09_-_Introduction_to_the_animals

BUG questions:

Are all animals heterotrophs? Explain.

• Most animals are heterotrophs, meaning they cannot produce their own food.

• Heterotrophs obtain energy and nutrients by consuming other organisms (plants, animals, organic materials).

• This includes the majority of species in the animal kingdom, such as humans.

• Exceptions exist, like certain parasitic species that derive nutrients from hosts without typical feeding mechanisms.

What becomes of the archenteron?

• The archenteron is an embryonic structure that forms during the gastrulation phase of embryonic development.

• It serves as the precursor to the gut, creating the intestinal cavity.

• Ultimately, it develops into the lining of the digestive tract in many animals.

What are two advantages to having strikingly different body forms during development (such as caterpillar and butterfly life stages)? (Hint: why is it advantageous for the sexes to differ or alternative adult morphs).

• Different body forms reduce competition for resources by occupying distinct ecological niches (caterpillars vs. butterflies).

• Specialized forms enhance survival; caterpillars camouflage from predators, while butterflies are adapted for flight and reproduction.

What are four differences between protostomes and deuterostomes? Who can have identical twins?

1. Embryonic Development:

   • Protostomes: The mesoderm splits to form the coelom, and the mouth develops first.

   • Deuterostomes: The coelom forms through outpocketing of the archenteron, and the anus develops first.

2. Cleavage Patterns:

   • Protostomes: Exhibit spiral cleavage (cells divide at oblique angles).

   • Deuterostomes: Exhibit radial cleavage (cells divide parallel or perpendicular to the axis).

3. Fate of the Blastopore:

   • Protostomes: The blastopore becomes the mouth.

   • Deuterostomes: The blastopore becomes the anus.

4. Body Plan Development:

   • Protostomes: Typically have a more diverse body plan with various adaptations; examples include arthropods and mollusks.

   • Deuterostomes: More uniform body plans; examples include chordates and echinoderms.

Identical Twins:

• Only Deuterosomes can produce identical twins.

If all the cells in the body have the same DNA, then why are they different?

Will cloned pet be exactly the same? Explain your response.

Can DNA from an already differentiated cell still drive the development of a whole organism? What is evidence to support your answer?

What are the three germ cell layers? What structures do they produce?

How does number of germ layers influence body symmetry?

What is an adaptive reason for the coelom?

What is a transcription factor?

What are the Hox genes and what is their role in development?

How does a single cell with no differentiation eventually become segmented?

What is the homunculus, and what misconception or misunderstanding about development did this highlight?