#19 reptiles

Question 1

why are reptiles the first successful colonisers of the terrestrial environment

Answer 1

• have an amniotic egg: embryo in fluid filled sac with a shell to retain the moisture
• use internal fertilisation
• have scales covering the body to prevent water loss
• excrete urea to prevent water loss
• faeces is dry to prevent water loss

Question 2

are reptiles endothermic or ectothermic

Answer 2

they are ectothermic - they have low energy requirements

Question 3

are reptiles monophyletic or polyphyletic

what does this mean

Answer 3

reptiles are polyphyletic meaning that all types of reptiles do not share a common ancestor
meaning a group of animals that appear very similar in their characteristics, but are actually derived from multiple ancestral groups

Question 4

how many species of reptiles are there

Answer 4

over 1000 species

they are a very successful group, wide diversity

Question 5

how many orders of reptiles are there

what ones are present in Australia

Answer 5

Present in australia

crocodilia: crocodiles
testudines: turtles and tortoises (Aus. doesn’t have tortoises)
squamata: snakes and lizards

only present in NZ:
rhyncocephalia: tuatara

Question 6

what is the most diverse / has the most species of reptile in Australia

Answer 6

the squamata: snakes and lizards - over 900 species

Question 7

what are methods of reproduction for reptiles?

what are their differences?

Answer 7

Oviparity

• egg laying
• this is the ancestoral trait
• most lay eggs in a burrow

Viviparity

• laying live young
• newly evolved method by some species
• most common in colder areas (more viviparous in colder areas )

Question 8

what affects sex determination in reptiles

give examples

Answer 8

sex can be determined by temperature in reptiles 
some groups are temperature dependent 
i.e. marine pitted turtle: 
- below 30 degrees offspring is male
- above 32 degrees offspring is females 
- in-between is a mixture

crocodiles

• below 30 degrees it is females
• above 32 is males
• in-between it is a mixture

in other reptiles it can be genetically determined

Question 9

what is the issue with climate change and sex ratios

Answer 9

as temperature increases this will affect reptiles whose offspring is determined by temperature. there will become offspring of all one gender.
rising temperatures will favour one sex! i.e. in crocodiles it will be all males
can lead to species extinction

Question 10

what are the groups of lizards and their characteristics?

Answer 10

Dragons - largely endemic. lay in burrows

Geckos - Some species are parthenogenic, highly vocal

Legless lizards - vocal, have ear holes, no forelimbs

Goannas

Skinks - most diverse lizard family, many of these in Aus.

Question 11

what are the groups of snakes and their characteristics

Answer 11

Blind snakes - underground, light sensitive eye spots

Pythons - diverse in northern Aus.

file snakes - aquatic, viviparous

Tree snakes

venemous land and sea snakes - both oviparous and viviparous