Sfsu bio 240 Exam 3 QUESTIONS AND
CORRECT ANSWERS
Which is a shared, derived character, or synapomorphy of all animals? - CORRECT
ANSWER Gastrulation
What are the characteristics of animals? - CORRECT ANSWER Multicellular
eukaryotes Heterotrophs that acquire or consume food (mostly by ingestion)
Cells lack cell walls and are instead held together by structural proteins like collagen
Nervous tissue and muscle tissues are unique to animals (but not all animals have these cells)
what is Synapomorphy? - CORRECT ANSWER Shared, derived character
What is Symplesiomorphy? - CORRECT ANSWER Shared, primitive character
What are some synapomorhic traits? - CORRECT ANSWER Nerve and muscle tissue -
gastrulation
What are some symplesiomorphic traits? - CORRECT ANSWER multicellular,
heterotrophic, no cell walls
what is a blastula? - CORRECT ANSWER Fertilization of a non-motile haploid egg by
a motile sperm results in a zygote that forms a hollow ball of cells
What are larvae? - CORRECT ANSWER sexually immature and morphologically
distinct from the adult stage.
What do Hox family of genes regulate? - CORRECT ANSWER body development and
provide the layout of the animal body plan
, What do Hox genes do? - CORRECT ANSWER produce proteins that act as
transcription factors to activate or repress expression of other genes
what are choanoflagellates? - CORRECT ANSWER protists that are the closest living
relatives of animals
What are choanocytes? - CORRECT ANSWER individual cells
What are Porifera? - CORRECT ANSWER sponges
What were the drivers of the cambrian explosion? - CORRECT
ANSWER Environmental, Genetic, and Ecological
What were the Environmental drivers of the Cambrian explosion? - CORRECT
ANSWER Warming led to increase in atmospheric oxygen due to plant growth
Supported larger body size and favored triploblasty and larger organisms
Harmful to oxygen-sensitive organisms, aerobic advantage
What were the Genetic drivers of the Cambrian explosion? - CORRECT
ANSWER Evolution of HOX genes led to more complex body forms Common body
plan was unspecialized segmentation
What were the Ecological drivers of the Cambrian explosion? - CORRECT
ANSWER New predator-prey relationships
Hard shells appear
New locomotory modes
When were the first land animals (invertebrates) in Ordovician - CORRECT
ANSWER 460 mya
CORRECT ANSWERS
Which is a shared, derived character, or synapomorphy of all animals? - CORRECT
ANSWER Gastrulation
What are the characteristics of animals? - CORRECT ANSWER Multicellular
eukaryotes Heterotrophs that acquire or consume food (mostly by ingestion)
Cells lack cell walls and are instead held together by structural proteins like collagen
Nervous tissue and muscle tissues are unique to animals (but not all animals have these cells)
what is Synapomorphy? - CORRECT ANSWER Shared, derived character
What is Symplesiomorphy? - CORRECT ANSWER Shared, primitive character
What are some synapomorhic traits? - CORRECT ANSWER Nerve and muscle tissue -
gastrulation
What are some symplesiomorphic traits? - CORRECT ANSWER multicellular,
heterotrophic, no cell walls
what is a blastula? - CORRECT ANSWER Fertilization of a non-motile haploid egg by
a motile sperm results in a zygote that forms a hollow ball of cells
What are larvae? - CORRECT ANSWER sexually immature and morphologically
distinct from the adult stage.
What do Hox family of genes regulate? - CORRECT ANSWER body development and
provide the layout of the animal body plan
, What do Hox genes do? - CORRECT ANSWER produce proteins that act as
transcription factors to activate or repress expression of other genes
what are choanoflagellates? - CORRECT ANSWER protists that are the closest living
relatives of animals
What are choanocytes? - CORRECT ANSWER individual cells
What are Porifera? - CORRECT ANSWER sponges
What were the drivers of the cambrian explosion? - CORRECT
ANSWER Environmental, Genetic, and Ecological
What were the Environmental drivers of the Cambrian explosion? - CORRECT
ANSWER Warming led to increase in atmospheric oxygen due to plant growth
Supported larger body size and favored triploblasty and larger organisms
Harmful to oxygen-sensitive organisms, aerobic advantage
What were the Genetic drivers of the Cambrian explosion? - CORRECT
ANSWER Evolution of HOX genes led to more complex body forms Common body
plan was unspecialized segmentation
What were the Ecological drivers of the Cambrian explosion? - CORRECT
ANSWER New predator-prey relationships
Hard shells appear
New locomotory modes
When were the first land animals (invertebrates) in Ordovician - CORRECT
ANSWER 460 mya
