Animal diversty Flashcards
Next points are what makes an animal
Multicellular
○ Super group phylogeny of eukaryotes
○ Supergroup opisthokonta includes all multicellular animals, fingu and a number of phyla of what were once considered protozoa
○ The animals have been treated histroyclly as a kingdom
○ Paramecium - some protists are related to us
○ Animals are multicellular but this isnt didtinct to us because plants and fungi are also multicellkular
The closest non multicellular ancestor to us are choanoflaggelates - not multicellular but hangout in groups that work together
Have a head?
○ Animals are often described their symmetry
○ Body symmetry is size and shape of body/parts along an axis or plane
○ Many animals have heads but that doesn’t make it an animal
○ Theres bilateral symmetry in which theres a head and tail end
○ Many naimals don’t have that and instead have radial symmetry like rounded
○ Symmetry of aniamsl differs but they have some kind of symmetry
Still not narrowing them down
Extracellular matrix
○ Extracellular matrix of animals are imprtant
○ They hold the cells togetehr in multicellular organisms
○ Form a scaffolding that becomes minerlized and forms bones, shells or spicules of various animals
○ The extracellular matrix also plays a role in dveelpopment of animals from sponges to humans
○ Allows for complex multicellularity
○ Animals procude collagen which is simply unqiue to animals
○ 4 Kinds of molecuels make up the extracellular matrix
§ Collagen - long proteins that form a triple helix to form fibres with high tensile strength - primary protein in connective tissue
§ Proteoglycans - form the highly viscous fluid of mucus and extracellular matrix
§ Glycoporteins - large unbracnnhes molecules that resist compression; return to original shape after being squished
Integrin - the molecule that connects the extracellular matrix to the outside of the cells
Gastrulation
○ Early embryolopgical devlopment
○ Development beggiing shortly after the zygote is distinct in animals
○ The development of gastrula from hallow ball of cells
○ Germ tissue develps during this time which differintates into major tissue types of the body
○ Gasturla becomes the opening of a mouth or anus
The hallow ball can have a liquid sometimes - internal cavity with fluid known as coelom
Body Cavity
○ Body cavity often, the coelom
○ Internal spaces, tissue layers and embryonic dveelopment is impriatnt for orgnaizing higher animals
○ Bilateria all have abody cavity of some kind
○ Acolomates do not have a cavity outside of digestive tract
○ Pseudocoelomates have a body cavity but no extra tissue
○ Coleomates have body cavity and are surrounded by tissue
○ Fluid filled cavities can act as a hydrostatic skeleton or allow internal organs to exist free from the body wall
○ Hydrostatic skeleton - soft body animals need soemthing to maintain their shape and something the muscles can work againstt - inetrnal coleim can resistc ompression which helps miantin strtuce and gives muscles something to work against
animal characteristics
- So animals are multicellular and produce collagen - theres lots of diversity in symmetry, gastrulation and presence of coelom
- Some morhpholgical characters are used to ogranize animals
- We have choanoflagellates which arent aniomals
- We have bilaterians - bilaterial symmetry
We have radiates which are animals with radial symmetry - includes the phyla poriferians and cnidarians
Bilaterians and Radiates
Animals seperated into two diff groups
- We have bilaterians - bilaterial symmetry - We have radiates which are animals with radial symmetry - includes the phyla poriferians and cnidarian
these groups further split into seperate groups
Radiates: porifera and cnidaria phylums
○ Porifera - sponges:
§ Porifera phylum
§ 5000 species
§ Primarily marine
§ Sponges are widespread in oceans and have a simple anatomic organization - no tissues
§ Choanocyte is a specialized cell
§ They feed by drawing water containg food particles and discolved organic moelcuels into their interiors
§ Choanocytes act as the filter clearing water of particles they can feed on
§ Simple - bunch of cells embedded in matrix they create that is made up of collgen and some other molecules
○ Cnidaria - Jellyfish, Anemone and Corals
§ More than 9k species
§ In marine and freshwater
§ All cnidarians have:
□ radials symmetry
□ A mouth surrounded by tentcalces with stiniging cnidocytes
□ Incomplete gut - only mouth no anus
□ Two tissue layers (endodermis and epidermis)
□ Cell free mesoglea surrounded by epidermis on outside and endodermis on sinsdie
§ Two types of bodues that most go through as they mature:
□ Polyp - gut in the centre and everuthing comes in one way - many tenticles
□ Then transofrm into medua or jellywish - they have mouth still by tenticles
§ Unlike sponges cnidarians:
□ Have epithelial lined gut (sponges are empty only cells)
□ Have radial symmetry
□ Have tissues and organs
□ Reater dievrsity of cell types inclduing the specilzed stinging cells (cnidiocytes)
□ Cnidaria are predators (sponges are just filters)
§ Corals do not make medusas
Bilateria
○ Aniamls with head and tail ends
○ Split into two groups: protostome and deuterostome
○ Bilateria - cephalization - development of a head
§ Distinct head nad tail
§ Clustering of sense organs on forward facing or anterior end
§ Often an anus at posterior end
§ Mouth at anteriro
§ Mouth not always at anterior - in flatworms its at the middle of body
○ Protostomes - invaginatio of vlastula to form gastrula creates the mouth first and anus later
In deutrostomes, the mouth is second - we are deautrostomes
Lophotrochozoa
One group of protosomes (other is ecdysozoa)
□ These make up almost half of all animal phyla □ Annelid worms and mollusks in this group □ Lopophre - tentalce linded organ for filtered feeding □ Trochophore - type of larva or jeanulize stages in womrs and molluscs □ Zoan - indicates that athese are aniamls □ Annelids worms - segmented round worms ® Phylum annelida: ® Segmented round worms ® More than 22k species ® Common in all habitats ® Coelom imprtant for hydrostatic skelton ® Septa seperates body segments ® Longitudinal and circular muscls surroudning the body ® Complete gut ® Well differentiated head and often with appendeges for movement (parapodia) or bristles (setae) ® Metamerism (repeating segmeneted body) allows greater complexity - independent movement of each segment - requires complex nervous system - if one segemnt inkured the aniaml can still function □ Phylum mollusca: ® 100k species ® Includes snails, slugs, squid etc, ® Snails or gastorpoda can be found in terrestrial, marine and freshwater ® Cepholopda are in marina only ® Bivalvia are in all as well ® They need moisture, shelter and calcium in soil ® Molluscs are distinguished by their mantle (shell) ® Molluscs developp from a distinctive larva called a trochophore that has a tuft of cilia at its top and additional cilia bands around its middle ® Gastropods: three main classes - they are assymetrical bodies with well developed head - often with a single shell - assymtreical because organs on one side and shell on other kind of ® Cephalopods: well developed head withr ings of arms/tentacles; muscular siphon - hunters - lost shell ® Bivalves: bivalia have shell with two valves or basically two shells - held together by msucle - there is reduced head - these are critical to clean water
Lophotrochozoa (group in protosomes which are in the bilateral animals) - made up almost half of animal phyla - annelid woms and molluscs
Ecdysozoa
group in protosomes (which are part of bilateral aniamls)
□ Ecdysis = molting an outer covering; many undergo metaphorphiss - shed skins □ Phylum Nematoda - unsegmented round womrs: ® 25k species ® Most numberous of all aniamsl ® Found in all habitats ® Imprtant part of soil communities and reach 2000k inidvduals per 100g of dry soil ® C.elegans ® Breakdown undigested material - impratnt for productive soil ® Some are parasites - most humans live in areas with persistent nematode parasittes - heartwrom which infects pets, hookworm attaches to dog, and rootknot roundworm □ Phylum Tardigrada: ® 1300 species ® Found in soils, sediments, leaf litter, mosses, and lichens - anywehre it egts wet ® Small - less than 1 mm long ® Live in water film around mosses and lichens ® Elongates, cylindrical or oval, body is unsegmented ® Four pairs of short stubby unjointed legs with 4-8 claws ® Body covered by non chitinous cuticle that is molted four or more times ® Defing charcteric is mouth with stylet ® Mouth leads to muscular pharynx adapted for sucking ® Two stylets portrude to pierce prey or alls of plant cells to allow then to suck juices ® They are incredibly resistant □ Phhylum arthorpoda: ® Massive phylum ® Dominant in life ® Chelicerata - spiders ® Myriapoda - centipedes ® Crustacea - lobsters - dominat in sea Hexapoda - insects - domiant in land ® Different segemented body - segemented become fused together and become functionally organized into different parts - theres the head, thorax and abdomen ® Also have to shed skin to get larger ® 1.2 mil species ® Found in all habitats ® Appendages are jointed ® Exoskelton with chitin ® Metamorphasis - they go through drastic body changes as they mature ® Modifcations and evolution of appendaged on the anterior segemnts of arthorpods produce the groups we see ® In terms of species, arthorpods are most succesful organsms on earth ® They occupy an extremely wide range of habitats and some have remarkable tolerance of adverse conditions ® The exoskelton is reason for dievristy - its highly protective without sacfircing mobility - several layers - contains chitin, a tough resistant nitrogenous polysacchardie that insuble in water, alkalis, and weak acids, in crustaceans the outer layer has calcium salts - the exoskleton allows them to change shape ® Because the skelton cant be enlarged it has to be replaced by a alrger one - process called ecdysis (molting) - arthrpods molt 4-7 times before reaching adulthood - molting is harmonly controlled - diff stages of development can be diff thus reducing intraspecific compeltion Arthropods also have a variety of highly developed sense organs - the combo of visual, olfactory, tactile and balance senses makes them very alert to their envinrmnt - the compound eye is senstive to motion
Deuterostome
§ Deuterstomes are the second major group of bilaterians - includes humans and other chordates and acorn woms and seastars
§ The two major phyla are echinodermata and chrodata
□ Echinodermata:
® Return to radial symmetry
® 7k species include urhcins, sea stars, sea cucumbers
® Found only in the worlds oceans
® Keystone species - meaning their presence of predation or feeidng on large alage acts to maintain biodiversty of habitat
® Still part of bilaterians because larvan stage have bilateral symmetry
® Have pentaradial symmetry (5folds) and a water vascular system that enables tube feet to faciliate movement
® Water vascular system: hydrlic system that uses muscular pressure to coelom - ampulla are muscular sacks that hold fluid above the podia - contraction forces fluid into poda and stiffens them for walking
□ Chordata and vertebrates:
® More than 81k living species
® Subphylum vertebrata exclude protochordates - theres 64k of them and half are bony fishes
® Chordates have the following shared characertics: notochord, dorsal tubular nerve chord, pharyngeal pouches, endostyle or thryoid gland and postanal tail
® There are three major subdivisions: cranitia or vertebra, tunicata, and cephalochordata
® Notochord found in all which is cartilgnous rod - in all embryonic and some adults - serves as endoskeltal structural element and in large vertebrates is precursor to vertbral colum (backbone) - provides directional signaling to surrounding tissues during develppment - has elastic sping like propoerties to faliciate movement
® Subphylum vertebrata or Craniata:
◊ Aniamls with heads and skulls, vertebrae and spinal cord and a lot of things that we have in common with fish, frogs and flamingos
◊ Generally known as vertrebrates but craniates is more appropriate because they have head with brain while agnathans lack vertebrae
◊ Notochord, dorsal nerve chord, pharyngeal pouches and postanal tail - all present in some stage of dveelopment
◊ Endoskeleton consisting of vertebral column, limb grdiles, two pairs of jonted appendages and a head skeleteon
◊ Many unique layers of tissue in skin - mods of skin characetrics of classes like glands, scales, feathers, horns
◊ Muscular perforates pharynx
◊ Many muscles attached to skeleton for movement
◊ Ventral hear with red blood cells
◊ Complete digestive system from ventral to spinal column
◊ Well developed coleom mostly filled with viscera
◊ Excretory system of paired kidneys with ducts to cloca or anal region
◊ Differentaited brain
◊ Endcorine system of ductless galnds - hromones into blood
◊ Inidivdual producing eitehr spemr or eggs - each paired with gonads and ducts leading to cloaca or special anal openings
