Evolution and Development Flashcards
What does it mean if certain animals are all mammals/share common traits?
they share a common ancestor
What do all mammals have in common?
All mammal have this in common – feed their young with milk
What does the word mammal derive from?
The word mammal derives from mammalia which mammals feed their young with.
What does it mean if an animal has a radically different body plan?
The animal is not so closely related as others
the greater the evolutionary distance between organisms…
…the greater the underlying differences in body plan
Define phyla.
the large groupings of different animals.
Define phyla chordate.
phyla of humans
What is the phyla of humans called?
phyla chordate
What is the phyla of starfish?
phyla echinoderm.
What are all phyla part of?
The bilatera
What is radial symmetry?
where any imaginary slice through the animal produces mirror images
What is an example of an animal with radial symmetry?
Cnidaria
What is bilateral symmetry?
when a left and right side and a mirror image is produced only by one cut down the centre of the animal
What are the two types of symmetry?
Bilateral symmetry and radial symmetry
What are animals with bilateral symmetry grouped as?
bilateria
What are animals with radial symmetry grouped as?
Radiata
What has happened between the phylogeny of different animals?
There is a split in the phylogeny of animals
Define the group radiata?
radially symmetrical organisms.
Define the group bilateria.
bilaterally symmetrical
What group of symmetry do Deuterostomia and Protostomia belong to?
Deuterostomia and Protostomia are both Bilateria
What group of symmetry do humans belong to?
Humans are Deuterostomia (bilateria).
Describe the symmetry of bilateria.
Bilateria are bilaterally symmetric along one axis but show differentiation on two axes (dorso-ventral and anterior-posterior)
What happens in step 1 of early embryonic development?
The zygote of an animal undergoes a succession of mitotic cell divisions called cleavage.
What happens in step 2 of early embryonic development?
Only one cleavage stage–the eight-cell embryo–is shown here.