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
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