The oldest fossil eukaryote that can be resolved taxonomically is of
A) a red alga that lived 1.2 billion years ago.
B) a red alga that lived 635 million years ago.
C) a fungus that lived 2 billion years ago.
D) a fungus that lived 550 million years ago.
E) an Ediacaran that lived 550 million years ago.

a red alga that lived 1.2 billion years ago.

The evolution of complex multicellularity in eukaryotes
A) occurred only once, in the common ancestor of all eukaryotes.
B) occurred only once, in the common ancestor of all multicellular eukaryotes.
C) occurred only once, in the animal lineage.
D) is not documented by the fossil record.
E) occurred independently in several different eukaryotic lineages.

occurred independently in several different eukaryotic lineages.

Plastids that are surrounded by more than two membranes are evidence of
A) evolution from mitochondria.
B) fusion of plastids.
C) origin of the plastids from archaea.
D) secondary endosymbiosis.
E) budding of the plastids from the nuclear envelope.

secondary endosymbiosis.

Biologists think that endosymbiosis gave rise to mitochondria before plastids partly because
A) the products of photosynthesis could not be metabolized without mitochondrial enzymes.
B) all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have
plastids.
C) mitochondrial DNA is less similar to prokaryotic DNA than is plastid DNA.
D) without mitochondrial CO2 production, photosynthesis could not occur.
E) mitochondrial proteins are synthesized on cytosolic ribosomes, whereas plastids utilize their
own ribosomes.

all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have
plastids.

Which group is incorrectly paired with its description?
A) rhizarians—morphologically diverse group that includes amoebas with threadlike
pseudopodia
B) diatoms—important producers in aquatic communities
C) red algae—acquired plastids by secondary endosymbiosis
D) apicomplexans—parasites with intricate life cycles
E) diplomonads—protists with modified mitochondria

red algae—acquired plastids by secondary endosymbiosis

A) The most recent common ancestor of Excavata is older than that of the SAR clade.
B) The most recent common ancestor of the SAR clade is older than that of Unikonta.
C) The most recent common ancestor of red algae and land plants is older than that of nucleariids
and fungi.
D) The most basal (first to diverge) eukaryotic supergroup cannot be determined.
E) Excavata is the most basal eukaryotic supergroup.

The most basal (first to diverge) eukaryotic supergroup cannot be determined.