Which chordate feature enabled large animals to develop? A. dorsal tubular nerve cord B. notocho

Which chordate feature enabled large animals to develop? A....

Key Concepts

Notochord

The notochord is a flexible, rod-shaped structure that serves as the primary axial support in the early developmental stage of chordates. It plays a critical role in the patterning of surrounding tissues and organs, acting as a scaffold that enables the formation of a more complex and larger body structure. Its presence is fundamentally linked to the ability of large animals to develop, as it provides the essential support necessary for the growth and maintenance of extensive body plans.

Chordate Body Plan

The chordate body plan includes a set of key anatomical features such as the dorsal tubular nerve cord, pharyngeal pouches, postanal tail, and the notochord. These features work together to support the structure and function of chordates, providing a framework for the development of complex body structures and enabling various physiological processes. The chordate design underpins the diversity and adaptability seen in this group of animals.

Transcript

00:01 Okay, so we are now identifying a chordate feature that allowed large animals to develop.

00:08 So, chordate feature, cordate feature that allowed large animals to develop.

00:24 So that led to large animals.

00:33 Okay, very good.

00:34 So our first option is the dorsal tubular nerve cord.

00:39 We will abbreviate dorsal tubular nerve dtnc.

00:47 Now this is essentially the central nervous system.

00:52 So it acts to send and receive signals as the central nervous system would do in the human body.

01:02 So this cord is essentially the brain and spinal cord.

01:14 Do we see a strong relationship between the dorsal tubular nerve cord and growing in size? it's a little hard to see that at first glance.

01:31 We could see how it would play a role in evolution, maybe being a more intelligent species, but we're going to hold that off for now because we don't see any strong relationship between size there.

01:43 So the other options, we'll just write them down.

01:47 We see note accord, accord.

01:56 We see pharyngeal pouches.

01:59 We will abbreviate those as pp or pharyngeal pouches and postnatal tail.

02:06 We will call p n, or post -anatal tail, sorry, p -n -t.

02:13 Okay, so let's define those really quickly.

02:16 The post -anal tail is the tail portion of a chordate that extends past the anus.

02:28 Okay, so tail past anus...