% different from chimps and include 19 regulatory genes, upright and bipedal, large brains, small jaws, short digestive tract. Homo sapiens emerged 200,000 thousand years ago.

Lophotrochozoa

some have lophophores and trochophore larva while others had independent gains/losses.

Most diverse bilaterian clade

Lophophore

ring of ciliated tentacles for feeding

trochophore larva

cilia used for locomotion and feeding

Ectoprocta/Bryozoa

Phylum within lophotrochozoa

Colonial, found in marine and brackish water, sessile, external body makes a wall. One founder makes the colony but sexual reproduction is also there.

Platyhelminthes

Phylum within lophotrochozoa

Flatworms, free living scavengers, most are parasitic, coelomates, marine and fresh water as well as damp terrestrial, distinct head region, can be microscopic or 20m long, use diffusion for gas exchange.

Can live in multiple hosts

Trematoda

class of Platyhelminthes: Blood fluke, cause schistosomiasis, immunological camouflage, can live in humans for 40 years

Flukes live in blood vessels of the human intestine. They sexually reproduce and the eggs exit in human poop. The larvae infect snails which asexually reproduce which forms motile larvae which infect humans

schistosomiasis

pain, anemia, diarrhea, liver damage, kidney failure.

Syndermata/rotifera

Free swimming, sessile, colonial, pseudocelomates, live in freshwater and damp soil, microscopic, sexual reproduction

Have distinct organ systems and a complete gut.

Brachiopoda

phylum within lophotrochozoa, marine and attach to things via a stock, lophophore for feeding, come from the Paleozoic and mesozoic eras, coelomates

Annelida

Two groups; Polychaeta(marine, mobile, segmented bodies) and cilellata(reduced or no parapodia, earthworms and leeches), coelomates, live in marine freshwater and terrestrial habitats. Sexual reproduction with some hemaphrodites, asexual budding/regeneration can occur.

Most have repeated segments with repeated organs. Closed circulatory systems, gas exchange happens through diffusion.

Mollusca

phylum within lophotrochozoa, coelomates, body have a foot, mantle, visceral mass, radula, and an open circulotory system

Chitins

Group of mollusks, simple digestive and nervous systems, marine omnivores

gastropods

snails, slugs, limpets, etc, most are marine with some freshwater and land, one-piece shells, land snails and slugs have a mantle that creates lungs.

bivalves

clams, oysters, mussels, scallops, freshwater and marine, two shells with two adductor muscles, filter feed

Cephalopods

Squids, octopus, cuttlefish, aquatic, arms/tentcles with suckers, mantle forms a siphon from movement, shell can be internal or non-existent, complete brain and sense organs.

Endysozoa

Clade within the protostome clade, shed external coats which provide protection and structural support which is excreted by the epidermis. All arthropods developed the same hot genes for the cuticle.

Nematoda

“Round worms“, within clade ecdysozoa, pseudocolomates, aqueous environments including animal tissue and blood vessels, reproduce sexually, important for decomposition and nutrient cycling, cause gastrointestinal problems in humans, used as a model animal

Parasites: can live in multiple hosts(plants, insects, and humans), can enter the human intestine and cause trichinosis

tardigrada

“water bears“, ecdysozoans, live in water and on other organisms, coelomates, pair appendages, lost many hot genes, very small, diffusion for gas exchange, can survive in many extreme contditions.

arthropoda

Ecdysozoa phylum, paired appendages, four extant groups(crustaceans, hexapods, chelicerates, and myriapods), coelomates, live everywhere, reproduce sexually, open circulatory systems

Adapted to land using segmentation, rigid skeletons, jointed appendages, small size, and wings. Many have developed head regions. Many metamorphisize.

Chelicerates

Spiders, scorpions, etc. Head has two pairs of pointy appendages to grab prey, two body segments.

Crusteceans

Mostly aquatic, three body regions, appendages are specialized

Myriapods

centi/mili pedes, mandables in mouth for chewing, biting, and capturing, long flexible bodies made of many segments.

Hexapods

insects, mandable mouthparts, three body regions, three pairs of wings, many have wings.

Metamorphosis

Infant does not look like adult.

Incomplete: terminal molt marks maturity

Complete: body changes form, adults are specialized for reproduction