comp unit 1

anatomy

The study of how various parts of an organism are connected and relate to other body parts

morphology

study of anatomy and its significance

functional morphology

The study of the relationship between the anatomical design of a structure and the function(s) it performs

evolutionary morphology

The study of the relationship between the change in anatomical design through time and the processes responsible for this change

function

how a part performs within an organism

How is a structure’s biological role defined?

how the form and function of a biological part perform in an environmental context to contribute to an organisms survival

taxa

group of organisms

taxonomy

scientific discipline of naming organisms

root (know how to label)

the base/beginning of the tree.

It can represent the common ancestor of the taxa shown.

node (know how to label)

 a branching point on the tree.

It represents a point where lineages diverge and can represent a common ancestor of the descendant groups

terminal taxon (know how to label)

The groups located at the tips/endpoints of branches

These frequently represent the organisms/groups being compared, often living groups in the tree being discussed.

clade (know how to label)

an ancestor AND all of its descendants.

also called a: monophyletic group

hierarchy

bilataria —> 1. protostomes 2. deuterostomes—→ 2b. ambulacraria 2c. chordata

evolutionary constraint versus evolutionary trade off and how they relate to evolution of anatomical structures

Evolutionary constraint → something that limits or restricts how an anatomical structure can evolve. If a new structure reduces survival or prevents individuals from reaching reproductive age, it is unlikely to persist.

Evolutionary trade-off → a structure provides a benefit in one area but a cost in another. For example, a structure may increase reproductive success but decrease survival or lifespan.

How they relate to anatomy: Both influence which anatomical structures can successfully evolve and persist in a population.

define convergent evolution

Convergent evolution occurs when two species have a similar, but evolutionarily independent response to a common problem. Convergent evolution results in
analogous traits which have shared functions (and similar structures) in species which are not closely related.

challenges of convergent evolution

Two animals can look extremely similar without being closely related.

That can make reconstructing evolutionary relationships difficult.

kangaroo and jeroas example:Both have characteristics such as:

• long hind limbs

• large feet

• long tails

• similar hopping posture

• superficially similar body shapes

without information about where they came from, it can be assumed:

“These animals must be closely related.”

But appearance alone cannot tell that.

What type of phylogenetic relationship would you expect to see if two organisms are anatomically similar due to analogy? How does this differ from the phylogenetic
relationship you would expect if two organisms are anatomically similar due to homology? (Objective 3)

If two organisms are anatomically similar due to analogy, they do not share a close common ancestor but can share common selection pressures leading to similar functions. If two organisms are anatomically similar due to homology, they share a close common ancestor.

embryology

The branch of biology concerned with embryos and their development to hatching or birth

ontogeny

The changes in an organism from zygote to death

zygote

fertilized egg

morula

A ball of cells formed by cleavage of a zygote

blastula

The hollow, fluid filled ball of cells that forms after the morula

gastrula

The embryo after the cell layers that create the early gut have formed (primitive gut plu three germ layers)

neurula

The embryo after the neural tube has formed (the gut has usually formed before or at the same time)

cranial

towards the head of the body

caudal

towards the tail of the body

dorsal

Directed toward or situated on the back surface, or the surface away from the ground

ventral

Directed toward or situated on the belly surface

parturition

Giving birth to live offspring

oviposition

laying eggs

holoblastic cleavage

Embryonic cleavage where the furrows pass entirely through the zygote

meroblastic cleavage

Embryonic cleavage where only part of the cytoplasm is cleaved

Which type of cleavage occurs in species where eggs have a large amount of yolk?
(Objective 5)

Discoidal cleavage, which is a type of meroblastic cleavage

Define “archenteron,” name the process that forms the archenteron, and explain how it
relates to distinguishing protostomes from deuterostomes (Objective 5)

The archenteron is the early gut.
The archenteron forms during gastrulation.
The archenteron is formed in part from the blastopore and if the blastopore forms into the entrance (mouth) of the archenteron, the organism is a protostome. If the blastopore forms into the exit (anus) of the archenteron, the organism is a deuterostome.

steps of neurulation:

1. The ectoderm on the dorsal surface thickens to form a strip of tissue called the neural plate
2. The neural plate margins raise into neural folds

3. The neural folds meet and merge at midline to form the neural tube
4. The neural tube will develop into the central nervous system

What are the embryonic layers that develop during gastrulation? (Objective 6

Endoderm
• Mesoderm
• Ectoderm

Which organs are formed from ectoderm? (Objective 6

• Epidermis
• The anterior portion of the mouth
• The central nervous system

. Which organs are formed from mesoderm? (Objective 6

• Dermis
• Vertebral column
• Axial and limb muscles
• Heart and blood vessels
• Kidneys and urogenital structures

Which organs are formed from endoderm? (Objective 6)

• Alimentary canal
• Trachea
• Liver and gallbladder
• Pancreas
• Urinary bladder
• Cloaca

What are neural crest cells and what types of structures do they develop into? (Objective 6)

Neural crest cells are ectoderm-derived cells unique to vertebrates that form along the edges of the neural folds during neurulation. They migrate throughout the developing embryo and differentiate into many different structures.

They develop into:

• Craniofacial structures

• Melanocytes

• Odontoblasts → teeth

• Tracheal cartilage

• Laryngeal cartilage

• Ganglia

5. What are neurogenic placodes and what types of structures do they develop into?
(Objective 6

specialized thickened regions of ectoderm in the developing embryo that contribute mainly to the development of sensory structures in vertebrates.

They develop into:

• Lateral line

• Vestibular apparatus → balance

• Lens of the eye

• Olfactory sensory epithelium → smell

Identify the four traits shared by all organisms that are considered Bilateria (Objective 7

Body segmentation
• A cranial-caudal body axis
• Gastrulation
• Bilateral symmetry

7. The embryologic characteristics of protostomes are: (Objective 7)

• Spiral cleavage
• Determinate cleavage
• The blastopore becomes the mouth
• Ectodermal skeleton

The embryologic characteristics of deuterostomes are: (Objective 7)

Radial cleavage
• Indeterminate cleavage
• The blastopore becomes the anus
• Mesodermal skeleton

Are vertebrates protostomes or deuterostomes? (Objective 7)

Vertebrates are deuterostomes

list the unique characteristics of chordates: (Objective 7)

Notochord
Dorsal, hollow nerve cord
Endostyle or a thyroid gland
Postanal tail

What is the functional significance of the notochord? (Objective 7)

The notochord allows for lateral movement of the body while preventing it from
collapsing

How are an endostyle and a thyroid gland similar? (Objective 7)

Both structures develop from the floor of the pharynx
Both structures play a role in iodine metabolism

What is difference between an endostyle and a thyroid gland? (Objective 7)

An endostyle functions in filter feeding while a thyroid gland is an endocrine gland
that produces hormones

Explain why pharyngeal slits are no longer considered to be a unique chordate
characteristic (Objective 8)

Genes and developmental pathways associated with pharyngeal slits are found in non-
chordate organisms.

What types of structures do pharyngeal slits develop/evolve into? (Objective 8)

• Feeding apparatus
• Gills
• Portions of the ear

6. What are the two skeletal anatomical innovations that separate vertebrates from other
chordates? (Objective 9)

the vertebral column and cranium

7. Define the term medial (Objective 9

Directed toward the center of the body

Define the term lateral (Objective 9

Directed toward the extremities of the body

Define “axial skeleton”

The axial skeleton is the portion of the skeleton made up of the cranium and the
vertebral column as well as the ribs and the sternum

List the regions of the vertebral column (Objective 10)

• Cervical
• Thoracic
• Lumbar
• Sacral
• Caudal

label basic parts of vertebra

neural spine and arch, centrum, hemal arch and spine, blood vessel, dorsal hollow nerve cord

identify basic parts of intervertebral disc

Annulus fibrosus = tough outer layer; nucleus pulposus = soft inner center. The spinal cord is positioned dorsal to the disc.

three structural components of cranium

braincase, hyoid apparatus, jaws

What are the three developmental parts of the cranium and their functions? (Objective
12)

. Chondrocranium – supports the brain
2. Dermatocranium – protects the brain
3. Splanchnocranium – supports the jaws, gill arches, and hyoid

List the four tissue types of vertebrates, their roles in the body, and example of each
(Objective 13)

• Epithelial tissues – form boundaries and protect the body – skin or mucosa

• Muscular tissues – exert forces and create movement – cardiac muscle, the iris
of the eye
• Neural tissues – transmit and support the transmission of information –
ganglia, myelin
• Connective tissues – provide support, protection, and strength to the body as
well as connect body structures – ligaments, blood

List the anatomic features besides the cranium and vertebrae that are unique to
vertebrates: (Objective 14)

• A developed head with a three-part brain and complex sense organs
• Complex endocrine organs
• A muscularized gut
• A heart with multiple chambers
• Mineralized tissues
• Gills derived from endoderm

List the organ systems of vertebrates:

• Integumentary
• Skeletal
• Muscular
• Nervous
• Respiratory
• Circulatory
• Digestive
• Excretory
• Reproductive
• Endocrine

59. Define “mineralization” and identify which type of mineralization occurs in the
vertebrate skeleton (Objective 16

Mineralization occurs when inorganic minerals are deposited in the matrix of connective tissues which creates a hard structure. Ossification, deposition of calcium phosphate, occurs in vertebrate skeletons

60. List the ways that cartilage and bone are different (Objective 16)

• The main structural cells of cartilage are chondrocytes, and the main structuralm cells of bone are osteocytes
• The matrix of cartilage contains glycosaminoglycans and the matrix of bone contains calcium phosphate
• Cartilage is avascular and bone is vascular
• Cartilage is less structured, and bone is highly structured
• Cartilage is surrounded by perichondrium and bone is surrounded by periosteum

How does convergent evolution complicate taxonomy?

Convergent evolution can make unrelated or distantly related organisms look anatomically similar because they independently evolve similar traits in response to similar selection pressures. This can make scientists incorrectly assume organisms are closely related based on appearance, even though the similarities are analogous rather than homologous.

What happens/is important at each embryonic stage?

• Zygote → fertilized egg; single cell that begins cleavage

• Morula → solid ball of cells produced by cleavage

• Blastula → hollow ball of cells containing a fluid-filled blastocoel

• Gastrula → primitive gut (archenteron) and 3 germ layers form; body axes begin to be established

• Neurula → neural tube/early central nervous system develops through neurulation

How are the body axes established during embryonic development?

As the embryo develops, its structures allow its orientation to be identified:

• Once the mouth and anus are established → cranial–caudal axis and left–right can be identified.

• During neurulation, the neural plate forms on the dorsal surface → dorsal–ventral axis can be distinguished.

What processes occur between zygote → morula → blastula → gastrula → neurula?

• Zygote → Morula → Blastula = Cleavage

  • Repeated cell divisions

  • Zygote becomes a solid morula, then a hollow blastula

• Blastula → Gastrula = Gastrulation

  • Cells move/reorganize and invaginate

  • Forms the primitive gut (archenteron) and 3 germ layers

• Gastrula → Neurula = Neurulation

  • Ectoderm thickens → neural plate → neural folds → neural tube

  • Begins formation of the central nervous system

label where ectoderm, mesoderm, and endoderm located on an embryo diagram

What structures attach to each region of the vertebral column?

• Cervical → interacts with the cranium

• Thoracic → ribs attach; ribs help connect the vertebral column to the sternum

• Lumbar → no ribs attached

• Sacral → pelvic girdle attaches/interacts

• Caudal → forms the tail

Where are the nerve cord and blood vessel positioned relative to a vertebra?

• Dorsal hollow nerve cord / spinal cord → dorsal to the centrum; passes through the neural arch

• Blood vessel → ventral to the centrum; passes through the hemal arch

What are the vertebrate tissue types + an organ example of each?

• Epithelial tissue → forms boundaries; tightly connected cells

  • Example: skin, mucosa, or serosa

• Neural tissue → transmits and supports information transmission

  • Example: neurons, myelin, or ganglia

• Muscular tissue → exerts force and creates movement through contraction

  • Example: cardiac muscle in the heart or muscle in the iris

• Connective tissue → connects and supports body structures; can also transport substances

  • Example: ligaments, tendons, or blood

How do vertebrate body systems differ from invertebrate chordates?

Vertebrates generally have more complex and specialized body systems than nonvertebrate chordates. The BIG THREE differences to know are:

• Brain: Vertebrates → 3-part brain (forebrain, midbrain, hindbrain); nonvertebrate chordates → simple brain/cerebral vesicle

• Pharynx + gut: Vertebrates → muscularized; nonvertebrate chordates → not muscularized in the same way

• Circulatory system: Vertebrates → multichambered heart; nonvertebrate chordates → no true multichambered heart (may have a pumping region or contractile blood vessels)

Other differences :

• Sensory organs: vertebrates = complex; nonvertebrate chordates = simple

• Endocrine organs: vertebrates = complex; nonvertebrate chordates = simple

• True teeth: can occur in vertebrates; absent in nonvertebrate chordates

• Mineralized tissues: present in vertebrates; absent in nonvertebrate chordates

What are all vertebrate body systems, their functions, and one organ from each?

Integumentary system — protection/barrier; helps with osmoregulation and thermoregulation
→ Skin

Skeletal system — support, protection, and locomotion
→ Vertebral column

Muscular system — produces force and movement
→ Skeletal muscle

Nervous system — transmits and coordinates information
→ Brain

Respiratory system — brings in O₂ and removes CO₂
→ Lungs

Circulatory system — transports oxygen, nutrients, hormones, and immune components
→ Heart

Digestive system — processes food, absorbs nutrients, and eliminates digestive waste
→ Stomach

Excretory/urinary system — eliminates nitrogenous waste and regulates water/body fluids
→ Kidney

Reproductive system — produces gametes and reproductive hormones
→ Ovary or testis

Endocrine system — produces hormones that regulate body processes
→ Endocrine gland

What are the structural differences between cartilage and bone?

Cartilage:

• Cells = chondrocytes

• Matrix rich in GAGs (ex: chondroitin sulfate) + collagen/elastic fibers

• Avascular → no direct blood supply

• No nerves within cartilage

• Less organized structure

• Surrounded by perichondrium

Bone:

• Cells = osteoblasts, osteocytes, osteoclasts

• Matrix mineralized with calcium phosphate

• Vascular → has a blood supply

• Contains nerves

• Highly organized structure

• Surrounded by periosteum