Lecture 16- Australian invertebrates' diversity Flashcards

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1
Q

What are the 6 terrestrial invertebrate phyla?

A
  1. Platyhelminthes: flatworms 2.Nematoda: roundworms 3.Annelida: segmented worms 4.Arthropoda: insects etc 5.Onychophora: velvet worms 6.Mollusca: snails etc -invertebrates are the most species rich part of the animal kingdom, and most abundant -possibly 90% of world species
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2
Q

What do Platyhelminthes look like?

A
  • bilateral symmetry
  • eye spots (light sensory)
  • dorso ventrally flattened in transverse section
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3
Q

What are the two main types of Platyhelminthes?

A
  1. Free living: e.g. brown striped flatworm, some flatworms are brightly coloured, most quite small constrained to small size 2. Parasitic: e.g. tapeworm from vertebrate digestive tract, often quite well develop interaction, some have complex life cycles, even more hosts
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4
Q

What do Nematoda look like and what are their characteristics?

A

-large groups -(roundworms):

some free-living, mostly parasitic

  • e.g. in kangaroo gut, non harmful to the animal
  • extremely sophisticated!
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5
Q

What do annelida look like and what are their characteristics?

A
  • segmented worms, like earthworms for example
  • metamorphic segmentation, both on the inside and outside
  • more complex body structure
  • some grow very big:Giant Gippsland Earthworm up to 3m long!!!
  • leeches: parasitic -also many in marine environment -e.g. rainforest groups: turquoise earthworm
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6
Q

What are the key unifying characteristics of arthropoda?

A

-largest invertebrate group in terrestrial systems 1. exoskeleton (external) & 2. jointed legs -

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7
Q

What are the characteristics of subphylum of Arthropoda the Chelicerate?

A

-(no antennae): spiders, mites, ticks & scorpions -very abundant group, 39000 species of spiders in Australia alone

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8
Q

What are the characteristics of spiders?

A

-many are active hunters and have venom to subdue or kill their prey, have fangs (inject the venom) -or have webs - some sp. exhibit maternal care: female carrying her young (e.g Wolf spider)

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9
Q

What are the characteristics of scorpions?

A

-some are active hunters, some wait and then attack -in the arid zone -sting in their tail -also in rainforests

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10
Q

What are the characteristics of subphylum of Arthropoda the Crustacea?

A

-2 pair antennae branched legs e.g. crabs, slater (pill bug) etc -most are marine

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11
Q

What are the characteristics of subphylum of Arthropoda the Myriapoda?

A

-1 pair antennae centipedes, millipedes -myriapods= many legs

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12
Q

What are the characteristics of subphylum of Arthropoda the Hexapoda?

A

-insects: butterflies, moths, ants, beetles etc. amazing diversity in morphology & ecology -good for experiments, as cheap, can manipulate, can have many in an experiment

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13
Q

What is the value of invertebrate models in connection to climate and species distribution?

A

-Common Brown Butterfly -distribution: correlates with winter rainfalls and milder temperature -

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14
Q

What is the life cycle of Common Brown Butterfly?

A

-tiny larvae and eggs probably most susceptible to dryness and heat -project to test this -and yes highly susceptible to desiccation and heat, so can’t adapt quickly

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15
Q

How was the experiment with butterflies done?

A

• Portable weather- station: macroclimate data (air temp, rainfall, wind-speed etc.) Air temp • measured Computer programs: reconstruct microclimate from macroclimate data • Data-loggers: temp & humidity in grass tussocks (sun/shade) -this was to confirm the lab results, and yes!

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16
Q

What are characteristics of the Phylum Onychophora?

A

-(velvet worms) early lineage links to arthropods -closer related to arthropods than to worms

17
Q

What are characteristics of the Phylum Mollusca?

A

-huge group in marine environments -snails etc.

18
Q

What are the fossils of invertebrates found in SA?

A

-Invertebrate fossils in SA: 600MY -also Jurassic dragonfly (approx 190MY) -have quite a few fossils in Australia -dragonflies still have the same body plan

19
Q

What are the origins of Australia invertebrate faun?

A
  1. Gondwanan groups e.g. freshwater worms 2. Asian elements e.g. bird eating spiders 3. Archaic element: descendants of widespread Pangean (when world was Pangea) groups, primitive cockroaches, scorpion flies, velvet worms
20
Q

What are some more characteristics of Onychophora (velvet worms)?

A

-up until DNA studies not many species 70 worldwide, with DNA testing 40 more genera and only in Australia have 40 species -all of them have similar body plan, similar habitat so *Allozyme (allele codes for particular enzyme or proteins= can inform us about population relations) studies on Euperipatoides leukartii: more species including E. rowelli * Euperipatoides rowelli mtDNA & micro satellite studies: found a # of divergent groups! -habitat: woods

21
Q

What was the study with velvet worms?

A

-velvet worms live in wet environment often, rotting log -habitats are small, many geographical barriers on a small scale -have area with one species and another one with another species, the overlapping zone= should have hybrid babies with defects, -the species vary by 20% in their DNA! a lot! -Birth defects in a velvet worm due to “out-breeding depression” (this is due to 2 distinct species interbreeding) low fertility & 5% of young have birth defects, e.g. missing legs -the hybrid zones supported the DNA results

22
Q

How does reproduction work in velvet worms?

A
  • not romantic
  • male comes along, puts sperm on the body of female, there her body will break down and the sperm will get into the reproductive system of the female
  • can have up to 25 embryos in her, at different development stages, this is as she can control when the sperm starts developing
  • tested for paternity, multiple fathers!

= mate selection! maximum change for offspring success