Ryk Animalia Flashcards
(19 cards)
Q: What is a phylogenetic tree?
A: A phylogenetic tree is a timeline showing how organisms have appeared with different physical characteristics appearing along the way [1]. It shows common ancestors
Q: What is asymmetry in animals?
Asymmetry means the organism cannot be divided in any way to form two mirror images [3]. Asymmetrical organisms have no cephalization [3]. The only asymmetrical organism is Porifera or Sponges
Q: What is radial symmetry?
Radial symmetry means that no matter which way you cut the individual through the center you will always have the same half on either side
Q: What is bilateral symmetry?
A: Bilateral symmetry is where if you cut an organism down the center of their bodies from the anterior (front) end to the posterior (back) end they will make two identical copies or mirrored sides
Q: What is cephalization?
Cephalization essentially means that at the anterior end (where the head is) you will find a cluster of sensory cells
Q: What are tissue layers?
A: Animals develop from a single cell (zygote) that divides to form an embryo [7]. The cells organize themselves into tissue layers which leads to the organization of organs
Q: What is a diploblast?
A: A diploblast contains two germ layers: the ectoderm and the endoderm These are separated by a non-cellular jelly-like layer called the mesoglea [8]. Diploblastic animals have a tissue level of organization (no organs
Q: What is a triploblast?
A: A triploblast is made out of three tissue layers: the endoderm and the mesoderm
Q: What is a coelom?
A: A coelom is an internal fluid-filled space in the middle of the mesoderm of triploblastic animals [11]. It is a body cavity where specialized organs can be held
Q: What is an acoelomate?
A: An acoelomate has no coelom or space in the mesoderm [11]. An example is a flatworm (Platyhelminthes) [
Q: What is a pseudocoelomate?
A: A pseudocoelomate has a coelom present but it is not considered a “true” coelom because it is not double-layered by the mesoderm [11]. It is a cavity where organs can be placed
Q: What is a coelomate?
A: A coelomate has a true coelom or cavity within the mesoderm [11]. This is where the majority of animals lie [12]. The mesoderm sits like an outer and inner ring providing space for organs that are kept separate and function independently [12]. Examples include Annelida
Q: What are the advantages of having a coelom?
A: The advantages of having a coelom include allowing for the development of complex organs that can grow bigger and be more specialized It allows organs to grow independently of one another [17]. A coelom also allows for more complex digestion
Q: Describe the characteristics of Porifera (sponges).
A: Porifera are the simplest and oldest animals [17]. They are sessile (do not move) They are two cell layers thick
Q: Describe the characteristics of Cnidaria.
A: Cnidaria include jellyfish, corals
Q: Describe the characteristics of Platyhelminthes (flatworms).
A: Platyhelminthes are mostly flatworms that live in aquatic environments [21]. Some are free-living while others are parasites (like tapeworms) [22]. They have a single gut
Q: Describe the characteristics of Annelida (segmented worms).
A: Annelida include earthworms and leeches [22]. They have hydrostatic skeletons and need moisture to live often breathing through their skin [22]. They are triploblastic [14
Q: Describe the characteristics of Arthropoda.
A: Arthropoda include insects, spiders
Q: Describe the characteristics of Chordata.
Chordata include birds, fish
