reptiles amphibians
Download
Skip this Video
Download Presentation
REPTILES & AMPHIBIANS

Loading in 2 Seconds...

play fullscreen
1 / 73

REPTILES & AMPHIBIANS - PowerPoint PPT Presentation


  • 341 Views
  • Uploaded on

REPTILES & AMPHIBIANS. The Rise of Amphibians (Devonian Period) A. Amphibians have a body plan and mode reproduction somewhere between “fishes” and “reptiles.” They are vertebrates with a bony endoskeleton and a four-legged aquatic ancestor. REPTILES & AMPHIBIANS.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'REPTILES & AMPHIBIANS' - Philip


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
reptiles amphibians
REPTILES & AMPHIBIANS
  • The Rise of Amphibians (Devonian Period)

A. Amphibians have a body plan and mode reproduction somewhere between

“fishes” and “reptiles.”

They are vertebrates with a bony

endoskeleton and a four-legged aquatic

ancestor.

reptiles amphibians2
REPTILES & AMPHIBIANS

The 4 classes of terrestrial (tetrapods) vertebrates:

  • Amphibians
  • Reptiles
  • Birds
  • Mammals
reptiles amphibians3
REPTILES & AMPHIBIANS
  • Scientific classification

Kingdom: AnimaliaPhylum: ChordataSubphylum: VertebrataClass: Amphibia

reptiles amphibians4
REPTILES & AMPHIBIANS
  • Subclasses and Orders of Amphibians
  • Order Temnospondyli- extinctSubclass Lepospondyli- extinctSubclass Lissamphibia Orders

AnuraCaudataGymnophiona

reptiles amphibians5
REPTILES & AMPHIBIANS

1. Life on land presented new challenges to the emerging amphibians.

The idea here is that asteroids that hit

earth caused the mass extinction of

marine life and affected much of the

available O2 at the sea’s surface. Since

the tetrapods had lungs they could take

advantage of gulping air while spending

some of their time on land.

reptiles amphibians6
REPTILES & AMPHIBIANS

Scientists say no significant genetic

change would be required to make the

transaction from lobed fins to limbs.

They contend that even a single

mutation in one of the so-called,

“master genes” could lead to a big

change in morphology.

reptiles amphibians7
REPTILES & AMPHIBIANS

a. Water availability was not reliable.

b. Air temperatures were variable, and air itself was not the strong supporting medium that water was, but it was a richer source of oxygen. Lungs had to be modified in ways that enhanced O2 uptake. Circulatory systems became more efficient in rapidly

moving oxygen to cells.

reptiles amphibians8
REPTILES & AMPHIBIANS

Both of these modifications increase

the capacity for aerobic respiration,

thus generating more ATP for use in

increased activity.

c. New habitats, including vast arrays of

plants, insects, necessitated keener

sensory (vision, hearing, balance) input.

As a result, different regions of the brain

further developed.

reptiles amphibians9
REPTILES & AMPHIBIANS

d. Fortunately, climate shifts in the

Carboniferous provided an abundance

of insects as food for the amphibians.

reptiles amphibians10
REPTILES & AMPHIBIANS
  • Amphibians developed with the characteristics of pharyngeal slits/gills, a dorsal nerve cord, a notochord, and a post-anal tail at different stages of their life. Though early tetrapods (which appeared 390 million years ago in the Devonian period) are often referred to as "amphibians", the first true amphibians appeared during the early Carboniferous period.
reptiles amphibians11
REPTILES & AMPHIBIANS
  • Superorder Salientia
  • Triadobatrachus (Triassic)
  • Order Anura (frogs and toads) Jurassic to recent - 5,296 recent species
  • Order Caudata or Urodela (salamanders): Jurassic to recent - 555 recent species
  • Order Apoda (caecilians): Jurassic to recent - 171 recent species
reptiles amphibians12
REPTILES & AMPHIBIANS

2. Existing amphibians share several

common characteristics:

a. All have bony endoskeletons and

usually four legs.

b. Most shed their eggs into water,

which is also home to a free-

swimming larval stage.

reptiles amphibians13
REPTILES & AMPHIBIANS

c. Depending on their habitat,

amphibians can respire by use of

gills, lungs, skin, and pharyngeal

lining.

d. The skin is usually thin and some-

times supplied with glands that

produce toxins. We’ll see this

shortly.

reptiles amphibians14
REPTILES & AMPHIBIANS

The word ‘amphibian’ comes from the Greek meaning, “both” (amphi), and bios, meaning, “life”.

It describes cold-blooded animals with backbones that spend their lives both in fresh water and on land.

reptiles amphibians15
REPTILES & AMPHIBIANS

When we say, ‘cold-blooded’ we mean that the amphibians do not hold or regulate their own body temperature.

Their internal body temperature depends on the external environment. They must absorb the warmth of the sun or become sluggish at very cold temperature to maintain bodily heat.

reptiles amphibians16
REPTILES & AMPHIBIANS

The Class Amphibia contains three orders:

  • Anura (frogs and toads)
  • Urodela (salamanders and newts)
  • Apoda (caecilians)
reptiles amphibians17
REPTILES & AMPHIBIANS

FROG TOAD SALAMANDER

reptiles amphibians18
REPTILES & AMPHIBIANS

NEWTS CAECILIANS

reptiles amphibians19
REPTILES & AMPHIBIANS

Most amphibians share 5 key characteristics:

1. Legs – adapted to living on land (frogs, toads, salamanders, newts all have 4 legs)

2. Lungs – larval amphibians have gills, most

adult amphibians breathe with a pair of lungs (salamanders are an exception)

reptiles amphibians20
REPTILES & AMPHIBIANS

3. Double-loop circulation – two large veins called Pulmonary veins return oxygen-rich blood from the lungs to the heart. Oxygen-rich blood is then pumped to the tissues.

4. Partially divided heart – the atrium of the heart is divided into left and right sides, but the ventricle is not. A mixture of oxygen- rich and oxygen-poor blood is delivered to the tissues.

reptiles amphibians21
REPTILES & AMPHIBIANS

5. Cutaneous respiration - besides breathing with their lungs, amphibians take up oxygen through their skin.

reptiles amphibians22
REPTILES & AMPHIBIANS

Double-loop circulation in amphibians:

reptiles amphibians23
REPTILES & AMPHIBIANS
  • Life Cycle ‘Metamorphosis” of a Frog (pg. 758-759)
reptiles amphibians24
REPTILES & AMPHIBIANS
  • Frogs and Toads (4,000 species)

1. These animals are distinctive with

their long hindlimbs capable of res-

ponding to powerful muscles, which

allow them to leap into the air.

2. Their success on land is due in part

to: the excellent prey-grasping

capability of the tongue attached to the

front of the mouth.

reptiles amphibians25
REPTILES & AMPHIBIANS

3. Frog skin has mucous glands, poison

glands & antibiotics that provide

protection against pathogens in an

aquatic habitat.

4. Scientists have noticed frog populations

on the decline due to increases in

parasitic attacks, predation, UV

radiation, habitat losses & chemical

pollution.

reptiles amphibians26
REPTILES & AMPHIBIANS

Frog versus Toad

  • Frog has two bulging eyes
  • strong, long, webbed hind feet that are adapted for leaping and swimming
  • smooth or slimy skin (generally, frogs tend to like moister environments)
  • Frogs tend to lay eggs in clusters.
reptiles amphibians27
REPTILES & AMPHIBIANS

Frogs versus Toads

  • Toads have stubby bodies with short hind legs (for walking instead of hopping)
  • warty and dry skin (usually preferring dryer climates)
  • paratoid (or poison) glands behind the eyes
  • The chest cartilage of toads is different.
  • Toads tend to lay eggs in long chains.
reptiles amphibians28
REPTILES & AMPHIBIANS
  • Salamanders

1. Live in temperate zones & in tropical

areas of Central and South America

numbering about 380 species

2. When they walk, the body bends from

side to side, much like a fish moving

through water.

reptiles amphibians29
REPTILES & AMPHIBIANS

3. Adults may retain larval features including

gills and tail.

4. Some larvae may become sexually mature

but not reach a true adult stage

5. Both forms, larval & adult, are carnivorous.

reptiles amphibians30
REPTILES & AMPHIBIANS
  • Caecilians

1. As amphibians evolved they lost their limbs & vision, but not their prey-capturing jaws.

2. These unusual creatures live burrowed

in the forest floor where they hunt for

invertebrate prey.

3. Most of the 160 species burrow through the soil,

using touch & smell to pursue insects & earthworms. The few aquatic types use electrical cues.

reptiles amphibians31
REPTILES & AMPHIBIANS
  • Summary of amphibians:
    • They are vertebrates
    • they have bony endoskeleton
    • They have four legs
    • Their body plan and mode of reproduction is somewhere between “fishes” and “reptiles”
reptiles amphibians32
REPTILES & AMPHIBIANS

- Their transition to land involved:

development of legs

more efficient lungs

more efficient heart

reptiles amphibians33
REPTILES & AMPHIBIANS

Because of this transition from water to land:

  • Amphibians had to contend with a drier habitat. This required a modified way to enhance oxygen uptake through their lungs
  • This drier habitat required that they go back to a water environment for laying of eggs
reptiles amphibians34
REPTILES & AMPHIBIANS
  • Legs, sufficient to support their body weight, allowed them to move from land to water when necessary.
  • Their circulatory systems became more efficient to provide oxygen to all cells which, over time, increased the capacity for aerobic respiration and subsequently greater production of ATP – allowing for more activities.
reptiles amphibians35
REPTILES & AMPHIBIANS
  • Scientific Classification of Reptiles

Kingdom: AnimaliaPhylum: ChordataSubphylum: VertebrataClass: Sauropsida

reptiles amphibians36
REPTILES & AMPHIBIANS
  • REPTILES
  • Reptiles are tetrapods and amniotes, animals whose embryos are surrounded by an amniotic membrane. Today they are represented by four surviving orders:
  • Crocodilia (crocodiles, caimans and alligators): 23 species
  • Rhynchocephalia (tuataras from New Zealand): 2 species
  • Squamata (lizards, snakes and amphisbaenids ("worm-lizards")): approximately 7,600 species
  • Testudines (turtles): approximately 300 species
reptiles amphibians37
REPTILES & AMPHIBIANS

Reptiles are found on every continent except for Antarctica, although their main distribution comprises the tropics and subtropics. Though all cellular metabolism produces some heat, modern species of reptiles do not generate enough to maintain a constant body temperature and are thus referred to as "cold-blooded" (ectothermic).

reptiles amphibians38
REPTILES & AMPHIBIANS

Sea Turtle for an exception: a reptile that elevates its body temperature well above that of its surroundings. Normally they rely on gathering and losing heat from the environment to regulate their internal temperature, e.g, by moving between sun and shade, or by preferential circulation — moving warmed blood into the body core, while pushing cool blood to the periphery

reptiles amphibians39
REPTILES & AMPHIBIANS

Reptiles evolved from tailed amphibian ancestors. There are nearly 8000 species that are divided into four orders; snakes and lizards, crocodiles and alligators, tortoises and turtles, and tuataras.

  • A reptile has the following features;

cold blooded

dry, scaly skin

tough shell on eggs

eggs are laid on land

reptiles amphibians40
REPTILES & AMPHIBIANS
  • The Rise of Amniotes - Reptiles

During the late Carboniferous, amphibians

gave rise to the amniotes (birds, reptiles, mammals).

A. Four features were critical to amniotes’

escape from water dependency:

1. They produce amniote eggs with internal

covering membranes and a shell, which allow

the eggs to survive in dry habitats.

reptiles amphibians41
REPTILES & AMPHIBIANS
  • Amniote egg contains a membraneous sac that surrounds and protects the embryo.
reptiles amphibians42
REPTILES & AMPHIBIANS
  • Allantois

The word comes from the Greek word for sausage, which the allantois resembles. This sac-like structure is primarily involved in respiration and excretion, and is webbed with blood vessels. It is primarily found in the blastocyst stage of early embryological development, and its purpose is to collect liquid waste from the embryo.

reptiles amphibians43
REPTILES & AMPHIBIANS
  • The structure first evolved in reptiles and birds as a reservoir for nitrogenous waste, but also as a means for oxygenation of the embryo. Oxygen is absorbed by the allantois through the egg shell . The allantois functions similarly in monotremes, which are egg-laying mammals.
reptiles amphibians44
REPTILES & AMPHIBIANS
  • In most marsupials, the allantois is avascular, having no blood vessels, but still serves the purpose of storing nitrogenous waste. Also, most marsupial allantoises do not fuse with the chorion.
  • In placental mammals, the allantois is the precursor of the mature umbilical cord
reptiles amphibians45
REPTILES & AMPHIBIANS

2. First vertebrates to form eggs with

internal membranes that conserve

H2O and cushion an embryo, and

metabolically support it.

3. Amniotes have a toughened, dry or

scaly skin that is resistant to drying.

reptiles amphibians46
REPTILES & AMPHIBIANS

4. They have a copulatory organ that

permits internal fertilization.

5. Their kidneys are good at conserving

water.

Again, these amniotes (mammals, turtles, lizards, snakes, crocodiles & birds) are the only tetrapods that can reproduce successfully away from aquatic habitats, while having the embryos develop to advanced stage before hatching or being born in a dry habitat.

reptiles amphibians47
REPTILES & AMPHIBIANS
  • “Reptiles” demonstrate certain advantageous features compared to amphibians.

1. Modification of limb bones, teeth, and

jaw bones allowed greater exploitation

of the insect life emerging in the Late

Carboniferous.

2. Development of the cerebral cortex permitted

greater integration of sensory input and motor

response.

reptiles amphibians48
REPTILES & AMPHIBIANS

3. A four-chambered heart fully separated

into two halves and more efficient lungs

allowed greater activity. Crocodilians

were the first to exhibit this feature.

Though the reptiles’ brain is small

compared to it’s body mass, behavior

governed by it is advanced to that seen

in Amphibians.

4. Descendants of the surviving dinosaurs

became the lineage of reptiles.

reptiles amphibians49
REPTILES & AMPHIBIANS

5. Transdermal gas exchange seen in

amphibians is abandoned by

reptiles because of their well develop-

ed lungs.

reptiles amphibians50
REPTILES & AMPHIBIANS
  • Circulatory systems

Fish Amphibian Reptile, Bird

Mammal

reptiles amphibians51
REPTILES & AMPHIBIANS

Humans, birds, and mammals have a 4-chambered heart that completely separates oxygen-rich and oxygen-depleted blood. Fish have a 2-chambered heart in which a single-loop circulatory pattern takes blood from the heart to the gills and then to the body. Amphibians have a 3-chambered heart with two atria and one ventricle.

reptiles amphibians52
REPTILES & AMPHIBIANS

A loop from the heart goes to the pulmonary capillary beds, where gas exchange occurs. Blood then returns to the heart. Blood exiting the ventricle is diverted, some to the pulmonary circuit, some to systemic circuit. The disadvantage of the three-chambered heart is the mixing of oxygenated and deoxygenated blood. Reptiles, all birds and mammals, have a 4-chambered heart, with complete separation of both systemic and pulmonary circuits.

reptiles amphibians53
REPTILES & AMPHIBIANS
  • A Sampling of Existing Reptiles – (Latin, to creep)

Reptiles are a diverse group. They are considered an animal because they have basic amniote traits but not those of mammals or birds.

A. Turtles

1. The distinctive shell offers protection while

conserving water and body heat.

reptiles amphibians54
REPTILES & AMPHIBIANS

2. The shell is connected to the skeleton. Their teeth are tough, horny plates designed for gripping & chewing

food.

3. Turtles lay their eggs on land, where

predation is high.

reptiles amphibians55
REPTILES & AMPHIBIANS
  • Anatomy of a Box Turtle
reptiles amphibians56
REPTILES & AMPHIBIANS
  • Turtle shell structure
reptiles amphibians57
REPTILES & AMPHIBIANS
  • Turtle eggs and newborn
reptiles amphibians58
REPTILES & AMPHIBIANS
  • Lizards

1. Most lizards are small-bodied insect

eaters; their most usual habitats are deserts

and tropical forests.

2. Lizards are also prey for many other animals,

but are quick in movement and have the

unique ability to sever their own tails if it is

grabbed by a predator.

reptiles amphibians60
REPTILES & AMPHIBIANS
  • Scientific classification

Kingdom: AnimaliaPhylum: ChordataClass: SauropsidaOrder: SquamataSuborder: Lacertilia

reptiles amphibians61
REPTILES & AMPHIBIANS
  • Snakes

1. Snakes are limbless but retain vestiges

of hind limbs; they are excellent

predators.

2. Snakes have the ability to swallow prey

larger than they are due to flexible skull

and jaw bones.

3. All snakes are carnivores. Some suffocate their

prey, and some kill their prey with venom.

reptiles amphibians62
REPTILES & AMPHIBIANS

95% of all living reptiles are composed of Lizards and Snakes.

reptiles amphibians63
REPTILES & AMPHIBIANS
  • Tuataras

1. Although they resemble lizards, they

are evolutionarily more ancient. They

resemble amphibians with the brain

and the way they walk.

2. They do not engage in sex until they

are twenty years old!.

reptiles amphibians64
REPTILES & AMPHIBIANS

3. Only two species remain today;

they live on islands off the shore of

New Zealand.

4. Like lizards, tuatarus have a 3rd eye

under the skin with a retina, a lens,

and nerves to the brain. They also

may live to be 60 years old.

reptiles amphibians65
REPTILES & AMPHIBIANS
  • Scientific Classification of Tuataras

Kingdom: AnimaliaPhylum: ChordataClass: SauropsidaOrder: SphenodontiaFamily: SphenodontidaeGenus: Sphenodon

reptiles amphibians66
REPTILES & AMPHIBIANS
  • Crocodilians

1. Crocodiles and alligators all live in or

near water.

2. They are the largest living reptiles.

3. The body plan includes a long snout;

body temperature is regulated behavior-

ally (ectothermic).

reptiles amphibians67
REPTILES & AMPHIBIANS

4. The ventricle of the heart is divided

into right and left chambers – more

like the heart of birds than that of

other reptiles.

reptiles amphibians68
REPTILES & AMPHIBIANS

4. Like other reptiles and birds, crocodilians adjust body temperature with behavioral and physiological mechanisms.

5. They are like birds in displaying complex social behaviors, such as parents guarding nests

and assisting hatchlings into water. This trait

and others suggest that crocodilians and birds

share a common ancestor.

reptiles amphibians69
REPTILES & AMPHIBIANS
  • ReptilianOrders
  • Procolophonida (extinct)
  • Araeoscelidia (extinct)
  • Avicephala (extinct)
  • Younginiformes (extinct)
  • Ichthyopterygia (extinct)
  • Placodontia (extinct)
  • Nothosauria (extinct)
reptiles amphibians70
REPTILES & AMPHIBIANS
  • Orders (cont.)
  • Plesiosauria (extinct)
  • Prolacertiformes (extinct)
  • Pterosauria (extinct)
  • Saurischia (extinct)
  • Ornithischia (extinct)
reptiles amphibians71
REPTILES & AMPHIBIANS
  • Reptilian Orders (cont.)
  • Testudines
  • Squamata
  • Sphenodontia
  • Crocodilia
reptiles amphibians72
REPTILES & AMPHIBIANS
  • Kingdom: AnimaliaPhylum: ChordataSubphylum: VertebrataClass: AmphibiaSubclasses and Orders
  • Order Temnospondyli- extinctSubclass Lepospondyli- extinctSubclass Lissamphibia Orders: AnuraCaudataApoda
reptiles amphibians73
REPTILES & AMPHIBIANS
  • Reading Assignment:
  • Pages: 338-342 Chap. 20

Pages: 444-457 Chap. 26

Pages: 758-759 Chap. 43

Appendix I : Kingdom Animalia

- tetrapods

- amniotes

ad