Presentation on theme: "Chordata: Amphibians, Reptiles and Birds"— Presentation transcript:
1 Chordata: Amphibians, Reptiles and Birds By: Nikita Mathew, Noor Al-Alusi, Sara ShuPeriod 3
2 AmniotesAn amniote is a member of a clade of tetrapods that have an amniotic egg containing specialized membranes that protect the embryo (i.e. mammals, birds and other reptiles).Embryonic membranes distinguish amniotes from tetrapod amphibians.
6 Body Cavity Body Symmetry Has Coelom Bilateral symmetry
7 Nervous System Present Brain has medulla, cerebellum, a small cerebrum Has spinal cord and nervesTwo eyes with third eyelid/protective membrane
8 Circulatory SystemAre cold blooded (body temperature same as surrounding environment)Three chambered-heart with two atria and one ventricle
9 Digestive SystemAll amphibians use mouth, stomach, and small intestine for digestionFrogs have a long sticky tongue that is usually folded backwards in their mouth
10 Excretory System Two kidneys are the main excretory organs Filter waste that leaves the body as urineLiquid and solid wastes leave through cloaca
11 Locomotion/Musculature Frogs and salamanders are tetrapods (“four feet”)Most frogs and salamanders use strong hind legs to moveCaecilians burrow in moist soil because they are legless
12 Skeletal TypeEndoskeleton—consists of hard supporting elements (cartilage and/or bone)Has axial skeleton (skull, backbone, and ribcage) and appendicular skeleton (limbs)Skeleton provides support and enables movement
13 Sensory Structures/Features Frogs and salamanders have eyes while caecilians are nearly blindCan sense vibrations on the groundFrogs have external eardrums that sit behind the eyes
14 Reproduction: Frogs and Salamanders Sexual reproductionEggs laid and fertilized outside of mother’s body in water/moist environmentEggs lack shell so are prone to dehydration so amphibians lay them in moist environments with a jelly-like layer for protection
15 Reproduction: Caecilians Only amphibians to use internal inseminationFertilized eggs are laid outside and guarded by femaleWhen hatched, caecilians are already metamorphed
16 Gas Exchange Mostly rely on moist skin for gas exchange Breathe using positive pressureLowers roof of mouth and take in air through nostrils. Nostrils then close and roof of mouth is raised, pushing air into lungs.
17 Other featuresAmphibian means “two lives” (many live in aquatic and terrestrial environments)Have complex social behaviors, including certain vocal communication during breeding
21 Nervous SystemNervous system consists of a brain, spinal cord, and sense organs.More advanced nervous system than amphibiansReptiles have much smaller brains compared with mammalsOlfactory bulbSnake’s tongue have highly sensitive smell sensors.Alligators have sensory nodules on jaws, connect to nerve fibers responding to vibrations and small pressure changes in the water.Crocodiles have similar organs on almost every scale on their body
22 Circulatory SystemCold blooded- do not use metabolism to control body temperatureBehavioral adaptations to regulate body temperatureEctothermic-absorption of external heat as main source of body heat
23 Digestive System Present [mouth, teeth, esophagus, stomach, rectum] Snakes: loosed articulated jaws and elastic skin to swallow prey larger than itself
24 Excretory System Cold blooded Covered with scales Kidneys and ureters to get rid of liquid wastesMolt/shed their skin
25 Locomotion/Musculature Snakes use waves of lateral bending to propel themselves forwardThey also grip ground with belly scales at several points, pulling its other parts forward.Other Reptiles:-stomachs close to ground- low center of gravity forces body to work more
26 Skeletal Type endoskeleton Breast bone protects lungs and heart Turtles have a hard shell that are fused to the vertebrae and ribs; defense against predators.
27 Sensory Structures/Features Scales that contain keratin—provides waterproof barrier that helps prevent dehydration in dry airSnakes:-acute chemical sensors and lack eardrums— their sensitivity to ground vibrations help them detect movement-flicking tongue helps to fan odors toward olfactory organs on roof of mouth
28 Reproduction Sexual Female’s eggs fertilized internally Eggs, with a leathery and flexible shell, are then deposited
29 The Amniotic Egg extraembryonic membranes protect the embryo. gas exchange, waste storage, transfer of stored nutrients to embryoAmnion: a fluid filled cavity that cushions against shockIs not found in amphibians
30 Gas ExchangeWatertight skin (due to scales) not used as respiratory surface.Most rely solely on lungs for gas exchangeTurtles also use moist surfaces of cloaca.
31 Unique FeaturesSome lizards can lift their front legs off the ground while running
34 Body Cavity Body Symmetry Present (has coelom) Bilateral symmetry
35 Nervous System Present The central nervous system is composed of a brain, a spinal chord, and nerves.The autonomic nervous system controls heartbeat, breathing, and digestion.
36 Circulatory System Present Warm-blooded Heart pumps blood through body to give energy to all parts of the birdBirds have a four-chambered heart to keep tissues well supplied with oxygen and nutrients, supporting a high rate of metabolism.
37 Digestive System Present Beaks evolutionarily modified according to diet/environmentThe crop organ is unique to birds, stores food, continuously supplies small amounts of food to the stomachStomach has two parts: Proventriculus (secretes digestive juices) & Gizzard (gravel and muscles grind up food)Extremely high metabolism
38 Excretory System Two kidneys are the main excretory organs Birds lack a urinary bladderBoth liquid and solid wastes are excreted through cloaca
39 Locomotion/Musculature Wings (made of B-keratin) adapted for flightPower for flapping comes from contractions of the large pectoral attached to sternal keelSome birds have wings adapted to soar on air currents and flap their wings only occasionallyRatites = flightless birds (lack sternal keel and enlarged pectoral muscles)
40 Skeletal Type Internal skeleton Two legs and two wings Reduction in weight facilitates flight (no teeth, no jaw bones, reduced skull)Hollow bones make bones stronger, not lighterSternal keel allows for flight (not present in ratites)
41 Sensory Structures/Features Well developed mid brain -> acute visionExcellent sense of hearingReduced olfactory lobes -> poor sense of smellLarge Corpora Striata -> instinctive behavior (i.e. feeding, flying, reproduction, etc.)
42 Reproduction Sexual reproduction Eggs fertilized internally Eggs have protective shell
43 Reproduction (cont’d.) Birds engage in elaborate courtship rituals during breeding season
44 Gas Exchange Complex respiratory system Air goes into nostrils -> trachea -> syrinx -> bronchi -> lungs -> abdominal air sacs ->lungs -> other air sacs -> up the bronchi
45 Other Unique FeaturesWide range of feet and beaks, adapted to the environment and foodA bird’s brain is actually 10x larger than a non-bird reptile’s, and only slightly smaller than a mammal’s
46 QUIZ!Of the amphibians (frogs, salamanders, caecilians), which organisms use external fertilization?FrogsSalamandersCaeciliansBoth A and B
47 ANSWER: D(eggs of frogs and salamanders are fertilized outside the body while caecilians’ eggs are fertilized internally)
48 2. Platyhelminthes, birds, amphibians, and reptiles all possess: a. A true circulatory systemb. A true respiratory systemc. Bilateral Symmetryd. Coelome. A vertebrae
49 ANSWER: C(amphibians, birds, reptiles, and Platyhelminthes all have bilateral symmetry)
50 3. Which of the following are cold-blooded? A. AmphibiansB. BirdsC. ReptilesD. Both A and C
51 (amphibians and reptiles are cold blooded) ANSWER: D(amphibians and reptiles are cold blooded)
52 4. True or false: Amphibians use amniotic eggs in their reproductive process
53 (reptiles and birds use amniotic eggs) ANSWER: False(reptiles and birds use amniotic eggs)