Assignment 8: Ch 8 Animal-Like protists: The Protozoa-Dr Nath 8

Eukarya

The domain that is unique for having compartmentalized cells is the _______.

All of the above are consequences of early photosynthetic activities

Molecular oxygen began to accumulate in the atmosphere and seas of primitive Earth when cyanobacteria fixed carbon through photosynthesis. Which of the following statements is an accurate description of the consequence of early photosynthetic activities?

stromatolites

Microbial mats found during the Archaean eon resulted in formations called _______.

symbiotic bacterial cells that were incorporated into an early archaeon

Mitochondria and chloroplasts probably originated as _______

All of the above are true of Ediacaran fossils.

Which of the following is true regarding animal fossils of the Ediacaran period?

Opisthokonta

Animals and their closest protist relatives are grouped with other protists in the clade _______

Which one of the following is an accurate description of the “tree of life.”

The tree of life is essentially a bacterial tree in which Archaea and Eukarya are represented by comparatively small branches originating from their common ancestor, which in turn has common ancestry with an ancient bacterial ancestor.

similarities in chromatin structure and gene regulation in Archaea and Eukarya

Evidence that the host cell for the endosymbiotic origin of eukaryons was archaeon include _______

The earliest geological time period for our planet is characterized by cooling of molten earth, condensing water vapor, and the beginning of tectonic activities of newly formed crustal plates. This period of time is called the _______.

Hadean eon

an origin within a reducing atmosphere

Any hypothesis that attempts to explain the spontaneous origin of organic molecules on Earth must account for _______.

800 million years ago

Animal multicellularity arose about _______.

Developmental characters

What kinds of characters are typically used in distinguishing protostomes from deuterostomes?

Molecular oxygen

The atmosphere of earth about 4 bya was probably comprised of all of the following except one. Select the exception.

Protostomia

Which of the following bilaterian clades is characterized by spiral cleavage, schizocoelous coelom formation, a mouth that develops in the region of the blastopore, and trochophore larvae?

Lophotrochozoa

A protostome clade comprised of animals that possess a unique ciliated feeding structure and a top-shaped larva is _______.

the basal phyla

Five animal phyla diverged independently from the animal lineage soon after the first animals evolved. These five phyla are called _______.

transfer of DNA between species

Horizontal gene transfer usually occurs through _______.

4.6 billion years ago

Planet earth formed approximately _______.

Horizontal gene transfer between bacterial and the eukaryon linage may have occurred.

A biologist studies the genetic makeup of a eukaryon. She finds a sequence of bases very similar to a known sequence from a bacterial genome, but the sequence is unknown in any archaeon studied. Which of the following might explain her observations?

Deuterostomia

Which of the following bilaterian clades is characterized by radial cleavage, enterocoelous coelom formation, and an anus that develops in the region of the blastopore?

All of the above describe the importance of membranes to life’s origin.

A critical step in the origin of life must have involved the formation of lipid- or fatty acid-based membranes. Why would membranes play such an important role in the origin of life?

Ecdysozoa

A protostome clade comprised of animals that possess a cuticle that is shed to accommodate growth is _______.

the origin of mitochondria and chloroplasts within eukaryons

Endosymbiosis is the likely explanation for _______.

Both the oxidation of iron in rocks and the presence of oxygen as a result of photosynthesis result in banded iron deposists

Why are banded iron deposits evidence of early (3 billion year old) life?

Both accumulatin of molecular oxygen and availability of diverse niches may help explain the rapid diversification of early life forms.

The rapid diversification of early animal life forms during the Cambrian period may be linked to the _______.