Earlier arriving species tend to be r-selected species, which are better dispersers, whereas later arriving species are generally K-selected species, which are better competitors.

TLS Online TPP Program

#Id: 1026

#Unit 5. Developmental Biology

Neural plate formation follow the principle of development:  often the signals promoting the specification of one cell type also block the specification of an alternative cell type.

TLS Online TPP Program

#Id: 1027

#Unit 5. Developmental Biology

The cells of the neural plate expresses:  Sox family of transcription factors (Sox1, 2, and 3)

TLS Online TPP Program

#Id: 1028

#Unit 5. Developmental Biology

Sox family of transcription factors

Inhibit the formation of epidermis and neural crest by blocking the transcription and signaling of BMPs

TLS Online TPP Program

#Id: 1029

#Unit 5. Developmental Biology

There are two principal modes of neurulation: 

1. Primary neurulation

2. Secondary neurulation

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#Id: 1030

#Unit 5. Developmental Biology

In primary neurulation, 

cells surrounding the neural plate direct the neural plate cells to proliferate, invaginate into the body, and separate from the surface ectoderm to form an underlying hollow tube.

TLS Online TPP Program

#Id: 1031

#Unit 5. Developmental Biology

In secondary neurulation, 

the neural tube arises from the aggregation of mesenchyme cells into a solid cord that subsequently forms cavities that coalesce to create a hollow tube.