LE1 Compana Lab

Comparative Anatomy

the study of similarities and differences in the anatomy of different speciesto understand evolutionary relationships.

backbones and limbs

identical structure in embryonic origin

Notochord, Dorsal Hollow Nerve Cord, Pharyngeal Slits, Post-Anal Tail, Endostyle

Notable Features of Chordates

SUBPHYLUM CEPHALOCHORDATA

notochord extends into the head, filter-feeding using pharyngeal slits, and has a fish-like body, retains the notochord throughout life, lacks backbone

SUBPHYLUM UROCHORDATA/TUNICATA

marine animals with a tunic, filter feeding through a pharyngeal basket, notochord and nerve cord are present only in the larval stage, lacks backbone

SUBPHYLUM VERTEBRATA

notochord replaced by a vertebral column, well-developed head and brain, complex sensory organs, and a closed circulatory system, exhibits a backbone and complex body systems

Gill Arches for Bony Fish, Jaw and Inner Ear for Terrestrial Animals

What will the pharyngeal pouches be when the organism matures?

thyroid gland

What will the Endostyle be when the organism matures?

Central nervous system

What will the dorsal tubular nerve cord be when the organism matures?

vertebrae/backbone

What will the notochord be when the organism matures?

Tails, coccyx in humans

What will the postanal tail be when the organism matures?

Mouth

First structure that develops for protosomes

Anus

First structure that develops for deuterosomes

Vertebrates

Animals with a backbone or spinal column.

Agnatha

• do not have true jaws like other fish

• have a circular, toothed mouth

• have a cartilaginous skeleton rather than made of bone

• lack scales on their bodies

• have long, eel-like bodies

• often parasitic

Pacific Lamprey, Entosphenus tridentatus

Give the common and scientific name of this animal.

Cartilage

Skeleton of Chondrichthyes

Chondrichthyes

Type of fish that is covered with placoid scales

False

True or False:

Chondrichthyes have a swim bladder.

Internal Fertilization

What type of fertilization does Chondrichthyes have?

Oviviparous or viviparous

What type of reproduction does chondrichthyes have?

Heterocercal

Tail shape of chondrichthyes

Bone

Skeleton of Osteichthyes

Osteichthyes

Its skin is soft, covered with cycloid or ctenoid scales.

True

True or False:

Osteichthyes have swim bladders

Buoyancy

What is the purpose of a swim bladder in Osteichthyes?

True

True or False:

Chondrichthyes have exposed gill slits

Operculum

What covers the gills of Osteichthyes?

Mostly external, some internal

How does Osteichthyes fertilize?

Oviparous

How does Osteichthyes reproduce?

Homocercal

Tail shape of osteichthyes

Mammals and Birds

Which groups of vertebrates are endotherms?

Fishes, Amphibians, Reptiles

Which groups of vertebrates are ectotherms?

Amphibians, Reptiles, Mammals, Birds

Which groups of vertebrates are tetrapods?

Amphibians

• characterized by their ability to exploit both aquatic and terrestrial habitats
• lays their egg on water
• typically have a thin, moist skin and rely heavily on cutaneous respiration

Aposematism

Term for bright coloration of organisms to serve warning to predators

Batrachotoxin

One powerful chemical that the specialized glands of some amphibians secrete.

Reptiles

• external covering of epidermal scales

• lay their eggs on land

False

True or False:

Snakes aren’t really tetrapods because they do not have legs.

Birds

• have feathers that provide insulation, aid in flight

• lays hard-shelled eggs

• have wings

• have beaks or bills

• have highly modified scales

• lightweight skeletons with hollow bone

Mammals

• feed their young with milk produced by the mother – “mammary glands”

• skin of many mammals is covered with sweat glands

• covered with hair or fur (some have scales)

Mammary Glands

Defining structure that makes mammals, mammals.

True

True or False:

Whales and dolphins have hair

Tubercles

Bumps found on a humpback whales’ head, mouth, and flipper.

Evolution

the change in the characteristics of a species over several generations and relies on the process of natural selection

Natural Selection

Process where individuals having more useful traits survive better and produce more progeny than individuals with less-favorable traits

Divergent Evolution

Occurs when groups from the same common ancestor split into two groups by a geographic barrier (for instance, a body of water or a migration to a new area), causing each group to develop different traits.

Convergent Evolution

Occurs when organisms that aren't closely related evolve similar traits as they both adapt to similar environments.

Coevolution

Occurs when two or more species reciprocally affect each other's evolution through the process of natural selection

Phylogeny

study of the relationship between all the organisms on Earth that have descended from a common ancestor

Taxonomy

Branch of science of naming, describing, and classifying organisms

Taxon

any particular group of organisms is called a ____

Carolus Linnaeus

Known as the father of taxonomy because of his adoptation of Binomial Nomenclature.

Binomial Nomenclature

A system that uses a unique, two-part scientific name derived from Latin or Greek to each kind of organism

Monophyletic

includes the most recent common ancestor of a group of organisms, and all of its descendants

Polyphyletic

does not include the common ancestor of all members of the taxon

Paraphyletic

includes the most recent common ancestor of a group of organisms, but NOT all of its descendants

Monophyletic

What type of taxon is this?

Polyphyletic

What type of taxon is this?

Paraphyletic

What type of taxon is this?

Liolaemus messii

Give me the scientific name of this species.

Cirrhilabrus wakanda

Give me the scientific name of this species.

Trimeresurus salazar

Give me the scientific name of this species.

Thanos simonattoi

Give me the scientific name of this species.

Boops boops

Give me the scientific name of this species.

Homologous Structures

Term for structures that have similar physical features in organisms that share a common ancestor, but the features serve completely different functions

Analogous structures

These are features of different species that are similar in function but not necessarily in structure and do not derive from a common ancestral feature

Lancelet (Amphioxus)

Wh▪ small, elongated, "fish-like" benthic filter-feeding chordates in the subphylum Cephalochordata ▪ lacks a true vertebral column, but has a notochord ▪ displays primitive features of chordates, including a dorsal nerve cord ▪ lacks well-developed sensory organs, brain, and skullat species is this?

Lancelet (Amphioxus)

▪ small, elongated, "fish-like" benthic filter-feeding chordates in the subphylum Cephalochordata

▪ lacks a true vertebral column, but has a notochord

▪ displays primitive features of chordates, including a dorsal nerve cord

▪ lacks well-developed sensory organs, brain, and skull

Subphylum Cephalochordata

What type of chordate is this species?

Subphylum Cephalochordata

What type of chordate is this species?

Ammocoetes (Lamprey Larva)

▪ elongated, eel-like during larval stage
▪ possesses a notochord and rudimentary vertebral elements

▪ lacks paired fins and jaws, with a sucker-like oral disk

▪ undergoes filter-feeding through gill slits

Spiracle

Small respiratory opening behind the eyes, aids in water intake for respiration when the mouth is closed

Lateral Line

Sensory organ running along the sides, detects vibrations and movements in water

Claspers

Paired reproductive organs found in males, used to transfer sperm during mating

False

True or False:

Claspers in sharks and rays can be found in male and female species.

Shark, Selachimorpha

What is the common name and scientific name of this species?

Ampullae of Lorenzini

What do you call the small black pores that are also specialized electroreceptors for detecting prey?

Stingray

▪ flattened, disc-shaped body adapted for bottom-dwelling

▪ ventral gill slits located on the underside for respiration

▪ barbed tail spine often equipped with venom for defense

▪ pectoral fins fused with the head, forming wing-like structures for swimming

Stingray, Myliobatoidei

What is the common name and scientific name of this species?

Placoid Scales

▪ tough, tooth-like scales found in cartilaginous fishes like sharks

▪ reduces drag and increases swimming efficiency by smoothing water flow
▪ provides protection from predators and environmental abrasions

Dentine and Enamel

What is the composition of placoid scales?

True

True or False:
Placoid scales does not overlap like other fish scales.

Milkfish, Chanos chanos

What is the common and scientific name of this species?

Milkfish

This species has:

▪ slender, streamlined body adapted for fast swimming

▪ forked caudal fin for efficient propulsion

▪ cycloid scales, smooth and thin, typical of teleosts

Cycloid scale

What type of scale is this?

Cycloid Scale

▪ thin, round, smooth-edged scales common in bony fish

▪ growth rings visible, indicating age and growth rate

▪found in salmon, carp, goldfish, milkfish

Collagen and Calcium Salts

What is the composition of cycloid scale?

False

True or False:

Cycloid scales have enamel and dentine like placoid and ganoid scales.

Ctenoid Scales

What type of scale is in the picture?

Ctenoid Scale

▪ thin, rough-edged scales found in advanced bony fish

▪ growth rings visible, indicating fish age and development

▪ found in perch, bass, trout, sunfish

Collagen and Calcium Salts

What is the composition of Ctenoid scale?

Cteni

small tooth-like projections along the posterior edge in a ctenoid scale

Ganoid Scale

What type of scale is this?

Ganoid Scale

▪ found in primitive fish with a more ancient lineage

▪ found in sturgeon and gars
▪ thick, bony, and armor-like scales with a shiny enamel-like surface

Dentine and a Layer of Enamel

Composition of Ganoid Scales

Dermal Scales

What type of scales does a fish have?

Epidermal Scales

What type of scales does a reptile have?

Feathers (Modified Epidermal Scales)

What type of scales does a bird have?

Mostly epidermal scales, sometimes keratin scales

What type of scales does a mammal have?