5 - Amphibians Flashcards Preview

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Flashcards in 5 - Amphibians Deck (28)
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1
Q

What are amphibians

A

First terrestrial vertebrates and first tetrapods

2
Q

Amphibians double life

A

between water and land in different life stages

3
Q

tetrapods

A

Sarcopterygian descendants that possess well-formed forelimbs and hindlimbs
Crown tetrapods
Complicated phylogeny due to tons of extinctions and radiations

4
Q

Ancient tetrapod like lobe finned fish

A

Tiktaalik - 375 mya - like lobe finned fish but with stronger forelimbs

5
Q

Ancient tetrapods fossils

A
  • good fossils
  • best are from greenland
  • ichthyostega (365 mya)
  • had bone fusions to be able to prop itself up and neck vertebrae so head can move
6
Q

Ichthyostega

A
  • heavy pectoral and pelvic girdle and sturdy limbs
  • for movement across ground against gravity
  • strong jaws
  • probably shallow water predator
7
Q

Important characteristics of fossils

A
  • mobile neck for feeding
  • more rigid vertebral column for gravity
  • 4 muscular limbs with discrete digits
  • sacral vertebra for gravity (fuses vertebral column and pelvis)
  • loss of opercular bones, notochord, fin rays and some cranial bones
8
Q

Class amphibia 3 orders

A

gymnophiona
caudata
anura

9
Q

Order gymnophiona

A
  • caecilians
  • tropical burrowers feeding on soil invertebrates
  • skin folds (appear segmented)
  • internal fertilization
  • larval stages within oviducts and young emerge as miniature adults
  • others lay eggs with aquatic larvae or embryos that develop on land
10
Q

Order caudata what are they where are they

A

Salamanders
Northern hemisphere mostly
Secondary radiation to tropical/subtropical regions

11
Q

Salamanders 3 traits

A

tail throughout life
Unspecialized legs
Internal fertilization

12
Q

Terrestrial salamanders

A

Live in moist forest floor littered with aquatic larvae

13
Q

Paedomorphic

A

retain many larval characteristics when they become sexually mature

14
Q

Obligate paedomorphosis

A
  • occurs in mudpuppies
  • legs and gills and completely aquatic
  • do not undergo metamorphosis
15
Q

Facultative paedomorphosis

A
  • retain larval characteristics as long as pond retains water
  • when pond dries, metamorphose into adult terrestrial form
16
Q

Plethodontidae

A
  • most fully terrestrial salamanders
  • most lay eggs on land
  • young hatch as mini-adults
17
Q

Aquatic salamanders

A
  • newts
  • most of their lives in water
  • may retain caudal fin
18
Q

Largest north american salamander

A

hellbender

- reqires fast flowing well-oxygenated water (thin skin for gas exchange with lots of folds for increased surface area)

19
Q

Order anura are what

A

frogs/toads

20
Q

Toads

A

dry, warty skin and more terrestrial sometimes

family bufonidae

21
Q

Frogs

A

smooth skin, more aquatic usually

family ranidae

22
Q

Adult/larvae toads and frogs

A

adults lack tails, caudal vertebrae fuse into urostyle
hindlimbs long, muscular and end in webbed feet
External fertilization
Eggs and larvae aquatic usually
Larvae=tadpoles with well developed tails
Larvae are herbivores, adults are not
Rapid metamorphosis

23
Q

Tree frog eggs

A

Laid on underside of leaves and tadpoles emerge and drop directly into pond below

24
Q

Parental care in anurans

A

backpack frog

25
Q

Toxins

A

Some anurans have skin toxins

  • poison arrow/dart frogs have gladular secretions in their skins that are neurotoxins. Protects them from predators. Bright colours = warning to predators
  • some secretions are antibacterial, antifungal and even anticancer
26
Q

Conservation issues

A
  • disappearing quickly
  • due to double life and thin permeable skin
  • drying up of important places due to climate change
  • fungus
  • susceptible to pollution
27
Q

SARA

A

Species at risk act in canada
list of all plant and animal species federally recognized as special concern, threatened, endangered, extirpated and extinct in canada (19 amphibians on the list)

28
Q

Great lakes population of tiger salamanders

A

extirpated