2nd Semester 37 - BIOLOGY JUNCTION

AP Plant Study Guide-8b

Unit 8B – Plants

Know the following:

water potential of a turgid plant cell in pure water
adaptations of hydrophytes
what occurs if guard & surrounding epidermal cells are K+ deficient
how stomata are opened & closed
what must the plant expend for bulk flow of water in the root apoplast
which part of an oat seedling detects the direction of light
effect of gibberellins on the aleurone layer of seeds
how plant hormones determine the bending of plants toward light
what hormone might produce normal growth in a mutant dwarf plant
what can function as a sink in plants
why does photosynthesis decrease in wilting leaves
what are epiphytes
what is chlorosis
what soil characteristics would be the least productive to plant growth
what happens to most water taken up by a plant
how solutes move in plants according to the pressure-flow hypothesis of phloem transport
what causes guttation to occur
why does most of the water in xylem move upward in a tree
what property of water causes cohesion of its molecules
function of companion cells
what 2 elements make up most of the dry weight of plants
what could be the harmful effect of spraying a fungicide on a woodlot
what do carnivorous plants supplement by eating insects
why is nitrogen fixation so important
what would be characteristics of soil well suited for plant growth
what is the function of micronutrients in plants
what elements are micronutrients needed by plants
what elements are macronutrients needed by plants
what is meant by double fertilization
what are some “vegetables” that technically are fruits
why is sexual reproduction an advantage to plants
what is the megaspore mother cell & what does it do
what do male gametophytes produce in plants
name 4 flower parts that are modified leaves
what is the function of a seed’s radicle
what forms pollen on a plant
what do the 2 sperm nuclei fertilize in plants
what causes seed germination
what floral parts are involved in pollination & fertilization
what things can function in signal transduction in plants
what is needed by a short-day plant for it to flower
what type of tropism do vines use to grow toward tropical trees
why do plants use changes in photoperiods instead of air temperature changes to trigger dormancy
what is needed to get poinsettias to bloom early in December
do plant hormones act the same on all root & stem tissues
what hormone is involved in the rapid opening & closing of stomata
what effect do auxins have on stem cuttings that are to be rooted

AP Lecture Guide 18 – Microbial Models

AP Biology: CHAPTER 18

MICROBIAL MODELS

1. What makes microbes good models to study molecular mechanisms?

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2. List several characteristics of viruses.

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3. What are the two basic components of viruses? ___________________________________

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4. Use the diagram to help explain typical viral reproduction.

5. Identify the cycle used by the virulent phage.

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6. Compare the lytic and lysogenic cycles.

7. What is the role of the viral envelope?

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8. Outline the steps in the life cycle of the envelope viruses.

9. Review the life cycle of the HIV virus.

10. What is reverse transcriptase and why is it important in biotechnology?

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11. What is a vaccine?

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12. Where do emerging viruses come from?

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13. What is a viroid? Give some examples.

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14. What is a prion and what do they do to the cells?

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15. List and describe the three basic shapes of bacteria used for classification.

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16. Most bacteria are not pathogenic. Identify several important roles they play in the ecosystem

and human culture.

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17. How do variations arise in bacteria considering they reproduce mostly by asexual means?

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18. Define bacterial transformation.

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19. How does transduction differ from transformation?

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20. What is a plasmid and identify its role in bacterial conjugation?

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21. What is the major method utilized by bacteria to pass along resistance to antibiotics?

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22. What is a transposon?

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23. Describe potential problems caused by transposons.

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24. E. coli use a regulatory system called an operon. Identify the components with their functions of the operon.

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25. Use the diagram of the Tryp operon to outline how it regulated tryptophan levels.

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26. Describe how the trp operon is a repressible operon.

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27. Use the diagram of the lac operon to outline how it regulates glucose levels.

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28. Does the diagram above represent the condition for the absence or presence of lactose?

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29. Describe what happens when lactose is absent.

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30. How is the lac operon an inducible system?

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31. Summarize how the presence and absence of glucose influences the lac operon.

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AP Lecture Guide 26 – Origin of Life

AP Biology: CHAPTER 26: ORIGIN OF LIFE

1. Start with the origin of the earth and identify the time frame, conditions, and evidence for

each of the following steps leading to current life forms on earth.

a. Origin of the earth ________________________________________________________

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b. Prokaryotes _____________________________________________________________

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c. Oxidizing atmosphere _____________________________________________________

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d. Eukaryotic cells __________________________________________________________

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e. Multicellular life __________________________________________________________

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2. What was significant about the discovery of the iron oxide bands in the sedimentary layers.

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3. Describe the theory of endosymbiosis. ___________________________________________

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4. Why did evolution seem to slow 750 to 570 million years ago?

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5. What was special about the Cambrium Explosion?

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6. Describe a few adaptations essential for the invasion of plants onto land.

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7. Scientific Hypothesis for the origin of life

a. The first cells may have originated by chemical evolution on a young Earth

b. Abiotic synthesis of organic monomers is a testable hypothesis

c. Laboratory simulations of early-Earth conditions have produced organic polymers

d. RNA may have been the first genetic material

e. Protobionts can form by self-assembly

f. Natural selection could refine protobionts containing hereditary information

g. Debate about the origin of life abounds

8. Describe the hypothesized conditions on earth when life arose. _______________________

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9. What did Louis Pasteur demonstrate with his experiment? ___________________________

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10. List the four stages for the formation of life.

a. _______________________________________________________________________

b. _______________________________________________________________________

c. _______________________________________________________________________

d. _______________________________________________________________________

11. What metabolic processes would you expect to see in protobionts?

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12. Why is RNA now thought to be the first genetic code?

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13. What did Oparin, Haldane, Miller and Urey accomplish?

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14. What are some of the possible locations for the first life forms?

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15. What is the basis of the classification system developed by Linneaus?

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16. Why is taxonomy considered a work in progress?

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17. What are two problems with the five kingdom system of classification?

a. ________________________________________________________________________

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b. ________________________________________________________________________

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18. How has the Domain System altered our view of taxonomy?

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19. Which prokaryote is closer to the eukaryotes? List several reasons for your answer.

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20. Place the following metabolic processes in an order that fits this hypothesis for the origin of

life: Photosynthesis, Aerobic Respiration, Fermentation, Nucleic Acid replication (RNA or

DNA), Membrane transport

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21. Label the diagram to explain the Miller and Urey experiment to test the Abiotic Synthesis

hypothesis.

22. Label the diagram to indicate the major events, the time frame, and the geologic eras the

origin of life on Earth.

Algal & Fungal Protist

Algal & Fungal-like Protists
Kingdom Protista
All Materials © Cmassengale

Algal-Like Protists

Characteristics of Algae:

Plantlike members of the kingdom Protista
Eukaryotes
Most unicellular, but some multicellular
Autotrophic – contain chlorophyll & make food by photosynthesis
Plankton = communities of organisms, mostly microscopic, that drift passively or swim weakly near the surface of oceans, ponds, and lakes
Produce oxygen that is returned to the atmosphere
Range in size from microscopic to seaweeds hundreds of feet in length
Do not have true roots, stems, nor leaves
Form gametes (eggs & sperm) in single-celled gametangia (chambers) instead of multicellular gametangia like true plants
Found in freshwater, marine, and moist soil habitats
Most have flagella at some time in life cycle
Algae cells contain organelles called pyrenoids organelles that make & store starch

Structure of Algal Cells:

The body of algae is called the thallus (1n)
Algae may be unicellular, colonial, filamentous, or multicellular
Unicellular algae are single-celled & make up phytoplankton (a population of photosynthetic organisms that begins many aquatic food chains)
Phytoplankton make much world’s carbohydrates & are the major producers of oxygen

Chlamydomonas
Copyright © by Holt, Rinehart and Winston

Colonial algae consist of groups of cells working together
Some colonial algal cells may specialize for movement, feeding, or reproduction showing for division of labor

Volvox
Copyright © by Holt, Rinehart and Winston

Filamentous algae have slender, rod-shaped thallus arranged in rows joined end-to-end
Holdfasts are specialized structures in some filamentous algae that attaches the algae so it can grow toward sunlight at the surface

Spirogyra
Copyright © by Holt, Rinehart and Winston

Multicellular algae often have a large, complex leaf-like thallus & may have stem-like sections and air bladders
Macrocystis is among the largest multicellular algae

Macrocystis
Copyright © by Holt, Rinehart and Winston

Reproduction in Unicellular Algae:

Asexual Phase

Algae absorbs its flagellum
Haploid algal cell then divides mitotically from 2 to 3 times
From 4 – 8 haploid flagellated cells called zoospores develop in this parent cell
Zoospores break out of the parent cell & eventually grow to full size

Sexual Phase

Haploid cells dividing mitotically to produce either “plus” or “minus” gametes
A plus gamete and a minus gamete come into contact with one another, shed their cell walls, and fuse to form a diploid zygote
This resting stage of a zygote is called a zygospore & an withstand bad environmental conditions
When conditions are bad, the thick wall opens and the living zoospore emerges

Life Cycle of Chlamydomonas
Copyright © by Holt, Rinehart and Winston

Reproduction in Multicellular Algae:

Oedogonium is a multicellular, filamentous green algae with specialized cells called gametangia that form gametes
The male gametangia or antheridium makes sperm, & the female gametangia or oogonium makes eggs
Sperm are released into the water & swim to the egg to fertilize them
The fertilized egg or zygote is released from the oogonium & forms thick-walled zoospores
Zoospores undergo meiosis so one cell attaches to the bottom & develops a holdfast while the other zoospores divide & form a filament

Oedogonium Life Cycle
Copyright © by Holt, Rinehart and Winston

Spirogyra, another filamentous green algae, reproduces by conjugation

spirogyra conjugating.jpg (91550 bytes)

Two filaments align side by side, their adjacent cell walls dissolve, & a conjugation tube forms between them
Fertilization occurs when a + gamete cell moves through the tube & fuses to the – gamete cell
Zygote forms a thick walled spore (sporangium) that breaks away from the parent & forms a new filament

Spirogyra: conjugation begining.
Conjugation Tube between Spirogyra

The leaflike algae Ulva has a sexual reproductive cycle characterized by a pattern called alternation of generations
Alternation of generations has two distinct multicellular phases- a haploid, gamete-producing phase called a gametophyte and a diploid, spore-producing phase called a sporophyte
Alternation of Generation also occurs in more complex land plants, but the gametophyte & sporophyte do not resemble each other

Ulva Life cycle
Copyright © by Holt, Rinehart and Winston

Classification:

Algae are classified into 7 phyla, based on color, type of chlorophyll, form of food-storage substance, and cell wall composition
All phyla contain chlorophyll a
All algae live in water or moist areas (ponds, seas, moist soil, ice…)
Act as producers making food & oxygen
Many species of algae reproduce sexually and asexually
Sexual reproduction in algae is often triggered by environmental stress

SEVEN PHYLA OF ALGAE
Phylum	Structure of Thallus	Pigments	Food Storage	Cell Wall composition
Chlorophyta (Green Algae)	Unicellular Colonial Filamentous Multicellular	Chlorophyll a & b Carotenoids	Starch	Mainly Cellulose
Phaeophyta (Brown Algae)	Multicellular	Chlorophyll a & c Carotenoids Fucoxanthin Peridinin	Laminarin	Cellulose Algin
Rhodophyta (Red Algae)	Multicellular	Chlorophyll a Phycobilins Carotenoid	Starch	Cellulose CaCO3
Bacillariophyta (Diatoms)	Unicellular Some Colonial	Chlorophyll a & c Carotenoids Xanthophyll	Starch	Pectin SiO2
Dinoflagellata (Dinoflagellates)	Unicellular	Chlorophyll a & c Carotenoids	Starch	Cellulose
Chrysophyta (Golden Algae)	Unicellular Some Colonial	Chlorophyll a & c Xanthophyll Carotenoids	Laminarin	Cellulose
Euglenophyta (Euglenoids)	Unicellular	Chlorophyll a & b Carotenoids Xanthophyll	Paramylon	No Cell Wall Pellicle

Chlorophyta (green Algae):7000 species

May be unicellular, multicellular, or colonial
Include Spirogyra, Ulva, & Chlamydomonas
Contain chlorophyll a & chlorophyll b and carotenoids (orange & yellow pigments) as accessory pigments
Store food as starch
Cell walls mainly cellulose, but some marine forms add CaCO3
Habitat may be freshwater, moist surfaces, or marine environments
Some have whip-like flagella for movement
May live symbiotically as lichens
Thought to have given rise to terrestrial plants

Phaeophyta (brown algae):1500 species

Contain chlorophyll a & chlorophyll c and fucoxanthin (brown pigment) as accessory pigments
Most are multicellular growing in cooler marine habitats
Include kelps & seaweeds
Largest protists
Specialized rootlike holdfasts anchor thallus to rocks
Specialized air bladders keep leaflike blades afloat near surface to get light for photosynthesis
Stemlike structures are called the stipe and support the blades
Store food as a carbohydrate called laminarin
Include Laminaria & Fucus


Laminaria	Fucus

Macrocystis or giant kelp contains algin in its cell walls which is used in cosmetics, some drugs, ice cream, etc.

Rhodophyta (red algae):4000 species

Multicellular algae that mainly grow deep in warm marine waters
Some freshwater species exist
Highly branched thallus
Contain chlorophyll a & phycobilins (red pigments) to trap sunlight for photosynthesis

Polysiphonia (red algae)

Store food as starch
Cell walls contain cellulose and agar (used as a base in culture dishes to grow microbes)
Some species contain carageenan in their cell walls used for gelatin capsules & in some cheeses

Bacillariophyta (diatoms):11,500 species

Abundant in marine & freshwater habitats
Called phytoplankton & start many aquatic food chains
Contain chlorophyll a & c, carotenoids (orange pigments), & xanthophyll (yellow pigments)
Store food as starch & contain mainly cellulose in their cell walls
Lack cilia & flagella
Have glass like shells or valves containing SiO2 that fit together in 2 parts

Diatoms
Copyright © by Holt, Rinehart and Winston

Centric diatoms are marine & have circular or triangular shells
Pennate diatoms are found in freshwater & have rectangular shells
When diatoms die, they form a layer called diatomaceous earth that is abrasive and used in detergents, toothpaste, fertilizers, etc.

Dinoflagellata or Pyrrophyta (dinoflagellates):1100 species

Major producers in marine habitats
Small, unicellular organisms making up plankton
Many are photosynthetic, but some are colorless heterotrophs
Photosynthetic dinoflagellates are yellow to brown in color due to chlorophyll a & c and carotenoids

Have 2 flagella that spin and move the dinoflagellate through water

Store food as starch
Some dinoflagellates are covered with armor like plates & spines made of cellulose
Often undergo algal blooms where their numbers greatly increase
Produce a toxic substance and cause poisonous red tides (water appears red due to red pigments in the dinoflagellates)

Red Tide

Some such as Noctiluca can produce light by bioluminescence

Photograph by Robert Brons

Chrysophyta (golden algae)850 Species:

Most are live in freshwater habitats, but some are marine
Unicellular algae containing chlorophyll a & c and the brown pigment fucoxanthin and carotenoids
Many have flagella for movement
May be naked or have cellulose cell walls or silica scales or shells
May form highly resistant cysts to survive beneath frozen lake surfaces in winter

Euglenophyta1000 Species:

Unicellular algae that lack cell walls
Have a flexible protein covering called the pellicle
Called euglenoids
Possess chlorophyll a & b and carotenoids
Store food as paramylon (polysaccharide)
Most live in freshwater, but some live in moist soil & the digestive tracts of certain animals

Euglena is a common euglenoid found in freshwater
a. Elastic, transparent pellicle below cell membrane
b. Contractile vacuole to pump out excess water
c. Chloroplasts to make food by photosynthesis
d. Can be heterotrophic in the absence of light

Fungal-Like Protists

Characteristics of Fungal Protists:

Includes cellular slime molds, plasmodial slime molds, & water molds
Unique life cycles with two phases
Multicellular, heterotrophic organisms
Little tissue specialization
Usually small & live in moist or watery habitats
Act as decomposers breaking down dead organic matter

Slime molds:

Shiny, wet appearance
Often brightly colored (yellow or orange)
Have unique life cycles with 2 phases — a mobile feeding stage & a nonmotile reproductive stage

Fungal-like in nutrition (absorptive heterotrophs that break down dead organic matter)
May be saprophytes or parasites

Saprophytic Slime Mold

Multinucleate body mass
May have a mobile, ameba-like feeding stage
Make a reproductive structure or fruiting body that produces spores
Often found on decaying wood or leaves

some slime mold fruiting bodies
A is Lycogala epidendrum, B is Comatricha typhoides, C is Badhamia utricularia, D is Dictydium

Two groups of slime molds exist — Cellular slime molds & Plasmodial slime molds
Cellular Slime Molds (Phylum Acrasiomycota)
Plasmodial Slime Molds (Phylum Myxomycota)

Acrasiomycota (Cellular Slime Molds):

Alternate in their life cycle between amoeboid feeding stage & spore-producing fruiting body

Live in freshwater, moist soil
Clump together into masses called pseudoplasmodium whenever little food is available

Cells in the pseudoplasmodium are independent but move together “slug-like”
Pseudoplasmodium settles & forms fruiting body with spores
Spores spread by wind to new location & form individual amoeboid feeding stage

Myxomycota (Plasmodial Slime Molds):

Exist as a plasmodium ( a mass of cytoplasm with many nuclei)
Plasmodium creeps along over decaying material

Decomposes & absorbs plant material as food
When food is scarce, the plasmodium forms stalked fruiting bodies with spores that are resistant to bad environmental conditions
When conditions turn favorable, spores form a new plasmodium

Oomycota (Water Molds):

Fungal-like organism made of branching filaments with cell walls of cellulose

Branching Filaments of Water Mold

Aquatic water molds are parasites on fish forming furry growths on their gills
May act as decomposers in water of dead plants & animals
May be pathogenic to plants
e.g. Phytophthora infestans caused blight in potatoes (Irish Potato Famine in 19th century)
Blight in plants decays & discolors stems & leaves

Blight on Leaves & Potatoes

Water molds reproduce sexually & asexually
Motile zoospores are asexually produced from reproductive structures called sporangium
In sexual reproduction, cells with eggs form tubes to cells with sperm to fertilize & form new branching filaments

Chytridiomycota (Chytrids):

Aquatic protists that form gametes & zoospores
Most are unicellular or filamentous

May be saprophytes (decomposers) or parasites on algae, plants, or insects
May be a link between protists & fungi

BACK

Amphibian

Amphibian Evolution:

	Arose from lobe-fined ancestor called Crossopterygians
	Land plants & insects provided new food source
	Had primitive lungs & short, limb like fins for short periods on land
	Appeared during late Devonian
	Icthyostega early amphibian with 4 limbs, lungs, & a tail for swimming

Adaptations:

	Four limbs with claws on digits (toes)
	Lungs instead of gills
	Both internal & external nares (nostrils)
	Three chambered heart (two atria & one ventricle)
	Double loop blood circulation to lungs & rest of body cells

	Skin with keratin (protein) to prevent water loss
	Necks to more easily see & feed
	Most with smooth, moist skin to take in dissolved oxygen
	Some with oral glands to moisten food they eat
	Webbed toes without claws
	Ectothermic – body temperature changes with environment
	Show dormancy or torpor (state of inactivity during unfavorable environmental conditions)
	Hibernate in winter and aestivate in summer
	Aquatic larva called tadpole goes through metamorphosis to adult
	Metamorphosis controlled by hormone called thyroxine

American Toad Tadpole photograph
Tadpole

	External fertilization with amplexus (male clasps back of female as sperm & eggs deposited into water)
	Eggs coated with sticky, jelly like material so they attach to objects in water & do not float away
	Eggs hatch into tadpoles in about 12 days

Eggs

Males with vocal sacs to croak
Digested system adapted to swallow prey whole
Well developed muscular system

Classification:

Anura – frogs & toads
Urodela – salamanders & newts
Apoda – caecilians
Trachystoma – sirens or mud eels

Anuran Characteristics:

Both terrestrial & freshwater species
Tadpole with tail, gills, & two-chambered heart
Adults without a tail, four limbs, & lungs
Frog skin smooth & moist for cutaneous respiration, while toads is rough & warty (poison glands)

Frog

Toad

Long hind limbs for jumping
Long, forked tongue hinged at front of mouth

Urodela Characteristics:

Includes salamanders & newts
Have elongated bodies with a tail & four limbs
Smooth, moist skin for cutaneous respiration
Less able to stay on dry land than anurans

Spotted salamander photograph
Spotted Salamander

Size from a few centimeters long to 1.5 meters
Nocturnal when live in drier areas
Newts are aquatic species

red-spotted newt photograph
Red Spotted Newt

Lay eggs in water or damp soil
Some bear live young
May or may not go through tadpole stage (some hatch & look like small adult)

Apodan Characteristics:

Includes caecilians
Tropical, burrowing, worm like amphibians
Legless
Small eyes & often blind
Eat worms & other invertebrates
Average length 30 centimeters, but can grow up to 1.3 meters
internal fertilization
Female bear live young

Caecilian

Trachystoma Characteristics:

Includes mud eels or sirens
Known as “rough mouth” amphibians
Found in eastern U.S. & southern Europe
Have minute forelimbs & no hindlimbs

Mud Eel or Siren

External Frog Anatomy:

Live double life on land & water
Powerful hind legs for jumping & swimming fold under body when at rest
Bulging eyes to stay submerged but still see predators
Blinking eyelids protect eyes from dust & dehydration
Nictitating membranes clear to moisten eye & see underwater
Internal nostrils or nares allow frog to breathe underwater
Tympanic membranes or eardrums behind each eye transmit sound through bone called columella to inner ear
Eustachian tubes connect mouth & middle ear to equalize pressure

Males croak or make sound to attract females & ward off other males
Have protective coloration from cells called chromatophores
Granular glands secrete foul tasting or poisonous substance
Mucus glands lubricate skin for oxygen to be dissolved & absorbed

Internal Frog Anatomy:
Skeletal System

Nine spinal vertebrae (1 cervical in neck, 7 trunk, & 1 sacral supporting hind legs)
Urostyle long, slim bone connecting sacral vertebrae & trunk
No rib cage, but pectoral girdle forms shoulders & connects front legs
Pelvic girdle connects to hind legs

Digestive System

Tongue sticky, forked, & hinged at front of mouth so can be extended out to catch insects
Can pull eyes inward to help swallow food
Two, sharp, backward-pointing vomerine teeth in roof of mouth help prevent prey from escaping
Maxillary teeth line the edge of the upper jaw
Alimentary canal (mouth, esophagus, stomach, small & large intestines, and cloaca) is where food is digested, absorbed & wastes eliminated
Stomach makes gastric juices to break down food
Pyloric sphincter muscle controls movement of food from stomach into first part of small intestine called duodenum
Liver makes bile to digest fats; stored in gall bladder
Pancreas makes pancreatic juice to digest food in small intestine
Ileum is coiled mid portion of small intestine
Mesentery is a fanlike membrane holding the intestine in place
Wastes collect in large intestine & then move into cloaca along with eggs, sperm, & urine until they leave body through the anus

Circulatory System

Need more oxygen to burn increased amount of food needed to live on land
3 chambered heart (right atrium receives deoxygenated blood from body, left atrium receives oxygenated blood from lungs, & ventricle pumps blood to lungs & rest of the body)
Double loop blood circulation (pulmonary from heart to lungs & systemic from heart to rest of body)
Conus arteriosus carries blood from ventricle to body cells

Respiratory System

Tadpoles use gills to breathe
Adult frogs breathe through lungs & moist skin (cutaneous respiration)
Glottis is the opening into throat & lungs

Excretory System

Carbon dioxide excreted through skin & lungs
Kidneys filter blood & store urine in urinary bladder until leaves cloaca

Nervous System

Olfactory lobes at base of brain detect smells
Cerebrum behind olfactory lobes controls muscles
Optic lobes detect sight
Cerebellum controls balance & coordination
Medulla oblongata controls heart rate & breathing
Cranial nerves connect brain & spinal cord, while spinal nerves branch off the spinal cord to muscles & sensory receptors

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SEVEN PHYLA OF ALGAE