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Chapter 32

• An Introduction to Animal Diversity

Animals are Multicellular,

Heterotrophic, Eukaryotic, Metazoans

1. Heterotrophs

• Ingest organic materials (food)

• Living food, or deadWhich of these heterotrophs is in Kingdom: Animalia?

400X magnification

2. Animal Cells

• Eukaryotic

▫ Nucleus with DNA

bacterial cell animal cell

Nuclear membrane

• No cell wall (unlike plants and fungi)

▫ Collagen (structural protein) holds cells together

• Specialized cells include muscle and nerve

▫ Allows animals to coordinate activities and move

Animal Development

• Sexual reproduction (most)

1. Sperm + egg zygote (fertilized egg)

2. Cleavage of zygote blastula (hollow ball of ~ 100 cells)

3. Gastrulation process forms gastrulaforms layers of embryonic tissue (germ layers)

Animal Development

larva

Some animalsLarvametamorphosisjuvenile adult

Larva = immature, distinct from adult

Advanced animals mature into adult

I. History of Animals spans 0.5 billion years

• All animals share a common ancestor

• Paleozoic era (550 – 250 mya) ▫ Precambrian Algae, jellyfish

▫ Cambrian explosion ~520 mya Arthropods, chordates, echinoderms

• Mesozoic era (250 – 65 mya) ▫ Existing animal phyla evolved into new habitats

• Cenozoic era (65 mya – present)▫ Mammal herbivores and predators

II. Animals have body plans• Body plan

▫ Set of morphological and developmental traits organized into a functioning body

• Symmetry▫ No symmetry ex. Sponges = primitive animals

▫ Radial symmetry =

sea anenome, jellyfish

▫ Bilateral symmetry

2 sided

Note: starfish larvae are bilateral

Tissues

• Tissue – collection of specialized cells working together to perform a function

▫ Porifera (sponges)– lack true tissue

▫ Eumetazoans have 2 - 3 embryonic tissue types

Ectoderm

Endoderm

Mesoderm (in animals with bilateral symmetry)

Cnidaria Corals have 2 embryonic tissues / Platyhelminthes flatworms have 3

Eumetazoans have true tissues

3 layers of embryonic tissue in blastula

Body Cavities

• Coelom = fluid filled space that separates digestive cavity from body wall

▫ In animals with 3 germ layers

Not sponges, not cnidarians

▫ Cushions suspended organs

▫ Allows organs to move and grow independent of body wall

Coelomates include Annelida, Arthrpodoa, Echinodermata Chordata

1. True coelom develops from mesoderm

2. Pseudocoelomate

Coelom forms partially from mesoderm and endoderm

Nematoda roundworm

3. Acoelomate

Lack a coelom

Platyhelminthes flatworm

Protostome - blastopore becomes mouth

Deuterostome – blastopore becomes anus

(Chordata, Echinodermata)

Summary

1. All metazoans (animals) share a common ancestor

2. Sponges are the most primitive

3. Eumetazoans have true tissues

4. Most animals are in Bilatera

Bilateral symmetry and 3 germ layers

5. Chordates and echinoderms are deuterostomes

Chapter 33 Invertebrates

No backbone

95% of known animal species

CHOANOFLAGELLATES ([protista)

PHYLUM CALCARIA/SILICEA (polyphyletic)

• Sponges

• Suspension feeders▫ Water w/food particles drawn through

body

• Sessile adult

• Lack true tissues

larva

PHYLUM Cnidaria

• Jellies, corals, hydras, anenomes

• Radial symmetry

• 2 germ layers

• Polyp and medusa forms

• Predators

▫ Tentacles with cnidocytes

Medusa form is free swimming

• Nerve net controls movement (no brain)

• Gastrovascular cavity with single opening

CLADE BILATERA

• Bilateral symmetry

• 3 embryonic germ layers

• Coelomates (most)• Arose Cambrian explosion

PHYLUM PLATYHELMINTHES (flatworms)

• Acoelomate

▫ Lack a body cavity

• 3 germ layers

• brain

• Protostome

▫ Blastoporemouth

• Many parasitic

Planaria

Fluke causes schistosomiasis in 200 million people

tapeworm

PHYLUM MOLLUSCa

• Chitins, snails, slugs, abalone, clams, octopi, squid

• Coelomates• 3 main body parts

▫ Muscular foot- for movement▫ Mantle – may secrete shell▫ Visceral mass – has organs

• Open circulatory system• Protostome

▫ Blastoporemouth

Chiton

8 plate shell, attached to rocks, use radula to scrape algae

Gastropods

Torsion – rotated visceral mass so that anus is above head

No radula, no distinct head, hinged shell, adductor muscles, gills for feeding and gas exchange, excurrent siphon, suspension feeders

Bivalves

Cephalopods

Phylum Annelida (segmented

worms) • earthworms, sandworms, leeches

• Coleomate

Clade Bilatera Ecdysozoa

• Arthropods, nematodes

• DNA evidence

• External cuticle molts

PHYLUM NEMATODA = unsegmented

roundworms

• Pseudocoelomate

C. Elegans Trichinella

• Coelomate

• Segmented body plan

• Jointed appendages

• Exoskeleton (protein, chitin)

▫ Molt

• Well developed sense organs

• Gas exchange

• Open circulatory system with hemolymph

Isopods are terrestrial

Bilatera Ecdysozoa

Phylum ARTHROPODA Arachnids

Horseshoe crab

Bilatera Ecdysozoa

Phylum ARTHROPODA Myriapods• Millipede, centipede

Insects have 3 pairs of legs, some have wings, some undergo metamorphosisSexual reproduction, some are pests, some transmit disease,

Bilatera Ecdysozoa

Phylum ARTHROPODA Insects

Subphylum Hexopoda

• Deuterostome

▫ Blastopore develops into anus

• Coelomates

Bilatera Deuterostomia Phylum

EchinodermataSea stars, urchins, sea

cucumber

Water vascular system and tube feet for locomotion, feeding and gas exchange

Phylum Chordata

• Chordates have 4 shared embryonic characteristics

1. Notochord (mesodermal cells)

Flexible rod between gut and nerve cord

Skeletal support

In vertebrates bony skeleton

in humans persists as intervertebral discs

Lost in most adult chordates

Tunicate larva, sea squirt

2. Dorsal hollow nerve cord (ectoderm)

develops into brain, spinal cord (so this feature is retained in adults)

Lancelet Branchiostomata, a cephalochordate

3. Pharyngeal clefts

▫ pouches and grooves

▫ allow water to enter/exit without passing through digestive tract

develop into gill slits for feeding, gas exchange

Role in ear , neck development in tetrapods

amphioxus fish human

▫ 4. Post-anal tail

Invertebrate chordates

• No vertebral column, notochord found in adults

• Lancelets and tunicates

Lancelet, eaten in AsiaRetain 4 characteristics Sea squirt 3,000 speciesas adults retain the gills but larvae have

all 4

Craniates = chordates with a head• Derived characters:

Neural crest cells teeth, skull bones, dermis of face, some

neurons

Craniates have a skull

• Hagfish

▫ Partial skull, invertebrate, no jaws, no scales

Infraphylum Myxnidiae

subphylum

Vertebrates have a backbone

• Vertebrae enclose spinal cord (subphylum Vertebrata)

Infraphylum Vertebrata

Jawless vertebrates: Lampreys

Class Petromyzontiformes

•Sucker mouth, predators, primitive, head but no skull, cartilage skeleton

http://www.glfc.org/slft.htm

• Fishes are aquatic, gill-breathing vertebrates that usually have fins and skin covered with scales.

• (lamprey and hagfish are fish, but do not have scales)

Gnathostomes

• Have jaws

• 1. Chondricthyes fish have a cartilage skeleton

▫ Sharks, rays – most carnivorous

Class Chondricthyes

• 2. Ray-finned fishes

• Bony skeleton, bony scales

• Swim bladder for buoyancy

Move gas from blood to bladder rise

Class Osteoicthyes

3. Lobe-finned fish – no swim bladder, lungs and gills

lungfish

http://en.wikipedia.org/wiki/File:Lungs_of_Protopterus_dolloi.JPG

Lung of a lungfish, they also have gills. Can live out of water for months

3. Tetrapods have limbs

Evolved from a branch of lobe-finned fish

Neck vertebrae

Amphibians

Salamaders, frogs, toads, salamanders, caecilians

Require water for part of life

External fertilization

Class Amphibia

Amniotes are tetrapods that have

a terrestrially adapted egg

Reptiles, birds, mammals

• Amniote egg has 4 specialized membranes

• Amnion membrane ▫ fluid bathes embryo▫ Shock absorber

• Adaptation for terrestrial life

• Reptiles and birds have shell to protect egg

▫ Prevents dehydration

▫ Mammalian egg develops in body

• Allows embryo to develop on land

• Adaptations for terrestrial life

▫ Amniote egg

▫ Rib cage to ventilate lungs (frogs use throat)

reptiles

•Lizards, snakes, turtles, crocs, birds (!)• Keratin scales to protect

•Injury•Dehydration

•Internal fertilization

•Most reptiles are ectothermic•(obtain heat from environment)

•Birds are endothermic

•Internal fertilization

• Birds, are they reptiles?

• Flight adaptation▫ Wings, feathers

Like crocs and some dinosaurs, are archosaurs

• Mammals have mammary glands (females)

• Hair

• Endothermic• Differentiated

teeth

•Monotremes lay eggs

•Marsupials give birth to embryo

•Eutherians have placenta

Xenarthra Tubulidentata Sirenia

Lagomorpha Proboscidea Monotremata Marsupialia

HyracoideaCarnivora

Artiodactyl Cetacea Perissodactyla

Chiroptera Rodentia Primates Eulipotyphla

Primates include monkeys and apes (also,

lemurs, tarsiers)

Chapter 40 Principles of Animal

Form and Function

Terms

• Anatomy – form

• Physiology – function

• Natural selection favors variations that best fit environment

• Variations are genetic and inherited

I. Animal form and function are

correlated at all levels of

organization

1. Physical constraints on size and shape

• Shape example: in water, bump on surface of animal causes drag. Tapered body to swim fast to overcome drag

Convergent evolution

50 mph

2. Exchange needs with the environment influence body plan

▫ More surface area = more exchange

Every cell has access tosuitable environment

HydraAmoeba

Surface to volume ratio must be high cells are small

• Cell surfaces are bathed in interstitial fluid

▫ Bring nutrients, oxygen, rid of wastes

3. Hierarchical organization Cell tissue organ organ system organism

4 categories of animal tissues

• Epithelial tissue lines organs and cavities, composes glands

• Connective tissue binds and supports

• Muscular tissue for movement

• Nervous tissue for communication

Epithelial tissue for linings

• Tightly packed cells

• Simple epithelium is 1 layer for secretion and absorption

• Stratified epithelium is multiple layers for protection

cervix

skin

•Apical surface faces a lumen or outside•Basal surface attached to underlying tissueLUME

N

Connective tissue

• Cells sparsely scattered

• Extracellular matrix of protein +

▫ Plasma (blood)

▫ Mineralized (bone)

▫ Gel (cartilage)

• CT also includes adipose CT, fibrous CT, loose CT

Muscle tissue

• Contraction

Nervous tissue• Senses stimuli

• Transmit nerve impulses

• Brain, spinal cord, nerves

4. Coordination and Control =

endocrine + nervous systemsEndocrine system

Gland produces hormone into bloodstream

Target tissue responds

Examples: adrenalin, insulin, estrogen

Long lasting effects

Endocrine control

Only cells with receptorsrespond

Nervous system =nerve impulses through nerves to:

• Other neuron

• Muscle

• Gland

Fast

II. Feedback Control Loops

Maintain Homeostasis• Regulator animal

▫ Ex. river otter’s body temp is constant even when water T changes

• Conformer animal

▫ Ex. Bass (fish) conforms its internal T to T of the lake

• Homeostasis

▫ Steady internal state

Ex. humans

Body T

Blood volume

Blood pH

Glucose concentration in blood

Negative feedback – response lessens stimulus

Stimulus receptor response body returns to set pointExercise nervous system sweating cool body T

Positive feedback

Amplify the stimulus

Ex. childbirth

III. Thermoregulation• Critical for homeostasis

▫ body enzymes work at certain temperatures

▫ each animal has optimal T range

Heat loss in water is about 27 times faster than in air at the same temperature

• Endothermic = birds, mammals

▫ Generate body heat via metabolism

▫ Can dump body heat by sweating, large ears etc.

Staying in water helps dump heat

• Ectothermic = fish, lizards, snakes, frogs

▫ Heat source environmental

▫ Behavioral adaptations

Note: Sea lion obtain heat by raising flippers out of the water -technically, that’s ectothermic!

Strategies to regulate heat gain and loss

1. Integumentary system adaptations (skin)▫ Insulation

Fat Raise fur or feathers to trap air

▫ Secrete oil on feathers to repel water▫ Cooling by sweat, panting (evaporative)

2. Circulatory system adaptations

▫ Blood vessel dilation at skin to cool body

▫ Blood vessel constriction to warm body

▫ Counter current exchange in some animals

Blood in artery warms blood in vein

Reduces heat loss

3. Behavioral adaptations▫ Amphibians seek moist, warm environment▫ Reptiles move around during the day▫ Insects orient toward sun

4. Thermogenesis = heat productionex. shivering, movement

5. Acclimitizationthicker coat, enzyme expression

Ex. arctic flounder/antifreeze

Chapter 41: Animal Nutrition

Terms

Herbivore

Carnivore

Omnivore

Diet must supply energy and essential

nutrients• Essential nutrients

• 1. Essential amino acids (humans require 8)tryptophan, lysine, methionine, valine, leucine, isoleucine, threonine,

phenylalanine

Need all 20 to synthesize proteins

Complete protein – contains all essential aa ex. meat, eggs

Incomplete protein – eat with others to obtain all aa

2. Essential fatty acidsOmega- 3 and omega-6 (alphalinoleic and linoleic)

Seeds, grains, vegetables

3. Vitamins

13 organic molecules required in small amounts (humans)

Ex. A, Bs, C, D, E, K

Richard Smithells of the Univ. of Leeds examined the effect of

prenatal vitamins on neural tube defects in their infants. All women

in the study had a previous child with a neural tube defect. Half the

women took vitamins at least 4 months before trying to get pregnant.

The other half either were already pregnant or declined the

vitamins. The number of neural tube defects in the infants were

counted

4. Minerals are inorganic, require small amounts

Ca, Fe, Na, Zn, Mg, Cu, S, Cl, P

• Calories – from fats, protein, carbohydrates

• Water (not a nutrient)

Stages of food processing

• Ingestion

▫ eating

• Digestion

▫ Break down food mechanically and chemically

• Absorption

▫ Nutrients absorbed into bloodstream cells

• Elimination

▫ Solid wastes

Comparative study

1. Some animals have a gastrovascular cavity

one opening

Cnidaria (hydra) Platyhelminthes flatworm (planaria)

Some have a complete digestive tract

= alimentary canal = tube with compartments

Annelida

2. Animals with teeth have dental adaptations

• Carnivore - tearing

• Herbivore - grinding

• Omnivore - unspecialized

3.Some animals have very long alimentary canal to digest vegetation (plant cell walls)

Fibrous eucalyptus leaves

4. Some animals have mutualistic relationships with other animals for digestion

Ex. Ruminants have bacteria to digest cellulose

sugar for both bacteria and cow

bacteria use sugar to produce vitamins

4-chambered stomach, eat grass rumen and reticulum (has protists and bacteria) chew cud abomasum swallow cud omassum

• 5. Some animals engage in corprophagy

▫ rabbits obtain nutrients from feces after bacteria in large intestine ferment

Chapter 46

Reproduction

Reproduction in animals

• Sexual reproduction

▫ Haploid gametes fuse zygote

▫ female gamete = ? - large, non-motile

▫ male gamete = ? - small, motile

• Asexual reproduction

1. Fission = separation into 2 same sized individuals

2. Budding

Cnidarians – hydra, anemone, coral can also reproduce sexually under certain conditions

3. Fragmentation and regeneration

piece breaks off, regenerates whole animal

Sexual and asexual repro: Planaria (flatworm) Echinoderm

4. Parthenogenesis – egg develops without fertilization

Ex. some bee, lizard species

Usually reproduces sexually

Reproductive Cycles

1. Ovulation seasonal

release mature eggs, controlled by hormones

promotes offspring survival

ex. sheep

Ovulate late fall 5 mos lamb in spring

Or, monthly, as in humans

Ex. Daphnia

2. Two egg types

for fertilization (response to environmental stress)

for parthenogenesis (summer)

Crustacean (Phylum Arthropoda)When summer is over, some of the eggs develop into the small males which fertilize eggs

3. Hermaphroditism

1 individual with male and female reproductive system

any two individuals can mate

4. Sex reversal

individual changes sex during lifetime

Ex. wrasse lives in group with one male. When male dies, the largest female becomes male

Fertilization = sperm + egg

1. External fertilization

▫ Spawning

Female releases eggs, males sperm into environment

▫ Requires moist environment

▫ Some animals do not require physical contact

▫ Controlled by cues

Environmental – temperature, day length, lunar

Courtship

▫ Large number offspring, few survive

Chordata Vertebrata Amphibia

2. Internal fertilization

• Adaptation for dry environment

• Deliver sperm to egg internally

• Require copulation

• Mates attracted by pheromones

▫ Chemicals released into environment

• Fewer offspring, more resources invested

Survival of offspring in sexual

reproductionStrategies

1. calcium/protein eggshell prevents dehydration

▫ Birds, reptiles,

Mexican bearded lizard

• 2. Embryo develops internally

▫ Humans, kangaroos

• 3. Parental care

▫ Birds, mammals, (others)

Gamete production• Gonads

▫ Organs that produce gametes

▫ May be indistinct with gametes shed

Ex. Annelida

▫ May have testes and ovaries to produce sperm, egg

Spermatogenesis

Oogenesis

Chapter 13 Meiosis

Chapter 13 Meiosis

• Terms▫ Heredity Transmission of traits to offspring

▫ Variation Genetic variation in population

▫ Genetics Study of heredity

▫ Genes DNA coded information for protein

▫ Gametes Sperm and egg (and spores)

sexual reproduction

• 2 parents give rise to genetically unique offspring

Sexual Life Cycles

• Life cycle – from conception to production of offspring

• Somatic cells (body cells)

▫ 46 chromosomes

▫ 23 homologous pairs 2n (diploid) = 46

Same size

Same gene loci

Same centromere position

One set from mother, one set from father

Arranged in homologous pairs

Autosomes = pairs 1 – 22

Sex chromosomes = pair 23

XX = femaleXY = male

• Germ line cells – ovary/testes

▫ 1n (haploid) = 23

Fertilization 1n + 1n = 2n

Ex. Fruit fly egg has 4 chromosomes (1n). How many chromosomes in a sperm? A fly larval cell? An adult somatic cell?

Sperm + egg--- zygotefertilization

Haploid diploid haploid diploid etc………….

Animals BIO102

I. Interphase

• Note: nuclear membrane, chromatin, centrioles, microtubules

• Chromosomes (DNA) replicate to form sister chromatids

• Sister chromatids identical

• #individual chromatids in a human cell once DNA has replicated?

• How many chromosomes?

II. Meiosis

• Cell division to produce unique haploid gametes

• Occurs in germ cells of plants, fungi, animals

• Maintains constant # of chromosomes in species

Stages of Meiosis

• Prophase I

▫ Nuclear envelope breaks down

▫ Chromosomes (sister chromatids) condense

The diploid number of this cell is 6

Prophase I (continued)

▫ Spindle forms

▫ Centrioles migrate to poles

▫ Crossing over

Non -sister chromatids exchange

• Metaphase I

▫ Homologs line up on metaphase plate

▫ How many sister chromatids participate in each “tetrad”?

▫ How many chromosomes are present?

• Anaphase I

Homologs separate and move towards opposite poles

Note: sister chromatids connected

• Telophase I

▫ Each half of cell has a haploid set of chromosomes

▫ cytokinesis

Division of cytoplasm

2 haploid daughter cells

# chromosomes in each cell?

• Meiosis I is called reduction division

Each cell has 1 set of chromosomes

Meiosis II

• Prophase II

▫ spindle forms

• Metaphase II

▫ Sister chromatids line up on metaphase plate

Note: not identical

▫ microtubules attach to centrioles

• Anaphase II

▫ Sister chromatids separate

▫ chromosomes move towards opposite poles

Cohesions at centromere cleave

Telophase II

▫ Nuclei form around each haploid set

cytokinesis

• 4 genetically unique haploid cells

Meiosis and genetic variation

1. crossing over

2. independent assortment

3. sexual reproduction

1. Crossing over during prophase I

• Synapsis• Synaptonemal complex

▫ Zips up homologous chromosomes (sister chromatids)

• Crossing over▫ Between non-sister chromatids

• Chiasmata▫ X observed after crossing over

unique gametes due to recombinant chromosomes

2. Independent assortment

• example: a male fruit fly has 8 chromosomes, 4 pairs, 1 set from mom, one from dad

• Independent assortment 8 million combinations in a cell of 46 chromosomes

Overview of Meiosis