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Flashcards in Final Exam Deck (37):
1

Metazoa arose from a flagellated, colonial ancestor supports what hypothesis

The origin of metazoas

2

How many germ layers do poriferan embryos possess

none

3

A shared derived trait is called a

synapormorphy

4

What is a convergent (analogous) traint

a shared trait in unrelated organism

5

polymorphism

when an organism or species has several stages or forms

6

What is the life cycle of Cnidaria

Zygote > Planula larvae > Polyp (scyphistoma) > ephyra > medusa>>>>

7

What are maternal effect genes

they code for morphogens invested in an egg prior to fertilization

8

What principle states that no two species can occupy the same niche at the same time

Competitive Exclusion

9

Interspecific Competition

a form competition in which individuals of different species compete for the same resource.

10

Succession

The process of changing species inhabitants over time

11

the degree to which a taxon is more numerous than its competitors in an ecological community

Ecological dominance

12

Diploblastic organisms have which germ layers

endoderm and ectoderm

13

Triploblastic organisms have which germ layers

endoderm, ectoderm, and mesoderm

14

True jellyfish belong to the class

Scyphozoa

15

Cell fate

programmed identify of cells

16

first cell divisions where zygotic contents partition into smaller cells

Cleavage

17

the biological process of an organism that causes it to form its shape

morphogenesis

18

morphogens

a gradient of gene products that guide development

19

Hydrozoa medusas reproduce _____

sexually

20

a sponge feeds by

generating a current with collar cells; food is absorbed by collar cells

21

a unusual feature of cnidarian neurons is

the capability to transmit nerve impulses in both directions across a neuron

22

Nematocysts are

stinging cells; produced only by cnidarians; cnidocytes

23

Skeletal elements of poriferans (spicules) are produced by cells called

Sclerocytes

24

Calcareous or siliceous elements produced by sclerocytes in poriferans

spicules

25

spongin

modified collagen produced by spongocytes

26

(T or F) Ctneophores possess a single anus, whereas cnidarians possess two anal pores?

(False) Cnidarians do not have complete gut; no anus

27

(T or F) Cnidarians produce contractile cells from ectoderm?

True

28

(T or F) Cnidarians posses biradial symmetry, but ctenophores have a simpler, radial symmetry?

(False) Cnidarians have a radial symmetry and ctenophores have a biradial symmetry

29

The velum is a characteristic of the ____ subclass ____ and provides what function

cnidarian; hydrozoa ; improves movement

30

(T or F) Comb jellies have complete guts

True

31

(T or F) hydrozoans have complete guts

(False) Cnidarians have a gastrovascular cavity

32

(T or F) sponges have a complete gut

(False) they don't contain any guts

33

At which stage do we begin to see development of the mesoderm germ layer

gastrulation

34

cleavage of a zygote produces cells called

blastomeres

35

name four of the 7 larvae forms of Poriferans

Cinctoblastula, calciblastula, amphiblastula, trachimella

36

What are homeotic genes?

they cause the development of specific structures in plants and animals.

37

What are the unique characteristics to animals

1) Blastula
2) Cell adhesion molecules including fibronectins and cadherins
3) Cell junctions
4) Extracellular Matrix