Animals and animal diversity
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Animals and Animal Diversity. The Nitty-gritty!. Note:. There is no red on this powerpoint, all non-essentials were deleted from the notes. Just imagine that everything is in red!. Ch 32?. Basic Characteristics. Multicellular Heterotrophic Mobile Eukaryotic Lack cell walls

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Animals and Animal Diversity

The Nitty-gritty!


Note:

  • There is no red on this powerpoint, all non-essentials were deleted from the notes.

  • Just imagine that everything is in red!


Ch 32?

Basic Characteristics

  • Multicellular

  • Heterotrophic

  • Mobile

  • Eukaryotic

  • Lack cell walls

  • Bodies are held together by structural proteins like collagen

  • Nervous and muscular tissue unique to animal kingdom


Reproduction and Development

  • Most reproduce sexually, with the diploid stage usually dominating the life cycle

  • After a sperm fertilizes an egg, the zygote undergoes rapid cell division called cleavage

  • Cleavage leads to formation of a blastula

  • The blastula undergoes gastrulation, forming a gastrula with different layers of embryonic tissues

Video: Sea Urchin Embryonic Development


Fig. 32-2-3

Blastocoel

Endoderm

Cleavage

Cleavage

Blastula

Ectoderm

Archenteron

Eight-cell stage

Zygote

Gastrulation

Gastrula

Blastocoel

Blastopore

Cross section

of blastula


  • Many animals have at least one larval stage (sexually immature morphology that is different from the adult), which eventually undergoes metamorphosis

  • All animals, and only animals, have Hox genes that regulate the development of body form


Paleozoic Era (542–251 Million Years Ago) – The rise of the animal kingdom

  • The Cambrian explosion (535 to 525 million years ago) marks the earliest fossil appearance of many major groups of living animals

  • There are several hypotheses regarding the cause of the Cambrian explosion

    • New predator-prey relationships

    • A rise in atmospheric oxygen

    • The evolution of the Hox gene complex


Concept 32.3: Animals can be characterized by “body plans”

  • Zoologists sometimes categorize animals according to a body plan, a set of morphological and developmental traits


Symmetry

Radial

  • Animals can be categorized according to the symmetry of their bodies, or lack of it

  • Some animals have radial symmetry, while others show bilateral symmetry.

Bilateral


  • Two-sided symmetry is called bilateral symmetry

  • Bilaterally symmetrical animals have:

    • A dorsal (top) side and a ventral (bottom) side

    • A right and left side

    • Anterior (head) and posterior (tail) ends

    • Cephalization, the development of a head


Tissues

  • Animal body plans also vary according to the organization of the animal’s tissues

  • Tissues are collections of specialized cells isolated from other tissues by membranous layers

  • During development, three germ layersgive rise to the tissues and organs of the animal embryo


  • Ectoderm is the germ layer covering the embryo’s surface

  • Endoderm is the innermost germ layer and lines the developing digestive tube, called the archenteron

  • Diploblastic animals have ectoderm and endoderm

  • Triploblastic animals also have an intervening mesoderm layer; these include all bilaterians


Body Cavities

  • Most triploblastic animals possess a body cavity

  • A true body cavity is called a coelom and is derived from mesoderm

  • Coelomates are animals that possess a true coelom


Fig. 32-8a

Coelom

Body covering

(from ectoderm)

Tissue layer

lining coelom

and suspending

internal organs

(from mesoderm)

Digestive tract

(from endoderm)

(a) Coelomate


  • A pseudocoelom is a body cavity derived from the mesoderm and endoderm

  • Triploblastic animals that possess a pseudocoelom are called pseudocoelomates


Fig. 32-8b

Body covering

(from ectoderm)

Pseudocoelom

Muscle layer

(from

mesoderm)

Digestive tract

(from endoderm)

(b) Pseudocoelomate


  • Triploblastic animals that lack a body cavity are called acoelomates


Fig. 32-8c

Body covering

(from ectoderm)

Tissue-

filled region

(from

mesoderm)

Wall of digestive cavity

(from endoderm)

(c) Acoelomate


Protostome and Deuterostome Development

  • Based on early development, many animals can be categorized as having protostome development or deuterostome development


Cleavage

  • In protostome development, cleavage is spiral and determinate

  • In deuterostome development, cleavage is radial and indeterminate

  • With indeterminate cleavage, each cell in the early stages of cleavage retains the capacity to develop into a complete embryo

  • Indeterminate cleavage makes possible identical twins, and embryonic stem cells


Fig. 32-9

Deuterostome development

(examples: echinoderm,

chordates)

Protostome development

(examples: molluscs,

annelids)

(a) Cleavage

Eight-cell stage

Eight-cell stage

Radial and indeterminate

Spiral and determinate

(b) Coelom formation

Key

Coelom

Ectoderm

Mesoderm

Archenteron

Endoderm

Coelom

Blastopore

Mesoderm

Mesoderm

Blastopore

Solid masses of mesoderm

split and form coelom.

Folds of archenteron

form coelom.

(c) Fate of the blastopore

Anus

Mouth

Digestive tube

Mouth

Anus

Mouth develops from blastopore.

Anus develops from blastopore.


Fig. 32-9a

Deuterostome development

(examples: echinoderms,

chordates)

Protostome development

(examples: molluscs,

annelids)

(a) Cleavage

Eight-cell stage

Eight-cell stage

Spiral and determinate

Radial and indeterminate


Coelom Formation

  • In protostome development, the splitting of solid masses of mesoderm forms the coelom

  • In deuterostome development, the mesoderm buds from the wall of the archenteron to form the coelom


Fig. 32-9b

Protostome development

(examples: molluscs,

annelids)

Deuterostome development

(examples: echinoderms,

chordates)

(b) Coelom formation

Coelom

Key

Ectoderm

Archenteron

Mesoderm

Endoderm

Coelom

Blastopore

Mesoderm

Blastopore

Mesoderm

Solid masses of mesoderm

split and form coelom.

Folds of archenteron

form coelom.


Fate of the Blastopore

  • The blastopore forms during gastrulation and connects the archenteron to the exterior of the gastrula

  • In protostome development, the blastopore becomes the mouth

  • In deuterostome development, the blastopore becomes the anus


Fig. 32-9c

Protostome development

(examples: molluscs,

annelids)

Deuterostome development

(examples: echinoderms,

chordates)

(c) Fate of the blastopore

Anus

Mouth

Key

Ectoderm

Digestive tube

Mesoderm

Endoderm

Anus

Mouth

Mouth develops from blastopore.

Anus develops from blastopore.


Modeling Time

  • Let’s go back to the lab.

    • Take a sheet of paper with you

    • Pick up a direction sheet

    • Get 2 colors of dough


Invertebrates

Those without backbones – make up about 95% of animals


Fig. 33-2

Calcarea

and Silicea

ANCESTRAL

PROTIST

Cnidaria

Lophotrochozoa

Common

ancestor of

all animals

Eumetazoa

Ecdysozoa

Bilateria

Deuterostomia


Sponges

  • Lack true tissues and organs

  • Live in water (both fresh and salt)

  • suspension feeders, capturing food particles suspended in the water that pass through their body

  • Most sponges are hermaphrodites: Each individual functions as both male and female


Fig. 33-4

Food particles

in mucus

Flagellum

Choanocyte

Collar

Choanocyte

Osculum

Azure vase sponge (Callyspongia

plicifera)

Spongocoel

Phagocytosis of

food particles

Amoebocyte

Pore

Spicules

Epidermis

Water

flow

Amoebocytes

Mesohyl


Cnidarians

  • include jellies, corals, and hydras

  • exhibit a relatively simple diploblastic, radial body plan

  • body plan is a sac with a central digestive compartment, the gastrovascular cavity

  • A single opening functions as mouth and anus

  • There are two variations on the body plan: the sessile polyp and motile medusa

  • Carnivores that use tentacles to capture prey

    • Armed with enidocytes – cells that fxn in defense and capturing prey

    • Nematocysts – organelles that eject a stinging thread


Fig. 33-5

Mouth/anus

Tentacle

Polyp

Medusa

Gastrovascular

cavity

Gastrodermis

Mesoglea

Body

stalk

Epidermis

Tentacle

Mouth/anus


Fig. 33-6

Tentacle

Cuticle

of prey

Thread

Nematocyst

“Trigger”

Thread

discharges

Thread

(coiled)

Cnidocyte


Flatworms

  • live in marine, freshwater, and damp terrestrial habitats

  • acoelomates

  • They are flattened dorsoventrally and have a gastrovascular cavity

  • Gas exchange takes place across the surface


Fig. 33-10

Pharynx

Gastrovascular

cavity

Mouth

Eyespots

Ganglia

Ventral nerve cords


Tapeworms

  • Tapeworms are parasites of vertebrates and lack a digestive system

  • Tapeworms absorb nutrients from the host’s intestine

  • Fertilized eggs, produced by sexual reproduction, leave the host’s body in feces


Rotifers

  • Rotifers are tiny animals that inhabit fresh water, the ocean, and damp soil

  • Rotifers have an alimentary canal, a digestive tube with a separate mouth and anus that lies within a fluid-filled pseudocoelom

  • Rotifers reproduce by parthenogenesis, in which females produce offspring from unfertilized eggs

  • Some species are unusual in that they lack males entirely


Mollusca

  • Phylum Mollusca includes snails and slugs, oysters and clams, and octopuses and squids

  • Most molluscs are marine

  • Molluscs are soft-bodied animals, but most are protected by a hard shell

  • All molluscs have a similar body plan with three main parts:

    • Muscular foot

    • Visceral mass

    • Mantle

  • Many molluscs also have a water-filled mantle cavity, and feed using a rasplike radula


Fig. 33-15

Nephridium

Heart

Visceral mass

Coelom

Intestine

Gonads

Mantle

Stomach

Mantle

cavity

Mouth

Shell

Radula

Anus

Gill

Radula

Mouth

Nerve

cords

Esophagus

Foot


Gastropods

  • Most gastropods are marine,

  • Most have a single, spiraled shell

  • Slugs lack a shell or have a reduced shell

  • The most distinctive characteristic of gastropods is torsion, which causes the animal’s anus and mantle to end up above its head


Fig. 33-17

(a) A land snail

(b) A sea slug


Fig. 33-18

Intestine

Mantle

cavity

Stomach

Anus

Mouth


Bivalves

  • Molluscs of class Bivalvia include many species of clams, oysters, mussels, and scallops

  • They have a shell divided into two halves

  • The mantle cavity of a bivalve contains gills that are used for feeding as well as gas exchange


Fig. 33-19


Fig. 33-20

Coelom

Hinge area

Mantle

Gut

Heart

Adductor

muscle

Digestive

gland

Anus

Mouth

Excurrent

siphon

Shell

Water

flow

Palp

Foot

Incurrent

siphon

Mantle

cavity

Gonad

Gill


Cephalopods

Octopus

  • Class Cephalopoda includes squids and octopuses, carnivores with beak-like jaws surrounded by tentacles of their modified foot

  • Cephalopods have a closed circulatory system, well-developed sense organs, and a complex brain

Squid

Chambered

nautilus


Annelids

  • Annelids have bodies composed of a series of fused rings


Concept 33.4: Ecdysozoans are the most species-rich animal group

  • Ecdysozoans are covered by a tough coat called a cuticle

  • The cuticle is shed or molted through a process called ecdysis

  • The two largest phyla are nematodes and arthropods


Nematodes

  • Nematodes, or roundworms, are found in most aquatic habitats, in the soil, in moist tissues of plants, and in body fluids and tissues of animals

  • They have an alimentary canal, but lack a circulatory system

  • Reproduction in nematodes is usually sexual, by internal fertilization

  • Some are parasitic


Arthropods

  • The arthropod body plan consists of a segmented body, hard exoskeleton, and jointed appendages,


Fig. 33-29

Cephalothorax

Abdomen

Antennae

(sensory

reception)

Thorax

Head

Swimming appendages

(one pair located

under each

abdominal segment)

Walking legs

Pincer (defense)

Mouthparts (feeding)


The body of an arthropod is completely covered by the cuticle, an exoskeleton made of layers of protein and the polysaccharide chitin

When an arthropod grows, it molts its exoskeleton

Arthropods have an open circulatory system in which fluid called hemolymph is circulated into the spaces surrounding the tissues and organs


Echinoderms

  • Sea stars and most other echinoderms are slow-moving or sessile marine animals

  • A thin epidermis covers an endoskeleton of hard calcareous plates

  • Echinoderms have a unique water vascular system, a network of hydraulic canals branching into tube feet that function in locomotion, feeding, and gas exchange

  • Males and females are usually separate, and sexual reproduction is external


Fig. 33-39

Stomach

Anus

Spine

Gills

Central disk

Digestive glands

Madreporite

Radial

nerve

Gonads

Ring

canal

Ampulla

Podium

Radial canal

Tube

feet


Fig. 33-40

(a) A sea star (class Asteroidea)

(b) A brittle star (class Ophiuroidea)

(c) A sea urchin (class Echinoidea)

(d) A feather star (class Crinoidea)

(f) A sea daisy (class Concentricycloidea)

(e) A sea cucumber (class Holothuroidea)


Vertebrates

The ones with backbones


Chordata

  • Four key characters of chordates:

    • Notochord

    • Dorsal, hollow nerve cord

    • Pharyngeal slits or clefts

    • Muscular, post-anal tail


Fig. 34-3

Dorsal,

hollow

nerve cord

Muscle

segments

Notochord

Mouth

Anus

Pharyngeal

slits or clefts

Muscular,

post-anal tail


  • The notochord is a longitudinal, flexible rod between the digestive tube and nerve cord

  • It provides skeletal support throughout most of the length of a chordate

  • In most vertebrates, a more complex, jointed skeleton develops, and the adult retains only remnants of the embryonic notochord

  • The nerve cord of a chordate embryo develops from a plate of ectoderm that rolls into a tube dorsal to the notochord

  • The nerve cord develops into the central nervous system: the brain and the spinal cord


  • In most chordates, grooves in the pharynx called pharyngeal clefts develop into slits that open to the outside of the body

  • Functions of pharyngeal slits:

    • Suspension-feeding structures in many invertebrate chordates

    • Gas exchange in vertebrates (except vertebrates with limbs, the tetrapods)

    • Develop into parts of the ear, head, and neck in tetrapods


  • Chordates have a tail posterior to the anus

  • In many species, the tail is greatly reduced during embryonic development

  • The tail contains skeletal elements and muscles

  • It provides propelling force in many aquatic species


Early Chordate Evolution

  • Ancestral chordates may have resembled lancelets

  • Gene expression in lancelets holds clues to the evolution of the vertebrate form


Fig. 34-6

BF1

Otx

Hox3

Nerve cord of lancelet embryo

BF1

Hox3

Otx

Brain of vertebrate embryo

(shown straightened)

Midbrain

Forebrain

Hindbrain


Concept 34.2: Craniates are chordates that have a head

  • The origin of a head opened up a completely new way of feeding for chordates: active predation

  • Craniates share some characteristics: a skull, brain, eyes, and other sensory organs


Derived Characters of Craniates

  • Craniates have two clusters of Hox genes; lancelets and tunicates have only one cluster

  • One feature unique to craniates is the neural crest, a collection of cells near the dorsal margins of the closing neural tube in an embryo

  • Neural crest cells give rise to a variety of structures, including some of the bones and cartilage of the skull


Fig. 34-7

Neural

crest

Neural

tube

Dorsal edges

of neural plate

Migrating neural

crest cells

Notochord


Derived Characters of Vertebrates

  • Vertebrates have the following derived characters:

    • Vertebrae enclosing a spinal cord

    • An elaborate skull

    • Fin rays, in the aquatic forms


Lampreys

  • Lampreys (Petromyzontida) represent the oldest living lineage of vertebrates

  • They are jawless vertebrates inhabiting various marine and freshwater habitats

  • They have cartilaginous segments surrounding the notochord and arching partly over the nerve cord


Chondrichthyans (Sharks, Rays, and Their Relatives)

  • Chondrichthyans (Chondrichthyes) have a skeleton composed primarily of cartilage

  • The cartilaginous skeleton evolved secondarily from an ancestral mineralized skeleton

  • Includes the sharks, rays, and skates


Pelvic fins


Fig. 34-16

Ray-Finned Fishes and Lobe-Fins

Swim

bladder

Dorsal fin

Adipose fin

(characteristic

of trout)

Caudal

fin

Spinal cord

Brain

Nostril

Anal fin

Cut edge

of operculum

Lateral

line

Liver

Gills

Anus

Gonad

Heart

Stomach

Urinary

bladder

Pelvic

fin

Kidney

Intestine

Fishes control their buoyancy with an air sac known as a swim bladder


Fig. 34-17

(a) Yellowfin tuna (Thunnus albacares)

(b) Clownfish (Amphiprion ocellaris)

(d) Fine-spotted moray eel

(Gymnothorax dovii)

(c) Sea horse (Hippocampus      ramulosus)


Tetrapods

  • Tetrapods have some specific adaptations:

    • Four limbs, and feet with digits

    • Ears for detecting airborne sounds


Fig. 34-19

Bones

supporting

gills

Tetrapod

limb

skeleton


Amphibians

  • Amphibian means “both ways of life,” referring to the metamorphosis of an aquatic larva into a terrestrial adult

  • Most amphibians have moist skin that complements the lungs in gas exchange

  • Fertilization is external in most species, and the eggs require a moist environment


Fig. 34-22

(a) Tadpole

(b) During

metamorphosis

(c) Mating adults


Concept 34.6: Amniotes are tetrapods that have a terrestrially adapted egg

  • Amniotes are a group of tetrapods whose living members are the reptiles, including birds, and mammals

  • Have an amniotic egg, which contains membranes that protect the embryo

  • Other terrestrial adaptations include relatively impermeable skin and the ability to use the rib cage to ventilate the lungs


Fig. 34-25

Chorion

Allantois

Yolk sac

Amnion

Embryo

Amniotic

cavity

with

amniotic

fluid

Yolk

(nutrients)

Albumen

Shell


Reptiles

  • Reptiles have scales that create a waterproof barrier

  • They lay shelled eggs on land

  • Most reptiles are ectothermic, absorbing external heat as the main source of body heat

  • Birds are endothermic, capable of keeping the body warm through metabolism


Fig. 34-26


Birds

  • Many characters of birds are adaptations that facilitate flight

  • The major adaptation is wings with keratin feathers

  • Other adaptations include lack of a urinary bladder, females with only one ovary, small gonads, and loss of teeth


Fig. 34-28

Finger 1

(b) Bone structure

Palm

(a) Wing

Finger 2

Finger 3

Forearm

Wrist

Shaft

Shaft

Barb

Vane

Barbule

Hook

(c) Feather structure


Fig. 34-29

Toothed beak

Wing claw

Airfoil wing

with contour

feathers

Long tail with

many vertebrae


Mammals

  • Mammals have

    • Mammary glands, which produce milk

    • Hair

    • A larger brain than other vertebrates of equivalent size

    • Differentiated teeth


three living lineages of mammals emerged: monotremes, marsupials, and eutherians

  • Monotremes are a small group of egg-laying mammals consisting of echidnas and the platypus

  • Marsupials – when the embryo develops within a placenta in the mother’s uterus

  • A marsupial is born very early in its development

  • It completes its embryonic development while nursing in a maternal pouch called a marsupium

  • eutherians have a longer period of pregnancy

  • Young eutherians complete their embryonic development within a uterus, joined to the mother by the placenta


Fig. 34-32


Fig. 34-33

(a) A young brushtail possum

(b) Long-nosed bandicoot


Fig. 34-34

Marsupial

mammals

Marsupial

mammals

Eutherian

mammals

Eutherian

mammals

Plantigale

Deer mouse

Wombat

Woodchuck

Marsupial mole

Mole

Wolverine

Tasmanian devil

Sugar glider

Flying squirrel

Patagonian cavy

Kangaroo


Primates

  • Most primates have hands and feet adapted for grasping

  • Other derived characters of primates:

    • A large brain and short jaws

    • Forward-looking eyes close together on the face, providing depth perception

    • Complex social behavior and parental care

    • A fully opposable thumb (in monkeys and apes)


Fig. 34-36


Fig. 34-38

(a) New World monkey

(b) Old World monkey


Humans

  • A number of characters distinguish humans from other apes:

    • Upright posture and bipedal locomotion

    • Larger brains

    • Language capabilities and symbolic thought

    • The manufacture and use of complex tools

    • Shortened jaw

    • Shorter digestive tract


Fig. 34-40

Paranthropus

robustus

Homo

neanderthalensis

Homo

sapiens

0

Homo

ergaster

?

Paranthropus

boisei

0.5

1.0

Australopithecus

africanus

1.5

2.0

Kenyanthropus

platyops

2.5

Australopithecus

garhi

Australo-

pithecus

anamensis

Homo

erectus

3.0

Millions of years ago

3.5

Homo

habilis

Homo

rudolfensis

4.0

4.5

Australopithecus

afarensis

Ardipithecus

ramidus

5.0

5.5

Orrorin tugenensis

6.0

6.5

Sahelanthropus

tchadensis

7.0


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