Essay question

Question 1

Difference in notochord

Answer 1

Is mesoderm derived connective tissues rod extending the dorsal length of the animal

Function - allows muscle to attach to for underlation and correlation movements
Example: hagfish

Question 2

difference in dorsal nerve cord

Answer 2

derived from ectoderm that rolls into a hollow tube during development

Function- basis of the central nervous system

Question 3

difference in vertebrae

Answer 3

structure made of cartilage and bone that replace notochord’s function

function - protection of the dorsal nerve cord
Example: bony fishes

Question 4

Compare and contrast primitive vertebrae and derived vertebrae

Answer 4

Primitive vertebrae- is to served by notochord that allows bending and movement

Derived Vertebrae- notochord role is then replaced by vertebrae made of cartilage or bone for more support and protection of nervous system

Question 5

Define a skull

Answer 5

Endoskeleton connected to the dermato cranium which is composed of dermal bone. It was to protect the brain and give structure

Question 6

Given that most of the Metazoan adults are sessile, how did one lineage of Deuterostomia adults (within Chordata) achieve mobility?

Saying “paedomorphosis” will get you zero points. Must describe the process and give contemporary examples to illustrate paedomorphosis as a viable theory

Answer 6

It occurs through accelerated sexual maturation in the larval stage. Instead of developing into mature adults some have retained their juvenile features like notochord, dorsal nerve cord,post anal tail into adulthood that help w/ mobility. Over time this led to the lineage of motile adults. An example of this is lancelets, they kept notochord and muscles.

Question 7

are the kidneys found in Chordata homologous or analogous? Justify your answer

Answer 7

They are homologous bc they are based on the ancestral archinephros rudimental stage

Question 8

Define archinephros relative to their ancestral conditions

Answer 8

the hypothetical ancestral vertebrate kidney. The closest thing to this is found in larval hagfish.

Question 9

Define pronephros relative to their ancestral conditions

Answer 9

2nd stage kidney that is located in the center of the archinephros

Question 10

Define mesonephros relative to their ancestral conditions

Answer 10

2nd stage kidney that is located in the center of the archinephros

Question 11

Define metanephros relative to their ancestral conditions

Answer 11

Posterior most region of the archinephros

Question 12

Compare and contrast the Nervous and Endocrine Systems

Answer 12

Nervous system- use electricity to communicate, fast communication,

Endocrine system- use chemical messengers to communicate, slow and steady communication

Both are a communication system and sister system because they are derived from the endotherm.

Question 13

Theory on the movement from water onto land. Why move onto land, morphologies that were selected to adapt to life on land (and why)

Answer 13

There was abundant food on the water’s edge and low terrestrial predators.
Air has more oxygen than water, which favored organisms with lungs unlike gills which would have an osmoregulation problem.
Air is much less dense than water so muscular and thicker limbs were preferred to be able to be mobile in land to be able to go further onto land for feeding or survival.

Question 14

Significance of the amniotic egg

Answer 14

Allowed life to move on land by giving an “aquatic” environment to grow out water.
Shell- protective layer
Chorion membrane- aids gas exchange
Amnion- provides cushion and moisture
Allantois- stores nitrogenous waste
yolk - fats for embryo
Albumin- nutrients and cushion for embryo

Question 15

Morphologies of the ancestral mammals and potentially why these were selected

Answer 15

Heterodont dentition that helped with processing different types of food

Longer and slimmer limbs w/ muscles closer to body to improve speed and mobility

Enlarged cerebral region to help with smell

Changes in the middle ear to improve hearing and more rods in the eyes to improve vision.

Question 16

Punctuated Equilibrium Theory vs Gradualism

Answer 16

Punctuated Equilibrium Theory: Proposes that evolution is characterized by long periods of stability (equilibrium) in species, interrupted by short, rapid bursts of significant change.

Gradualism: Suggests that evolution occurs through slow, incremental, and continuous changes over extended periods. It emphasizes steady biological and social development through minor modifications accumulating over time.