Bio 2135 Questions

What is a functional anatomy approach in animals?(they face 4 issues)

What is a functional anatomy approach in animals?(they face 4 issues)

Coping with physical environment, finding food, avoiding become food(prey), and reproducing . (Ex: necturus, ctenoides scaber,casper,amphitrit and paludosus use gills to take oxygen from water.)

What are cornerstore themes?

Structure-function relationships(functional anatomy parts aiding the animal to survive)

What is a trait?

All characteristics animals have

What is an adaptation?

structure, physiological or biochemical mechanism, that is a product of evolution by natural selection and has adaptive significance(benefits fitness; based on different genotypes in DNA sequences).

How does the structure or mechanism work(cornerstore theme)?

reductionist approach. Ex: fireflies; glow in their abdomen, how does it work?

Why do animals possess the structures or mechanisms they have?

Adaptive significance, it allows gain insight if its a trait or an adaptation.(determined through experiments) Ex: firefly ; because adaptation, maybe communication within species(mating?), attracting food,etc..

What are the limits on natural selection?

traits do not occur in isolation(each need to work for animal to survive), phylogeny(animals from descendants continue to carry trait although not necessary), genetic drift(bottleneck;overtime,small ranges of habitats so frequency differs)

What is phenotypic plasticity?

When phenotypic changes occur within an individual(ex: genotype does not change)

What is acclimatization?

A type of phenotypic plasticity, where changes in the structure or function in response to a change in the environment that occur in an individual in response to changes in the natural environment.(no change of genotype, usually reversible due to environment)

What is acclimation?

changes in a structure or function in vitro/experimental or laboratory setting.

What is developmental plasticity?

phenotypic differences(same genotype) that exist as a result of the environment during development. Ex: daphnies develop in lakes with predators have spikes(protection) whereas daphnies develop in lake without predators did not have any spikes.

What is centrality of the environment?

Plays an important roles and adaptations based on their environments.

• marine, fresh water, terrestrial, parasitic

• convergent evolution (ex: seals, penguins&tuna)

Whats a regulator/its role?

its what tries to maintain osmotic pressure in a consistent internal environment when external environment changes.

Whats a conformer?

as the osmotic pressure changes, so does the animals bodily fluids.

What is scaling relationships?

relationships between morphology or physiology and body size. There are some constraints on body sizes, which changes size of the animal( get knock effects)

What is isometric mean?

in direct proportion to their body size Ex: blood volume in vertabrates

What does allometric mean?

disproportionate relationship with body size.

What is isometric scaling?

there is a proportional relationship if b= +1(increases) or -1(decreases)

What is allometric scaling?

when metabolic rate decreases when body mass increases

How does evolution generate form and function?

by classification of organisms

What is Bauplan(body plan)?

set of morphological and developmental characteristics that shapes the biology of an animal.

How can you classify an animal?

• product of evolution

• can use features of the body plan to identify and classify animals

What is evolution?

change in gene frequencies over time(across generations). Occurs through natural selection ; variation of a trait/heritable /genetic) So, averagely, offspring vary mainly in directions favoured by existing environment(diff in fitness) survive and produce next generation(diff reproduction)

What’s an example of other mechanisms of evolution that do not lead to adaptation?

Genetic drift

What does natural selection do?

can only act upon the available variation. Ex: human bipedalism.

whats human bipedalism?

Quadruped→backbone forms arch with limbs as pillars; even distribution of weight. Ligaments sling from backbone holds viscera.(weight evenly distributed across 4 limbs, arch supported by the limbs each taking ¼ of the weight)

Biped→All weight on hind limbs and lower backbone; need sturdier lumbar and sacral vertabrate, cup-shaped pelvis. (hernias, lower back problems due to loose arch shaped, s shape spine, all weight on pelvis and spine.)

what do organisms represent for natural selection?

they represent a whole suite of interacting characteristics. Ex: scaling constraints on body size. When SA:V falls as animal size increases. This impacts processes relying on exchanges(water balance), and animal size is a compromise between conflicting requirements.

What occurs during osmorespiratory compromise at fish gills?

• diffusion is proportional to SA(fick equation)

• Gills structure is a compromise between the requirements for o2 uptake (by diffusion) and the need to minimize undesirable diffusion of water, ions.

• by maximizing the surface area for H2O intake, causes ions to come in causing osmosis forcing the H2O out resulting it to not be perfect.

Explain how natural selection can give rise to a trait that might be expected to reduce survival of individuals possessing it.

Reproductive fitness is what matters, not survival in the case of a peak hawk.

How does an animal develop?

• fusion of the haploid gametes gives fdiploid gamete

• cleavage gives rise to the blastomeres.

  • Partioning of cytoplasm into blastomeres

  • geometric doubling of cell number

  • holoblastic(complete) vs meroblastic (ex:zebrafish)

  • appearance of blastocoel

  • polarization-apperance of main body axis.

What does gastrulation do?

gives rise to gastrula with multiple distinct cell layers.:

-invagination: appearance of archenteron and blastopore.

• diploblastic vs triplonlastic embryo(has body cavity;coelm)

What’s the ectoderm?

epidermis and its derivatives, the nervous system.

What’s the mesoderm?

muscle,bones,connective tissue,circulatory system.

What’s the endoderm?

lining of the digestive tract and it’s associated organs.

What’s Hox genes(regulate development)?

homeobox-containing genes

180-nucleotide homeobox codes for 60-aa homeodomain

trascription factors; homeodomains binds to DNA.

What is symmetry in animals?

usually either radially or bilarerally symmetrical.

Whats bilateral symmetry and its advantages?

2 halves mirror image to each other. Advantages is that its good for directional mouvements allowing for sensory nerves and structures permitting a formation of a head/cephelisation. (more successful body plan)

• Has transverse(anterior and posterior end)

• Frontal section (ventral vs dorsal)

Whats radial symmetry?

faces the environment with the same face all the way around.(top and a bottom, no head)

What is segmentation?

many animals formed in serial repetition segments. (metameres or somites)

segments are repeated units that are strung together

What’s acoelomate?

where there is no body cavity(parenchyma)

The mesoderm becomes mass tissue named parenchyma

no openings, just solid

Whats hemocoel?

persistent blastocoel lacking peritoneum-comes from the mesoderm(basic body cavity, no digestive system)

hemocoel is between the mesoderm and digestive tract

muscle layers underneath ectoderm but not around the gut

What’s Eucoelomate ?

True coelm lined with mesodermal peritoneum

true body cavity, muscle layer underneath ectoderm but around the endoderm

• Mesenteries holds internal organs in place

• schizocoelous=splitting of mesodermal bands

• enterocoelous =coelm derived from outpocketings of the archenteron.

What’s protostomes?

first opening (blastopore becomes the mouth), spiral cleavage-occurs between 2 previous cells (determinate early on in development; each cell has a particular fate, if you loose the cell, you loose the character)

mesoderm split( you get 2 halves of an animal)

• coelm forms from schizocoeulous

exoskeleton, ventral nerve cord and dorsal heart

Ex: antropodes

Whats deuterostome?

2nd opening becomes the mouth, first one becomes the anus(blastopore).

radial and indeterminate clevage.(splits in half, you get twins)

mestoderm folds of archenteron form coelm

endoskeleton(covered by soft tissue), dorsal nerve cord and ventral heart.

Ex: cordates

What are key characteristics of chordates?

• Dorsal hollow nerve cord

• Notochord

• Muscular post anal tail

• Pharyngeal slits( slits in the tissue where water can move through) **Fundamental characteristics of chordates, hence we expect all animals under them to have these characteristics

Whats an example of a chordate?

Cephalochordata:

• it had larval stages showing 4 characteristics

• Adult form is sessile (not showing all characteristics)

What is differential reproduction?

Refers to the idea that animals that have a particular trait that benefits them in an environment will be more successful, and therefore leave more offspring than an animal who does not have that version of the trait

What’s an animal?

No cell wall,Multicellular, and HOX genes

What characteristics define animals?

• metazoans; multicellular

• monophyletic origin is likely from a colonial protist

• origin from a protozoan thats colonial (cells group together)

• simplest animals→ sponges just multicellular with specialized cells

What’s animal phyla?

Most successful based on number of known species are Arthropoda (million species),

Mollusca (85000 species) and Chordata (vertebrates, humans)

■ Platyhelminthes (flat worms), Nematoda (round worms) and Annelida (segmented worms)

● 20,000-30,000 species ea

What’s phylogeny based on?

• shared molecular and morphological characteristics

Compare Cladograms vs phylogenetic trees

•  Cladogram: branch links not meaningful

•  Phylogenetic tree: the branch links tell you how much change has occurred

Compare Branch points and sister lineages

•  Branch point is the point where ancestral species gives rise to new lineages

•  Sister lineages share a common ancestor → more closely related to each other

whats Basal taxon?

•  Is the original lineage that stems from the ancestral species, shows fewest

  derived traits

•  In this case sponges are the basal taxon

What’s a clade?

• includes ancestral species and all of its descendants (monophyletic)

• Animals as a whole is a monophyletic clade

Compare : Ancestral vs derived traits

Ancestral traits are traits that are present in all members of the clades

• Ex: true tissue is everything after eumetazoans, they are ALL multicellular though

• Distinguished on whether trait is present in ancestral species (ancestral) or only in lineage arising from the ancestral species (derived)

Whats the difference between homologous vs analogous traits?

Homologous traits are traits that are similar because of shared ancestry

○ Wing of a bat and bird
● Analogous trait is a trait shaped by convergent evolution

○ Wing of bee is analogous to bird wing because they have been shaped by convergent evolution

What are the advantages of having a coelm?

• Physiological efficiency – e.g. circulatory system, digestive tract

• Increased organ complexity and surface area; mesenteries for organization and

  protection

• Increased efficiency of locomotion?

  •  Use body cavity as hydrostatic skeleton

  •  Have more muscle layers

  • Supported by increases in number, diversity and size of eucoelomate animals

compare Protostome vs deuterostome?

Independent evolutionary events and that is supported by the fact that we see groups

with a mix of protostomes and deuterostomes
○ Muscle layer under outer covering AND around digestive tract (peristaltic contractions move

food)

Whats a basal metazoan

a) Phylum Porifera

Sponges (mostly marine) ➢ Simplest animals

•  Collection of specialized cells that work together

•  Differentiated cell types but no tissues → cells act independently ➢ No symmetry/ Many sizes

What are the structures of a basal metazoan?

•  Spongocoel → open space

• ○  Epidermis containing numerous pores

■ Outer layer → epidermis that surrounds the pores

• ○  Choanocytes (collar cells) → inner layer of cells that surrounds the spongocoel

  • Choanocytes have a single flagellum and the beating of that flagellum helps move water through the organism

  • Finger like projections that produce mucus and catches food particles in the water

• ○  Mesohyl (contains amoebocytes)

  • Gelatinous layer between choanocytes and epidermis

  • Amoebocytes → secrete the protein that serve as structure for the sponge. Secrete

    spicules like:

● Fibres of spongin, CaCO3 or silica (rigid structures)

○ Food digested by phagocytosis ➢ Motile larvae, sessile adults

○ Motile larvae to allow dispersion ➢ Water → pores → spongocoel

what’s a basal eumetazoan?

Eumetazoans

•  Derived trait – presence tissues

• Basal – diploblastic, radial symmetry

  • Phylum Ctenophora (comb jellies)

  • Phylum Cnidaria

•  Bilaterians – triploblastic, bilateral symmetry

  • The other animals that are not comb jelly and cnidaria fall under bilateria

  • More successful than basal Eumetazoans

•  Note : ALL THE THINGS WE WILL CONSIDER EXCEPT FOR PORIFERS ARE Eumetazoans

Whats the Phylum Cnidaria (basal eumetazoans)?

• Simple nervous system/ vary in size

• ○  Body plan

  • Diploblastic

    • ●  Epidermis from ectoderms and gastrodermis from endoderm

    • ●  Between them get mesoglea

  • Gastrovascular cavity with single opening

  • Tentacles armed with cnidocytes

    • ●  Within cnidocyte you get nematocyst which is a stinging capsule which has a thread that can b ejected when the cell is discharged

    • ●  prey/protection

Whats the shapes of basal eumetazoans?

•  Sessile polyps

  • ○  Attach to substrate through aboral end

  • ○  Cup shaped mouth and anus

  • ○  Opening to gastrovascular cavity surrounded by tentacles

  • ○  Radial symmetry

•  motile medusae

  • ○  Bell shape

  • ○  Single opening surrounded by tentacles

  • ○  Free-swimming

  • ○  Radial symmetry

What are the cell specializations of basal eumetazoans?

Epitheliomuscular cells for movement

• ●  Not true muscle cells, but muscle-like cells

• ●  Cells that contain microfilaments arranged into contractile apparatus allowing the

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animal to undergo contractile movement

● Work with neurons

• Cnidocytes (with nematocysts)

• Sensory and nerve cells forming simple nerve net (no brain)

• Enzymatic cells

● Gastrovascular cavity there rae cells that produce enzymes and release them into the gravity and get digestion, and then taken up by cells for further digestion

• Recognize stimuli and move towards it using coordinated contractile movements

• NEURONS AROSE HERE

What are the 3 classes of eumetazoans?

Scyphozoa – jellyfish ● Mostly medusa

• Hydrozoa – hydras ● Polyps

• Anthozoa – corals and sea anemones

  ●  Exoskeleton of CaCO3

  • ●  Only found as polyps

    ●  Purple dots → coral so new individual grow on the structures left behind and

    that’s what gives rise to coral reefs

    ●  Corals form relationship with zooxanthallae that are photosynthetic and are taken

    by coral

    • ○  Coral provides home for them

    • ○  They become food source for corals because it synthesizes

      carbohydrates the coral could use

    ●  Coral bleaching, they lose their colour cause they expel the zooxanthallae and

    don’t survive very well

Whats Ctenophora?(comb jellies of basal eumetazoans)

3) Bilaterian (most success)

0. ➢ Bilaterally symmetrical which leads to cephalization ➢ Animals more active, directed coordinated movement ➢ Derived traits

   • ○  Cephalization

     • Presence of a head

     • Advantage for directed movement

   • ○  Triploblastic

1. ■ Mesoderm
   ○ Organ level of complexity

   ○ Active
   

What are the three classes of ctenophora?

•  Lophotrochozoa (grouped based on molecular evidence)

  • Some of them lack a body cavity, some have a hemocoel, some have a true coelom,

    some protostome, some deuterostome

  • A clade of invertebrates with a wide range of body forms

  • Lophophore – crown of ciliated tentacles for feeding

  • Trochophore – a distinctive larval stage

• ○  Ecdysozoa

  • Invertebrates, named for moulting of hard exoskeleton (ecdysis)

  • Stiff outer covering (cuticle) that they shed through molting to grow

  • Molecular data

• ○  Deuterostomia

■ Invertebrates and vertebrates (chordates) , named for deuterostome development

Whats in the Phylum acoela (basal bilateria)?

Deutertomi Bilaterian

➢ Note: Ectoprocta & Brachiopoda (Clade Lophotrochozoa) are also deuterostomes ➢ Deuterostome ecoelmates

Whats the Phylum Echinodermata?

•  Larvae are bilaterally symmetrical

• ○  Water vascular system and tube feet

• ○  Sea stars, sea urchins, sea cucumbers

• ○  Don’t have a head

• ○  Lack a brain

• ○  Bilateral symmetry but as adults they are radial symmetry

• ○  Mode of locomotion is based on a water vascular system

• ○  Draws in water through its dorsal side and moves it into the vascular system and uses water

  pressure to extend and retract the feet

Whats the Phylum Chordata?

derived traits

• Notochord

  • ●  Under dorsal nerve chord

  • ●  Provides shape and support

  • ●  Consists of large cells wrapped in CT

• Dorsal, hollow nerve cord

  • ●  Usually solid nerve cord it is only whole in pylum chordata

  • ●  It forms as a plate of ectoderm that rolls up into a tube and that tube develops into spinal cord and brain

    DISTINCT TO CHORDATA

• Pharyngeal slits

  ●  Food → mouth → pharynx → expel the water through pharyngeal slits

  • ●  Internal filter feeding

    ●  In fish they become gill slits

• Endostyle/thyroid gland

● Collection of cells associated with the pharynx that produces a sticky mucus that

helps with filter feeding by catching food particles ■ Muscular post-anal tail

● Digestive tract ends part way through the animal leaving a tail that is used for locomotion

What are vertabrates?

Derived traits

●  Skull, and backbone composed of vertebrae

Group of cells that forms on the dorsal nerve chord and gives rise to the skull, NS structures, adrenal gland, etc.

●  Notochord disappears in the mature animal but there are remnants between the discs of the vertebrae

• ●  Notochord only apparent in early development

  ●  Endostyle gland becomes thyroid gland in vertebrates

  ●  Vertebrae is a structural feature that surrounds the spinal chord

  ●  Basal vertebrates

  ○  Hagfish (marine, lck jaws) and lamprey

  ○  Vertebrae is not complete, so notochord is pretty important

  ○  HAGFISH PRODUCE A LOT OF slime to protect themselves from

  • predation

Whats Gnathostomes?

Derived traits ● Jaws

○ The skeletal rods are what gave rise to the jaws

• ●  Enlargement of forebrain

  ○ Forebrain becomes larger and elaborate to support sensory capacity for vision and smell

  ○ More complex brains

• ●  One of the sensory structures in aquatic gnathostomes is Lateral line system

  ○ System of mechanoreceptors present on the lateral line of the fish that allows them to detect water movement

● Basal gnathostomes

Chondrichthyes
■ Sharks, rays

Whats Osteichthyans?

• Derived traits

  • ●  Bony skeleton

  • ●  Lung or equivalent (swimbladder)

• Rayfin fish (actinopterygii) vs lob-finned fish (fleshy fins) (lungfish ex)

  • ●  Lungfish can drown

  • ●  Lungfish air breathers

• Rayfinned fish are model species

  • ●  Small

  • ●  Large numbers

  • ●  Short generation time

  • ●  Sexual maturity at 3 months

  • ●  It can heal itself (can heal its heart)

• Rayfinned fish are the basal osteichthyans

Whats Tetrapods?

Derived traits

• ●  Limbs with digits

• ●  Neck

○ Frog neck not obvious but still has it

● Absence of gills in adults
○ You can have gills in developmental stage

● Land animals
■ Basal tetrapods are amphibians

Whats Aminotes?

Amniotic egg with extra embryonic membranes (amnion, chorion, yolk sac and allantois) ● allows development in a terrestrial environment

■ Other traits that favour success on land: ● thicker, less permeable skin

○ Reduce water loss ● ventilation of lungs via ribs

○ Rib cage expands drawing air into the lungs ● stronger jaws & muscular tongue

○ Enables eating on land without having water ● nitrogen excretion that allows for water conservation

○ Allows it to excrete nitrogenous waste without excreting water

• Fully terrestrial environment

• Embryo surrounded by 4 membranes:

  • 1) amnion: Surrounds the embryo most closely and it provides a cushion protective membrane

  •  2) chorion: Surrounds the whole thing

  •  3) yolk sac: Surrounds yolk

  •  4) allantois: Sac where waste is deposited

  • ●  Vascularization between the membranes which contributes to gas exchange

    between embryo and environment

Whats a replitilia?

• Tuataras, turtles, squamates (lizards & snakes), crocodilians, birds

• ●  Birds have feathers which are important for flight and insulation cause they are

  endothermic. They also lost their bladder to keep them light.

• ●  In birds, derived traits include wings, feathers, loss of bladder

What are mammals?

Derived traits

○ Mammary glands, hair (as well as sweat glands), differentiated teeth (different types of teeths with different functions)

● 3 groups

• ○  Echidna and platypus which are mammals that lay eggs

• ○  Marcupials

• ○  Placental mammals

Whats Ecdysozo Bilaterian?

a) Phylum Nematoda (round worms)

0. ○ Hemocoel body plan
   ■ There is a hemocoel which is fluid filled cavity

   • ○  Clade Ecdysozoa

   • ○  Body plan

     • Hemocoel – Muscle layer under body covering but not around digestive tract

     • Ectoderm

     • Digestive tract with mouth and anus

   ● In this phylum we don’t have GC we have digestive tract

   • Mesoderm is found as a layer of muscle under the body covering

     • ●  Between that and the digestive tract is the hemocoel

     • ●  Hemocoel is basically a persistent blastocele

   • Fluid in hemocoel serves as circulatory system

   • Advantages – cushions internal organs, space for organ systems, increased freedom of

     movement

   • Advantages of Body cavity

9

● Cushions organs

10

• ●  Simple circulatory system (fluid sloshes around as animal moves moving O2 and nutrients)

• ●  Used as a hydrostatic skeleton making movement more efficient

What’s roundworms?

• Free-living forms, many parasitic species (e.g. Trichinella spiralis - trichinosis)

• Caenorhabditis elegans – model species

  • ●  C-elegans

  • ●  Small number of cells

  • ●  Developmental pathway has been mapped out from early times

○ Scientists can follow the pathway of each of those cells

• ●  Simple NS so you can easily make connection regarding the NS and behaviour

• ●  Lives anywhere

• ●  Transparent easy to follow what is going on

• ●  Similar characteristics to humans

• ○  Most organisms carry nematodes as parasites

• ○  Pinworms, hookworms, ringworms

Whats phylum anthropoda?

Protostome eucoelomates
■ Ventral nerve chord and dorsal heart

○ Body cavity in adult is a hemocoel
■ fluid -filled hemocoel filled with hemolymph

○ Cuticle that sheds is strong and flexible ■ Contributes to their success

• ○  Protest from predators and water loss

• ○  Segmented body so cuticle is flexible

• ○  Body plan

  • Protostome eucoelomates but in adults, main body cavity is a hemocoel

  • Segmented bodies with chitinous cuticle (exoskeleton)

  • Paired jointed appendages, often highly modified

● Effective locomotion

have 3 major lineeages : Chelicerates,Myriapods,and Pancrustaceans

What are chelicerates?

•  Arachnids (spiders, ticks, mites, scorpions) and horseshoe crabs

• ●  Chelicerae for feeding

• ●  Cephalothorax, abdomen, 4 pairs walking legs (no antennae)

• ●  Fusion of segments to form

○ Cephalothorax (anterior part of the body including head and thorax) ○ Abdomen

• ●  They have pedipalps which are used in reproduction, sensory, feeding

• ●  Mouth is called chelicerae → they are like pincher mouths

What are myriapods?

• ●  Centipedes – carnivores, 1 pair of legs/segment ○ Venom

• ●  Millipedes – herbivores, 2 pairs of legs/segment

○ More feet

What are Pancrustaceans?

•  3 main body parts: Head, thorax, abdomen

•  appendages often highly specialized

•  Crustaceans – isopods, decapods (used as food, crab and shrimp, mineralized

  shell), copepods & krill (small and are at bases of of food chain), barnacles (mineralized shell, sessile)

  •  2 pairs of antenna

  •  Multiple branched appendages → biramous (ex: lobster claw)

  •  Most crustaceans are aquatic mostly marine

•  Insects – Drosophila melanogaster is a model species

  •  Antena

  •  Modified mouth parts

  •  3 pairs of legs

  •  Wings are a separate appendage

  •  Uniramous appendages

  •  Metamorphosis

1) incomplete metamorphosis

• Larvae is just mini version of adult

2) complete metamorphosis

•  Different adult

•  Specialized for reproduction

• Butterflies

What are lophptorchozoa ?

0. Phylum Platyhelminthes (flatworms)

   • ○  Clade Lophotrochozoa

   • ○  Acoelomate body plan

   • ○  Adult

1. ■ Mesoderm is Parenchyma

   • ○  Small

   • ○  Dorsal and ventral flat

   ■ Good because cells are close to environment for gas exchange and close to gastrovascular cavity for nutrients
   ■ Take up nutrients and do gas exchange by diffusion

What’s the body plan of lophptorchozoa ?

■ Triploblastic

■ Acoelomate – solid body

•  Lack a coelum

•  No body cavity they are solid

•  Gastrovascular cavity

•  Lack dedicated organs

•  No circulatory system

•  Nervous system with sensory receptors

  • More developed than cnidarians

  • Have a head

• True Muscle

• Excretory system (protonephridia)

■ System for collecting excess water and eliminating it from the animal

• ○  One opening to GC, mouth anus

• ○  Several groups

■ Turbellaria – generally free-living and marine; includes planarians (freshwater)

● See all traits of flat worms

What’s a trematoda?

flukes (parasitic)
■ See most traits, but instead of external environment they live in hosts

What’s a cestoda?

tapeworms (parasitic)

• Lack most features of flat worms, no GC, no brain, some sensory systems, very

  simplified

• Digestive tracts of vertebrates

• Scolex attaches to digestive tract

• Rest of their body is a string of reproductive sacks and they shed those into

  digestive tract

• Proglottid

• Survive without a digestive system cause they are bathed in nutrient fluid in host

What are mollusca?

• Protostome eucoelmates

• Clade Lophotrochozoa

• Body plan

■ Ventral nerve cord and dorsal heart

■ 3 main body parts

•  Muscular foot using for locomotion

• Visceral mass, all of the organs

• Mantle: layer of tissue on top of the viscera and underneath the shall (it is

  what secretes the shell)

• Where a shell is present, it is secreted by the mantle (CaCO3)

• Radula – rasping organ used in feeding

■ Ribbon like structure that is used to get food

● Radular teeth that is made of chitin

○ Teeth 60x stronger than steel

• Mantle forms cavity that has the gas exchange organ

• Have trochophore larva

• Several classes, including:

What’s Polyplacophora?

Chitons

● Rock hugging molluscs

Whats a Gastropoda?

● Snails and slugs

what’s Bivalvia?

• Clams, oysters, mussels and scallops

• Shell is in 2 halves connected by a hinge

• Sessile

What’s a Cephalapoda?

● Squid, octopus, cuttlefish, chambered nautilus

○ Giant squid (Architeuthis dux) and colossal squid (Mesonychoteuthis hamiltoni) are largest invertebrates

● Squid and octopus have the most complex brains and sensory organs among the invertebrate animals

What’s Annelida (segmented worms)?

•  Protostome eucoelomates

• Clade Lophotrochozoa

• Body plan

  • Segmented

  • Each segment is separated form the other by a thin layer of tissue

  • Each segment acts as its own small body cavity

● Advantageous cause if one segment is affected no other segment is affected

• Ventral nerve chord and dorsal heart

• Full digestive tract and muscle around digestive tract

• Many species have trochophore larva

What’s Polychaete worms ?

• A type of annelidia, that is paired parapodia with numerous setae

  • ●  Segmented

  • ●  Each segment carries a pair of parapodia which is used in locomotion and gas exchange

  • ●  parapodia have hair like projections called setae

What’s Oligochaete worms?

– A type of annelidia, e.g. earthworms (no parapodia, but often have setae)

What’s Hirudinea?

• leeches

  • ●  Anticoagulant - hirudin

  • ●  Not segmented on the inside, don’t have that tissue

  • ●  Lack setae

  • ●  Mouth is suction disc

  • ●  Predators survive on blood from host

  • ●  Some are specific to certain hosts and some don’t care

What does it mean to be into optimal range?

(temperature, oxygen) → to achieve homeostasis

What are Physical and chemical features of the environment?

• ○  Temperature

• ○  Oxygen availability

• ○  Water (and salt) availability

• ○  Cellular homeostasis

■ Biochemical reactions of life optimized to a relatively narrow range of conditions

What’s difference between Regulators vs conformers?

In order to achieve the basic life functions, there’s a relatively narrow range of conditions that need to be met

• Conformers → animal match their

  environment, environment changes they

  change

• Regulators → maintain constant internal

  condition even with changing external

  environment

• In reality

● You get like a mixture of regulation and conforming

○ You don’t get perfect conformers/regulators

• Regulators have a higher metabolic cost because they have to maintain the internal environment as the external environment changes (they need energy)

  • Can deal with a wider range of environmental condition

  • Fluctuating environments → regulating is ideal

• Animal sin a stable environment → conforming is ideal cause it is a

low cost energy, and stable environment = stable internal in their energetic cost

• Differ

• Metabolic rate = rate of energy consumption

■ Within the processes that go on during metabolism, a lot of heat production occurs, so we can measure an animal’s metabolic rate by measuring heat production → basic costs to run the animal

● Ideally measured when

• Animal not active

• Animal not growing/reproducing