BIOL 172 Exam 2

675 and 800 million

Animal diversity arose from a hypothesized ancestor living between ____ and ____ million years ago.

The hypothesized ancestors of animals may have resembled modern ______, protists that are the closest living relatives of animals

choanoflagellates

Cambrian Explosion (535 to 525 million years ago)

The _______ ________ (__________________) marks the earliest fossil appearance of many major groups (phyla) of living animals.

Hox gene

Most animals, and only animals have _____ ___ that regulate many other genes and control the development of body form.

fungi

Animals are much more closely related to ____ than to plants.

Multicellular Eukaryotes, Heterotrophs, Motile for at least a part of the lifespan

The 3 distinguishing Features of an Animal are:

Choanoflagellates

Descended from unicellular colonial protozoans (protists)

parazoans & eumetazoans

Animals are multicellular ______ & ______

~100

_____ phyla appeared during Cambrian Explosion (~530 MYA) and ~34 extant phyla (75% are arthropod species)

Parazoans

Cellular (placozoans, sponges)

Eumetazoans

Tissue (comb jellies, cnidarians), Organ (‘bilaterians”)= most successful plan

Epithelial, Connective, muscular, nervous

The 4 Animal tissue types

Tissues

Groups of differentiated cells that work together to perform specific functions

Epithelial

Thin sheets of lightly joined cells = linings

Connective

Sparse cells in the matrix material = connection and support

Muscular

Contractile cells = produces movement, most abundant and collagen dominates

Nervous

Chemically and electrically excitable cells = receives sensory inputs, integrates/analyzes and sends motor outputs

organs

Tissues are organized into ______

Collagen

The most abundant protein in animals’ bodies

1. Level of body organization

2. body symmetry

3. Fate of first body opening

4. Body cavity type

5. segmentation

6. degree of cephalization

Animal body plans can be grouped by?

sexual

______ reproduction = biggest genetic advantage

asexual

Lots of animals engage in ________ reproduction, including parthenogenesis = faster

multicellular diploids

Animals are __________ _______ (no multicellular haploids!)

cell cleavage

After fertilization (in humans: “conception”)…

1. Zygote undergoes rapid ______ ________→

2. Ball of cells hollows out → blastula

3. Blastula undergoes gastrulation→ gastrula

blastula

After fertilization (in humans: “conception”)…

1. Zygote undergoes rapid cell cleavage →

2. Ball of cells hollows out → _______

3. Blastula undergoes gastrulation→ gastrula

gastrulation → gastrula

After fertilization (in humans: “conception”)…

1. Zygote undergoes rapid cell cleavage →

2. Ball of cells hollows out → blastula

3. Blastula undergoes _________→ ________

gastrula

____ develops 2 or 3 “germ layers” that develop into tissues (via cell migration & differentiation

Ecto

____derm = embryo’s outer layer

Endo

____derm = innermost layer = lining of primitive gut (archenteron)

Meso

____derm = middle layer (Only forms in bilaterians! ….. Protostomes, Deuterostomes)

Protostome

spiral cleavage, coelom forms within the middle tissue germ layer, Initial opening into the gut becomes the mouth

Deuterostome

radial cleavage, coelom forms outpocketing of the middle tissue germ layer, Initial opening into the gut becomes the anus

Deuterostomes, Lophotrochozoa + Ecdysozoa = (Protostomes)

Bilaterians are split into three major groups which are

larvae or juveniles

Animal embryo’s develop into ____ or __________

metamorphosis

Larvae must undergo _____ (1+) to take on adult form

Juvenile

small adult

coelom

Type of _______ (body cavity), WAS the basis for classification of protostome groups — this phased out since its polyphyletic

now u enter spongebob… r u ready

ya i ready lol

Porifera (sponges), placozoa (simplest structure of invertebrates)

Parazoa include:

710 MYA

chemical evidence of first sponges date back __________ ____

choanoflagellates (protisits)

The best candidate ancestor for porifera are _________ (_____ )

filter-feeding

Sponges are all aquatic and have a Porous body wall that allows _____-_____

Endoskeleton

_________ of spongin contain calcareous or siliceous spicules and many are toxic

Motile larvae→ (metamorphosis)→ sessile adults

Sponges (Porifera) engage in both asexual and sexual reproduction and so their _______ larvae → (metamorphosis)→ _____ adults

Spongin spicules

Sponges have calcareous or siliceous = sharp structures that often deliver toxins called…

Aposematic

Warning coloration of a sponge

Collar cells and Amoebocytes

What are the two sponge cell types to know?

NO

Sponges have __ true tissues

feeding currents

Collar cells (choanocytes) create ______ ______ using flagella

intracellular digestion, immune & sexual repro, repar = stem cells

Amoebocytes cruise around and do lost of stuff like: intracellular digestion, immune & sexual repro, repair = stem cells

Amoebacytes

Digest food particles filtered from the water by collar cells (choanocytes)

hermaphrodites

Most sponges are ______

broadcast/released

Sponge sperm are always ____/_____

broad cast spawners or brooders

Sponge eggs may be released or retained by :

“Plaque animals”

Phylum Placazoa are also known as

ONE

ONLY ____ known species of Placazoa is known

motile

Placazoa have no symmetry but are _____ because they walk with cilia and have muscle-like cells

Porifera & Cnidaria

Placazoa DNA evidence suggests its between ______ & _______

The phyla’s in Eumetazoa:

Cnidaria + Ctenophore } ONLY 2 DIPLOBLASTIC PHYLA

Bilateria

Phylum Cnidaria time r u ready?

Phylum cnidaria i am ready 4 u

Phylum Cnidaria

First animals with tissue level of organization

-Epithelial cells have cnidocytes (with nematocysts)

Corals, anemones, jellyfish, box jellyfish, hydrozoans and they are all predatory and/or mutualistic with zooxanthellae

Phylum Cnidaria consist of :

planula larva

Cnidaria can engage in asexual or sexual reproduction and sexual reproduction produces

Sessile Polyp Solitary or Colonial & Motile Medusa

What are the body forms of Cnidaria?

Left

Which is the Sessile Polyp Solitary or colonial body form? Left or Right

Right

Which is the Motile Medusa? Right or Left?

Hydrozoa, Corals, Anemones

Notable Polyps (sessile) include:

jellyfish, box jellyfish

Notable Medusae (motiles) are:

colonial polyps

Cnidarian life cyles may include both polyp and medusa stages… and many have _________ _____

radial

Cnidarians body forms both have ____ symmetry

ectoderm+endoderm

Cnidarians are Diploblastic (___+_____) with mesoglea (not mesoderm) layer in between them

clones of original polyp (asexual reproduction)

Each coral colony =

new colonies

Sexual reproduction of corals make _____ _______

Cnidaria, and Ctenophora

What are the only two DIPLOBLASTIC phyla in Eumetazoa?

8 rows

Phylum Ctenophora , “Comb jellies” have how many rows?

colloblasts

Ctenophora (comb jellies) have tissue level of organization, their epithelial cells have ________

Biradial symmetry

Comb jellies (Ctenophora) have what kind of symmetry?

sexual reproduction

Comb jellies can only copulate through _________ _________ only

anal pores

Comb jellies have a complete gut via a pair of “____ ______”

triploblastic bilateria

The rest of the animal phyla are ________ _______

Bilaterial symmetry, triploblasts, organ level of organization

Bilateria = all the rest of the phyla and they have/are ?

Acoels, Lophotrochozoa (molluscs), Ecdysozoa (arthropods), Deuterostomia (chordata, echinoderms)

The bilateria phyla’s that we’re going to look at is:

Xenacoelomorpha

Another name for “Acoels”?

NOT

Xenacoelomorpha are ____ protostomes or deuterostomes

Xenacoelomorpha

This phylum is the first triploblasts, first with bilateral symmetry + cephalization, and first animals with (some) ORGANS

mouth first

What does Protostome mean?

Lophotrochozoa (molluscs, annelids), Ecdysozoa (nematodes, arthropoda)

What are the two big groups of animals in the Protostomia clade?

Lophotrochozoa

This group is linked by DNA homology and most likely has one of these traits

A horseshoe-shaped feeding structure = lophophore

A unique larva with a wheel of cilia = trochophore

lophophore

A horseshoe-shaped feeding structure in the Lophotrocozoa clade is a?

Trochophore (larva)

A unique larva with a wheel of cilia in the Lophotrocozoa clade is?

Phylum Platyhelminthes

This phylum in the Lophotrochozoa clade are known as “FLATWORMS” and they’re the FIRST PROTOSTOMES and FIRST WITH DIGESTIVE ORGANS