Unit 6: Animals Flashcards
Characteristics of the Animal Kingdom
Opisthokonta - Single posterior flagellum (sperm cells)
- all diploids
- Morphology of animal determined by developmental cues (unlike a tree, limbs all same spots)
-Complex tissue structure
Complex tissue structure
needed to find food and escape danger
Muscle tissue: movement
Neural tissue: Communication of multiple tissues
animal cells diff from plant cells bc of…
Tissue cells lack cell walls (may have a supportive matrix like bone)
Epithelial tissue: protects internal and external body surfaces
Differential tissues: carry out specific functions
group animals based on
tissues
Parazoa (P. Porifera) – Sponges:
No specialized tissues
24 cell types
Eumatezoa
(True Animals) Cnidaria, Ctenophera, Bilateria – specialized tissues derived from germ layers of the embryo
Gastrulation: Organogenesis
programmed development of tissue types and organ systems
Role of Hox genes in development
“Master control genes” – turn on or off large #s of genes
- controls general body plan
* Verts 4 sets, Inverts 1 set
Part of body plan: Symmetry
Ability to divide an animal in equal halves on at least one plane
Asymmetrical animals
Parazoa and Placozoa
Radial Symmetry
Divisible on two planes, or arranged around a central axis
-Cnidarians, Ctenophorans
Bilateral symmetry
division along the middle plane
- Head and tail, right and left, front and back
–Bilateria
what organisms are bilaterally symmetrical
All Eumetozoa (except those mentioned earlier…)
Echinodermata have bilateral symmetry in larval stage, are classified in
Bilateria
diploblast vs triploblast
Diploblasts: 2 layers –*Endoderm, ectoderm
Triploblasts (bilateria): 3 layers *Endoderm, ectoderm, mesoderm
3 layer descriptions
- endo, ecto, meso
Endoderm: lining digestive tract (and organs), trachea, bronchi, lungs
Ectoderm: Epithelial covering of body, nervous system
Mesoderm: specialized muscle tissues, connective tissue, blood cells
Triploblasts further divided by…
coelom type
Coelom
internal fluid-filled cavity surrounded by mesoderm,b etween visceral organs and body wall
Acoelomates
mesoderm completely filled with tissue – Platyhelminthes
Pseudocoelomates
Cavity lined with both mesoderm & Endoderm (only partially mesoderm) – Nematodes
true coelomates
Eucoelomates : Annelids, Mollusks, Arthropods, Echinoderms, Chordates
- is completely surrounded by muscle
Protostome vs Deuterostome
Protostome (mouth first): Mouth from Blastopore (Mollusk, Annelid, Arthropods)
Deuterostome (Mouth second): mouth from other end of tube – anus from blastopore (Chordates and Echinoderms) … we form anus first
Differences in Protosome Development: Schizocoely, Spiral Cleavage, Determinate Cleavage:
Schizocoely: 2 clumps form cavities then merge
Spiral Cleavage: cells rotated along poles – misaligned
Determinate Cleavage: Embryonic cell type determined at division
Deuterostome Development: Enterocoely, Radial Cleavage, Indeterminate Cleavage
Enterocoely: mesoderm block pinches to form cavity
Radial Cleavage: parallel alignment of cells between poles
Indeterminate Cleavage: Embryonic cells not committed to specific cell types
–> Importance of Stem Cells in research
how many phyla in animal kingdom
35-40 Phyla (only one subphyla has backbone)
choanoflagellate (protozoan) similar to
Choanocytes of porifera
within Eumetozoa
Bilateria and Radiata
within Bilateria
Protostomes and Deuterostomes
within Protostomes: Lophotrochozoa, Ecdysozoa
Lophotrochozoa: Trochophore larva or Lophophore (feeding structure)
Ecdysozoa: (moulting exoskeleton) Nematodes & Arthropods
- ask yourself if it moults or not
Nuclear and Ribosomal DNA
- enhances our understanding of relationships
Pre-Cambrian Animal Life
- Edicarans: featherlike
- Sponge-like (Coronacollina acula)
Cambrian Explosion: Why? (at this time and not another)
- Environmental changes = suitable for animal life (oxygen-rich etc)
- Hox Genes
- Predator/prey relationships and co-evolution (bc selection pressure etc)
Cambrian Explosion: 542-488 MYA – Animals resembling (we saw)…
-pred/prey evol arms race
- Top predator = Arthropod
- Trilobite: most dominant species
Cambrian Explosion: Issues
likely diverse animal life existed earlier, we don’t know about because not on fossil record (ex. soft tissue)
Ordivician
- See evolution of Land Plants and Land Animals at same time
- Limbed appendages + scales to move to land
Mass Extinctions- Post Cambrian: End of Paleozoic Era, K-T Extinction, Late Cenozoic
End of Paleozoic Era – Permian reptiles replaced with Dinosaurs
K-T Extinction: Plants and dinosaurs replaced with mammals
Late Cenozoic: Ice ages, promoted speciation
Invertebrates account for
97% of all animals
Simplest Invertebrates
Sponges (P. Porifera)
Sponge Morphology: water entry and exit
- Water enters through Ostia, exits through osculum
Sponge Morphology: Mesohyl, Amoebocytes, Sclerocytes
– jelly-like wall that contains…
Amoebocytes: stem cells–deliver nutrients, produce eggs
Sclerocytes: form skeletal like support - spicules (used to identify sponges)
Sponge Morphology: Feeding chambers - Choanocytes
Choanocytes: collar cells with flagella
* Can differentiate into sperm
Sponge Morphology: cotains a spongocoel
Irregular cylinder/central cavity
Sponge Morphology: Classification (they can be…)
simple or complex with many chambers
Sponge Phylogenetics: Based on spicules 4 classes
*just read over
- Calcarea – CaCO3 spicules
- Hexactinellida (Glass Sponges)– Silicon – glass like spicules
- Demospongia – spongin - may not have spicules
- Sclerospongiae – multilayered CaCO3 skeletons
Sponge Digestion
- Food trapped by choanocytes, phagocytosis (pull it in)
Sponge Reproduction: Sexual, eggs and sperm
Monecious
* Eggs from amoebocytes, sperm from choanocytes
Sponge Reproduction: Asexual
- Budding, Fragmentation, Gemmules
Budding: genetically identical outgrowth detaches ( a lot like a plant)
Fragmentation: piece brakes off, settles on new substrate
Gemmules: only freshwater sponges, go into dormancy and then become active again
.
Cnidarian defining cell type
Cnidocyte (stinging cell)
cnidocile
hair like trigger
* Thread and barb
CNIDERIAN 2 body plans
Medusa: mobile, bell shape,
tentacles
Polyp: sessile
CNIDERIAN 2 layers + jelly-like middle
- Endoderm, Ectoderm, Gastrovascular cavity
Endoderm: gastrodermis, Ectoderm: epidermis, Nonliving Mesoglea
Gastrovascular cavity: one opening – is both mouth and anus
species of cnidaria
10,000
CNIDERIA: 2 monophyletic clades
Anthozoa & Medusozoa
Anthozoa
– Corals, sea fans, sea whips, anemones
Medusozoa 3 classes
- Scyphozoa, Cubozoa, Hydrozoa
Scyphozoa: marine jellies mainly medusa with polyp stage
Cubozoa: box jellies– most dangerous
Hydrozoa: include freshwater jellies, polyp colony, Man’O’War
Lophophore vs Trochophore
Lophophore: feeding structure – set of tentacles surrounding mouth
Trochophore: free-swimming larva – have cilia
Cestoda
tapeworms (beef and pork)
Rotiferans
Corona (head): paired ciliated feeding structures
* Body plan – Head, trunk, foot
* Monecious and Dioecious
most dioecious
Nemertea (lophotrocozoa)
Lophotrochozoa: Molluscs and Annelids both have
trochophore larvae
Mollusca
- mantle, radula
“Muscular Foot”
- internal organs are visceral mass
***Mantle – folds over visceral mass – contains gills
* Radula – feeding organ (not present in bivalves)
Major Classes of Molluscs: Polyplacophora
– chitons
has hemocoel: open body cavity with circulation
Major Classes of Molluscs: Bivalvia
– clams, oysters, geoducks, mussels, scallops
* Marine and freshwater, 2 halves
Major Classes of Molluscs: Gastropoda
- means, torsion
“stomach foot” – 1⁄2 of all molluscs
- Torsion – development – rotation around axis – allows head to be retracted
Major Classes of Molluscs: Cephalopoda
- means, examples, chromatophores, Iridophores & leucophores
“head foot” – Octopus, Squid
Chromatophores – pigment cells (yellow, red, brown, black)
*Iridophores & leucophores – reflect light
.
Metamerism
– true segmentation
* Internal and external morphological features repeated in each segment, ANNELIDS!
Clitellum
generates mucus to aid in sperm transfer, annelids!
Annelids: Polychaeta
“bristle worms”
Annelids: Oligochaeta
“few bristles”, earthworms
ANNELIDS: Hirudinea
(subclass of Oligochaeta
- Leaches
Nematodes
- Triploblast, Bilateral symmetry, pseudocoelom, molt exoskeleton
- can be Parasitic and free-living * likely the most numerous group on Earth (28000 described, 16000 are parasitic)
- Reproduction – can be Monecious, dioecious, or parthenogenic
Tardigrada
- “water bears” – 1,000 sp
- can go through cryptobiosis – protection from extremes
- Can lose 99% of body H2O and still survive
- Feed on plants, algae, small animals
- Dorsal brain and ventral nerve cord
- mostly Dioecious
Ecdysozoans: 3 groups
Nematodes and Tardigrades, Arthropods
ECDYSOZOA: Arthropoda
“Jointed Feet”, 85% of described species
Arthropoda: Ecdysis
shedding of cuticle
Arthropoda: Five subphyla
- Trilobita – all extinct
- Chelicerata
- Myriopoda
- Crustacea
- Hexapoda
Tagmosis
fusion of segments
tagmatization
organization of segments into specific regions having similar structure, function and appendages
Arthropoda subphyla: Chelicerata
– 77,000 sp
* Horseshoe crabs, scorpions, spiders, mites, ticks
* Body in two segments Prosoma & Opisthosoma
* Chelicerae – modified first appendages – claw-like or fang-like
* Pedipalps – second appendages – sense environment, manipulate food * Hemolymph has hemocyanin (Cu in place of Fe)
* Dioecious
things that can make us sick or kill us!!
Arthropoda subphyla: Myriapoda
– 16,000 sp
* Legs from 10-750
* Millipedes – 2 pairs of legs per segment
* Centipedes – 1 pair per segment
Arthropoda subphyla: Crustacea
– 70,000 sp.
* Krill, shrimp, lobster, crab, crayfish, pill bugs, barnacles
* 2 pairs antennae, mandibles as mouthparts, biramous appendages
* Cephalothorax and abdomen
* Brain, compound eyes
Arthropoda subphyla: Hexapoda
– six legs
* Head, thorax, abdomen
* Head: Upper labrum and mandibles, Sensory antennae, Compound eyes and ocelli (simple eyes)
- Abdomen: Typically 11 segments, reproductive organs
- Thorax: Wings (when present), De novo (new) adaptations – not like bat wings
- Holometabolous and Hemimetabolous reproduction
- Eusocial societies – Bees, Wasps, Ants, Termites
Echinodermata
7,000 sp – sea stars, urchins, cucumbers, sand dollars
Classes of Echinoderms: Asteroidea
(Sea Stars) – 1,800 sp, 2 stomachs, carnivores(tube feet)
Classes of Echinoderms: Ophiuroidea
(Brittle Stars)
Classes of Echinoderms: Echinoidea
(Sea Urchins and Sand Dollars) – Aristotle’s lantern (feeding)
Classes of Echinoderms: Crinoidea
(sea lilies & feather stars) – sessile, 600 sp.
Classes of Echinoderms: Holothuroidea
(Sea cucumbers) – bilateral symmetry
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Placozoa
parasites resembling amoeba, only 4 cell types
Cnidaria
Jellyfish, Corals…
Ctenophora
Comb Jellies
.
Cleavage
cell division with no cell growth
Blastula
ball of cells (hallow in inverts, little yolk)
Gastrulation
formation of primitive gut, and germ layers
Metamorphosis
complete (holometabolous) and incomplete (hemimetabolous)
