Practical 2

Seasonal breeders

reproductively active during only part of the year, gestation lasts several months then not pregnant during the rest of the year (oceanic whitetips and threshers)

Punctuated Breeders

often pregnant for a full year, but spend 1+ intervening years non-pregnant (tiger sharks)

Continuous Breeders

Reproductively active all year long (Gulper sharks)

Oviparity

Egg-laying, externally deposited eggs are typically in leathery/durable shells

Viviparity

live birth

oviviparity

eggs develop and hatch inside mother, live birth

Parthenogenesis

Clonal or "virgin” birth

Yolk-Sac

retention of fertilized eggs throughout development of embryo within the uterus, no other maternal input is supplied, widespread among elasmobranchs

Histrotrophy

Initial nutrition by yolk-sac, tehn by “uterine milk” or histrotroph, can be limited “mucoid” or lipid rich

Placental

Most advanced form of nutrition

Oophagy

“egg eating”, initial nutrition by yolk-sac then embryos feeed on unfertilized eggs

Adelphophagy/Embryonic Cannibalism

Embryos ingest other embryos and unfertilized eggs

Lecithotrophy

entire duration of embryonic development is supported by yolk’

Matrotrophy

At least part of fetal development is supplemented by maternal input of nutrients during fetal development

Chemoreception

physiological response to chemical stimuli, taste and smell

Mechanoreception

Physiological response to changes in pressure, Touch and vibrations

Vision

Physiological response to changes in light stimuli, Not all species see same spectrum of light

Electroreception

physiological response to electric currents

Tripartite brains

Prosencephalon, Mesencephalon, Rhombencephalon

Prosencephalon

Forebrain, includes Telencephalon and Diencephalon

Mesencephalon

Midbrain, includes Optic lobes

Rhombencephalon

Hindbrain, includes Metencephalon and Myelencephalon

Spinal cord

Part of nervous system contained in the spinal column

Cerebrum

Principal and most anterior part of the brain in vertebrates, consists of a left and right hemisphere, separated by a fissure. responsible for integration of complex sensory and neural functions and initiation and coordination of voluntary activity in the body

Cerebellum

Part of the brain at the back of the skull in vertebrates, coordinates and regulates muscular activity

Olfactory sacs

Function in olfaction

Cranial nerves

come directly from the brain (different from spinal nerves)

Meninges

Membrane surrounding brain, containing cerebrospinal fluid

Middle Devonian

Tetrapods diverged from Sarcoptergian ancestors during the _________

Carnivorous Adults, Thin and permeable skin, ectothermic, eggs covered with jelly capsule, three-chambered heart

Amphibian defining characteristics

Frogs

Family Ranidae

Urodela or Caudata

Salamanders

Salamanders

Simple tetrapod body plan

do not have independent movement of limbs (movement like fish/eels-sine wave)

Gymnopiona

Caecilians

Caecilians

Worm-like (annuli)

Fossorial

Different skull types within

Anura

Toads and Frogs

Toads and Frogs

Increased specialization of bones and muscles,

Not all are leapers

Fossorial

burrow in the ground

Annuli

Worm-like

Leapers

have elongated hind limbs for jumping

Toads

Family Bufonidae

Bufonidae

Short, stubby bodies and hindlegs

Warty, dry skin

No cutaneous respiration

Paratoid (poison) glands behind the eyes

Lays eggs in line

Ranidae

Strong, long webbed hind feet

Mucus-covered smooth skin

Lays eggs in clusters

Nictating membrane

“third eyelid”

Aids in protection and moisture retention

Tympanic Membrane

“eardrum

Different sizes based on needing to hear different frequencies

Manus

4 digits on front appendage

Pes

5 digits on rear appendage

Amphibian reproduction

Diverse modes of reproduction

Almost all must return to water to breed

External fertilization

Amplexus

Foam nests

Internal Fertilization

Sperm packets

Phallodeum

Single palate

Anuran oral cavity and pharynx

Limb Formation, Multiple fusions of bones

Anuran Skeletal Anatomy

Lungs, Bladder, and Fat bodies

Anuran visceral anatomy

3-chambered heart

Anuran Cardiovascular anatomy

Left atrium, right atrium, ventricle

3-chambered heart

Lungs, skin, mouth lining

respiration surfaces

Upper Carboniferous

Amniotes arose in ________, major radiation in Permian

amniote

refers to amniotic egg

Amniotic egg

Internal fertilization

No metamorphosis stage

Skin (prevent desiccation)

includes most extant tetrapods

Amniote characteristics

Chorion, Amnion, Allantois

Extraembryonic Membranes (amniotic egg)

Chorion

Outer membrane

surrounds entire contents of egg

Gas exchange and embryo protection

Amnion

Inner membrane

surrounds embryo

Additional embryo protection with amniotic fluid

Allantois

Beneath Chorion

Stores nitrogenous waste form embryo and oxygen transport

Lepidosauromorpha and Archosauromorpha

Infraclasses within Reptilia

Lepidosauriformes

Lepidosaura Superorder

Rhynchocephalia and Squamata

Lepidosauriformes orders

Lacertilia, Amphisbaenia, Serpentes

Squamata suborders

Crocodylomorpha

Archosauromorpha superorder

Crocodilia

Crocodylomorpha order

Diapsidia

arose in upper carboniferous period

name means “two arches” (upper and lower temporal arches & 2 temporal fenestrae)

Contains Lepidosauromorphs and Archosauromorphs

Testudines/Chelonii

Turtles

Turtles

arose in triassic period

secondarily anapsid skulls (no temporal fenestrae)

temp dependent sex determination during embryonic development

formed of dermal bone

carapace

plastron

fused to vertebral column

turtle shells

carapace

upper turtle shell

plastron

lower turtle shell

turtle lungs

attached to carapace and connective tissue, which is attached to viscera

Viscera

contracts for exhale and squeezes against lungs, moves away for inhale

Cryptodires and Pleurodires

Testudines suborders

Cryptodires

Retracts head into shell by bending neck into vertical S shape

Most turtles (snapping turtle, red-eared slider, tortoises)

Pleurodires

Retracts head by bending the neck horizontally

All are semi-aquatic

ex. African pond turtle

Superorder Lepidosauria

Largest extant group of non-avian reptiles

contains orders Rhynocephalia and Squamata

Predominantly terrestrial

Skin covered with scales, relatively impermeable to water

Rynchocephalia and Squamata

Lepidosauria orders

Order Rynchocephalia

Tuatara

1 Species-native to New Zealand

Forage at night when it’s cold (temperate climate)

Lowest active body temperature of any extant reptiles ( 13˚C on avg)

Retains diapsid skull condition

Order Squamata

Determinate Growth

Squamate skull condition

Greatest variation in size of any extant order of reptiles (<1 inch and >20 ft)

Suborder Amphisbaenia

Worm lizards

Worm lizards

Earliest known representatives in Late Cretaceous

Fossorial

Most are totally limbless

Body divided into annuli

Integumentary muscles allow both forward and backward movement underground

Genus Bipes

has retained forelimbs (Front limbs)

Suborder Lacertilia

Lizards

Lizards

First seen in early Triassic

Varied diets

Eyelid with nictating membrane present

Sternum present

Most are small (80% weigh less than 20g)

Suborder Serpentes

Snakes

Snakes

Descended form limbed squamates (all species are limbless)

Range in size from 10 cm to 3m

scales differntiated into shields/plates and shed all at once

Organs are often elongated (may be reduced or lost on one side)

Sternum absent

Some are venomous

Aglyph

Without fangs

Opisthoglyph

Fangs in rear of maxilla

Proteroglyph

Fangs in fixed position at front of maxilla

Solenoglyph

Fangs which rotate on maxilla

Garter Snake

Genus Thamnophis

Small-medium sized snakes in family COlubridae

Native to North and Central America

Variable in appearance, currently 35 species recognized

Varied diets from wide distribution in different habitats