what is an animal?

Question 1

important characteristics animals share

Answer 1

they are all multicellular with specialized cells

they get energy for life by eating other organisms

they can move and sense their environment

generation of sperm and egg are differrent size

typically; gastrulation process takes place

Question 2

importance of epithetial cell

Answer 2

• are brickshapes/columned shaped fluid and flexible cells with specialized proteins
• control chemica composisionts of liquids
• allow animals to create fluid filled spaces for body support/wate concentration
• fluidfilled spaces; allow increase in size and energy efficent locomotion
• allow for precise folding of movements to occur

Question 3

explain gasturlation

Answer 3

a ball of epithlial cells (called the blasutla) is formed by a series of cell divisions from the single, fertilize egg cell

this ball indends itself/falls inwarrds into a groove to move cells inward; forms the gut

indentented ball is called the gastula

Question 4

rule of phylogency about groupign

Answer 4

‘natural groups’ must have a shared evolutionary ancestor (clade)

Question 5

what is the animal calde

Answer 5

metazoa

Question 6

closest relative to animals

Answer 6

choanoflagellates; have circular tetncales adn flagellum

Question 7

similarities between choanoflagellate and sponge?

Answer 7

they feed similariy using flagellum to create water currents

Question 8

opisthokonta

Answer 8

animals, fungi and choanoflagatlletes

• multicellularity evolved twice;
  1. gavve rise to animals
  2. gave rise to fungi

Question 9

why should multicellularity evolve?

Answer 9

• having many cells allows an organism to grow larger to avoid predators of other sells
• lyn margulis suggested; it allows for the division of labour (some cells grow, others carry on feeding)
• wolpert-kerszberg: self-cannibalism as initial driver for evolution of mulitcelularuty; cells share nutrients to allow for surival; hence eat selves