Embryonic Development and Symmetry Flashcards Preview

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Flashcards in Embryonic Development and Symmetry Deck (79)
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1

a zygote is a

multicellular organism

2

A zygote cell is a diploid cell resulting from the union of two what?

two haploid gametes

3

an embryo is a young animal or plant while..

it is still contained within a protective structure

4

the embryoe is NOT exposed to...

the environment

5

what are the two major processes occurring during embryonic development

cleavage and gastrulation

6

what is cleavage

first cell divisions in the embryo

7

what is gastrulation

in-folding, invagination
- the process forms embryonic tissue layers (2-3) from the first layer of cells

8

Gastrula

layers of embryonic cells are formed = germ layers

9

the ectoderm is the

outer skin
- epidermis
- nervous system

10

the endoderm is the

inner skin
- lining of digestive AND respiratory system

11

organisms with 2 germ layers are

diploblastic (with two buds)

12

Mesoderm is the

middle skin
- most internal organs: muscles, skeletal system, heart, stomach

13

Organisms with 3 germ layers are

triploblastic - three buds

14

Archenteron =

old gut
- digestive spaces (gut cavity)

15

blastopore is the

mouth or anus

16

what do tissues enable?

complex body organization

17

what does the gut enable?

extracellular digestion - large food items possible

18

cnidaria are

diplobasltic, blind gut, radial symmetry, multicellular

19

flatwroms are

triploblastic, blind gut, bilaterally symetrical

20

3 types of symmetry

asymmetrical
radially symmetrical
bilaterally symmetrical

21

asymmetrical

no axis divides body into equal halves

22

radially symmetrical

along one axis - as long as one cuts through centre- body can be divided into equal halves from many angles

23

bilaterally symmetrical

-single axis divides body in equal hlaves

24

examples of cnidarians

-jellyfish, sea anemones, corals, hydrozoans

25

how many species of cnidarians are there

11,000

26

cnidarians are...

diploblastic

27

cnidarians have what kind of tissues?

nervous and muscular

28

most life cycles include both of these body forms

polyp - sessile
medusa - motile

29

how do cnidarians obtain energy

- carnivorous
- using cnidocytes to caputre prey, inject prey with venom and stick to prey

30

another way cnidarians obtain energy?

extracellular digestion in gastrovascular cavity
- corals can obtain a large proportion of their energy from symbiotic algae