Animal Diversity I

Front 1

How many animal species are there?

Back 1

1.3 million species described, but 10-20 or 100-200 million total

Front 2

How do animals differ from plants?

Back 2

1. Animals differ from plants and fungi in their mode of nutrition.

Plants are autotrophic and derive nutrition through photosynthesis. Fungi release exoenzymes that digest food outside their bodies.

Animals eat other living organisms or nonliving organic materials use enzymes to digest food after they’ve ingested it.


2. Animals are multicellular (like plants and fungi) but they lack cell walls for support.

Instead, they’re held together by structural proteins like collagen.

3. Animals have specialized cell types organized in into epithelial tissues.

4. Animals have two specialized cell types not seen in other multicelluar organisms, muscles & nerve cells.

5. Most animals reproduce sexually and the diploid stage dominates the life cycle (there is no haploid multicellular gametophyte).

6. In most species, a small motile sperm fertilizes a large nonmotile egg, producing a zygote.

Front 3

Heterotrophs

Back 3

Animals are heterotrophs, and are unable to synthesize organic, carbon based compounds independently from the inorganic environment's sources (e.g. Animalia, unlike Plantae, cannot photosynthesize) and therefore must obtain their nutrition from another heterotroph or an autotroph.

Front 4

Cleavage

Back 4

A succession of mitotic divisions
without cell growth between divisions

Front 5

Blastula

Back 5

Multicellar stage resulting from many cleavages. The blastula of many animals is a hollow ball of cells.

Front 6

Gastrulation

Back 6

Following blastula stage, one end of the embryo folds in, expands, and eventually fills the blastocoel.

Front 7

Blastocoel

Back 7

Inside of a hollow blastula

Front 8

Archenteron

Back 8

The hollow center formed by gastrulation, the archenteron opens to the outside through the blastopore

Front 9

Blastopore

Back 9

Opening of the archenteron, forms the mouth or the anus when developing into an animal.

Front 10

Endoderm

Back 10

Eventually forms the lining of the digestive tract, lines inside of archenteron. Ectoderm lines outside of cleaved cell.

Front 11

Spiral Cleavage

Back 11

Planes of cell division (cleavage) are diagonal to the vertical axis of the embryo

Front 12

Radial Cleavage

Back 12

Planes of cell division (cleavage) line up

Front 13

Coelom

Back 13

The usually epithelial-lined space between the body wall and the digestive tract

Front 14

Protostomal Development

Back 14

Spiral and determinate, schizocoelous, mouth from
blastopore

Front 15

Deuterostomal Development

Back 15

Radial and indeterminate, enterocoelous, anus from blastopore

Front 16

Schizocoelous

Back 16

Solid masses of mesoderm split and form coelom- Protosomes

Front 17

Enterocoelous

Back 17

Folds of archenteron form coelom- Deuterostomes

Front 18

Acoelomates

Back 18

Lack a body cavity between
the digestive cavity and the
outer body wall

Front 19

Pseudocoelomates

Back 19

Have a body cavity only
partially lined (by tissue
derived from mesoderm)

Front 20

Coelomates

Back 20

Have a body cavity
completely lined (by tissue
derived from mesoderm)

Front 21

Diploblastic

Back 21

Animals have only two layers: ectoderm and endoderm

Front 22

Triploblastic

Back 22

Animals have three layers: ectoderm, endoderm and mesoderm

Front 23

Asymmetrical

Back 23

Have no real symmetry, like sponges

Front 24

Radial symmetry

Back 24

They have a top and bottom, but no front or rear, and no left and right sides, like sea anemones

Front 25

Bilateral symmetry

Back 25

They have a top and bottom, a
front and rear, and left and right
sides, like humans

Front 26

Animals in general

Back 26

•heterotrophs
•multi-cellular
•specialized tissues (including muscles and nerve cells)
•sexual reproduction with a dominant diploid stage
•small motile sperm and large non-motile eggs

Front 27

What is sister to Fungi + Animalia + Choanoflagellates?

Back 27

Amoebozoa, common ancestor like an amoeba?

Front 28

Common ancestor of Animalia and Choanoflagellates?

Back 28

Probably resembled modern Choanoflagellates (that lived 1.2 BYA to 800 MYA)

cause Choanoflagellates resemble a type
of cell found in basal animals (like sponges)

Front 29

Basal

Back 29

Found at the base of the evolutionary tree

Front 30

Choanocytes

Back 30

In sponges, the colonial protists that trap food particles and feed the sponge, evidence of choanoflagellates as a common ancestor to animals

Generate water current into the
sponge and trap and ingest food particles

Front 31

Porifera

Back 31

phylum of sponges

Front 32

Metazoa

Back 32

35 phyla within, base of evolutionary tree for animals, cellular grade complexity, no gut, e.g. sponges

Front 33

“cellular grade” of complexity

Back 33

different cells in individuals perform different functions, but cells don't work together

Front 34

Eumetazoa

Back 34

second branch up the tree after Metazoa, tissue level complexity, have guts

All animals aside from sponges belong to this clade.

•tissues: “tissue grade” of
complexity
•diploblastic or triploblastic
•radially or bilaterally symmetric

Front 35

Tissues grade complexity

Back 35

groups of similar cells working together perform a specific function

Front 36

Cell types in sponges

Back 36

Most basal metazoans, choanocytes, porocytes, epidermis, mesohyl, amoebocytes,

Front 37

Porocytes

Back 37

Water enters the sponge through porocyte cells that span the body wall

Front 38

Epidermis

Back 38

The body is covered by tightly-packed epidermal cells

Front 39

Mesohyl

Back 39

The body consists of two layers of cells, separated by a gelatinous layer….the mesohyl

Front 40

Amoebocytes

Back 40

Amoebocytes are found throughout the mesohyl take up food from the water & from choanocytes, digest it and carry it to other cells manufacture tough skeletal fibers within the mesohyl

Front 41

Spicules

Back 41

Tough skeletal fibers within the mesohyl which provide support in some sponge species. They are
made from calcium carbonate or silica.

Front 42

Spongin

Back 42

In other sponge species, support is provided by flexible fibers of a collagen protein

Front 43

Suspension feeders

Back 43

Water exits the spongocoel through the osculum, there is a constant flow of water into and out of the sponge and they feed on suspended particles in the water

Front 44

Reproduction in sponges (phylum Porifera)

Back 44

Most are hermaphrodites
individuals produce both sperm AND eggs and almost all are sequentially hermaphroditic
first one sex, then the other.

Saltwater sponges: Gametes are produced by the choanocytes and/or amoebocytes. Sperm released into water, eggs remain in mesohyl. Eggs are fertilized in mesohyl. Flagellated larvae disperse from parent and settle on substrate to make new sponges.

Freshwater sponges: Sponges can also reproduce asexually by producing specialized cells called gemmules.

Front 45

Gemmules

Back 45

Cells produced by asexually reproducing sponges. Released into the water and drift around until they release amoeboctyes that differentiate into a newly
developing sponge

Front 46

Radially symmetric Eumetazoans

Back 46

Paraphylatic- the Cnidarians & the Ctenphorans

Front 47

Cnidarians' body plans

Back 47

Corals, jellies, anemones, hydras

Two body plans:
•sessile polyp (cylindrical forms that adhere to the substrate)
•mobile medusa (flattened free swimming form with mouth facing down)

Some alternation of generation include both forms.

Others don't. Corals and sea anemones
do not have medusae. Open-ocean jellyfish tend to skip the polyp stage

Front 48

Characteristics of Cnidarians

Back 48

•have radial symmetry
•and are diploblastic (only have ectoderm & endoderm)
•they also have a single opening that serves as a mouth and an anus!
•and they have stinging cells!!! (called cnidocytes)

Front 49

Cnidocytes

Back 49

Stinging cells in Cnidarians

Front 50

Class Hydrozoa

Back 50

Portuguese Man O War, Hydras, Obelias, some Corals- Most marine, a few fresh water, both polyp and medusa stages in most species, polyp stage in colonial species

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Class Scyphozoa

Back 51

Jellies- All marine, polyp stage reduced, free swimming medusas up to 2m in diameter

Front 52

Cubozoa

Back 52

Box jellies, sea wasps- all marine, box shaped, some TOXIC

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Anthozoa

Back 53

Sea anemones, most coral, sea fans- all marine, medusa stage completely absent, sessile, many colonial

Most corals have a symbiotic relationship with photosynthetic protists

Front 54

Ctenophorans

Back 54

"comb jellies"

•~ 100 species
•COLLOBLASTS: adhesive patches on tentacles for catching prey
•Eight rows of comb-like plates
for swimming
•Complete gut—mouth and anus

Front 55

Colloblasts

Back 55

Adhesive patches on tentacles for catching prey