Exam 3

general bio II villanova

Animals pt 1

update didnt attend

Neoproterozoic Era

1 bya - 541 mya
Most severe glaciation period, ice sheets reached equator

When did animals first appear?

700 mya

Monophyletic

ALL descendants came from one common ancestor

Common ancestor of animals

choanoflagellates

When were animal fossils found

560 mya

Paleozoic Era

541-252 mya
Cambrian explosion
Permian mass extinction

Cambrian Explosion

535-525 mya
1/2 of all extant animal phyla have oldest fossils found here
Most bilaterians appear here
Animals moved from sea -\> land

What caused the Cambrian explosion?

Atmospheric changes
Predator-prey relationships
Changes in development

Permian Mass Extinction

250 mya
96% all marine species extinct
70% terrestrial vertebrate species extinct

What likely caused the Permian extinction?

Impact event, increased volcanoes, methane from sea floor
Sea level changes, anoxic and arid

Mesozoic Era

252-266 mya
Age of reptiles
Lots of environmental activity (climate, tectonics, evolution)
Diversification

Cretaceous Mass Extinction

65 mya
Asteroid hits -\> causes global cooling
75% all species lost

Cenozoic Era

66 mya - present
Age of Mammals
Current extinction (habitat loss, pollution/toxins, overexploitation)

Animals pt 2

divider

How are animals characterized/organized

Tissues
Symmetry
Body Cavities
Development I
Development II

Parazoa

no true tissues (sponges)

Eumetazoa

animals with true tissues

Ectoderm

the outer germ layer that develops into skin, hair, teeth

Endoderm

the inner germ layer that develops into the digestive tract and respiratory systems

Mesoderm

the middle germ layer that develops into muscles, skeletal structures, and the circulatory system

Diploblastic

Having two germ layers.

Triploblastic

Having three germ layers.

The two phyla that do not have mesoderm (diploblastic)

Ctenophores (comb jellies)
Cnidarians (corals, jellies, hydras)

True or false: sponges have radial symmetry

False, sponges have no symmetry

Radial symmetry

Symmetry about a central axis
Cnidarians, ctenophores

Bilateral symetry

One line that divides it into haves that are mirror images
Most bilateral organisms have cephalization

cephalization

concentration of sense organs and nerve cells at the front of an animal's body

Acoelomate

No fluid-filled/air-filled body cavity (solid)
Flatworms, sponges, cnidarians, ctenophores

Pseudocoelomate

Fluid-filled/air-filled body cavity lined with mesoderm and endoderm

Coelomate

Body cavity completely lined with mesoderm
Most animals

What advantages do coelomates have?

organs grow/move independently
internal fluid transport
cushioning for organs/structures

Development I separates

protostomes from deuterostomes

blastopore

the opening of the central cavity of an embryo in the early stage of development

Protostomes

Animals with a mouth that develop from blastopore

Deuterostomes

Animals with an anus that develops from the blastopore

Advantage of Deuterostomes

developmental flexibility

Development II creates

Protostome divisions: Ecdysozoa and Lophotrochozoa

Ecdysozoa

Animals that shed cuticles (ecdysis)

Lophotrochozoa

Taxonomic clade

Animals that have a trochophore larvae stage or a lophophore feeding structure

Dr. Vik Iyengar Science News

Signs of sexual selection: dimorphic sexes

Maritime Earwigs
- sexually-dimorphic weaponry, modified cerci

Male earwigs - ritualized/rather lethal fighting, more likely to cohabitate than females

Female earwigs - maternal care and aggression, lethal

Intrasexual Earwig Interactions

Larger earwigs outcompete smaller ones

Intersexual Earwig Interactions

Cohabitate with smaller partners

INVERTEBRATES I

divider

Janine Benyus

Wrote Biomimicry: Innovation Inspired by Nature

Invertebrates

Animals without backbones
Occupy almost every habitat on earth

True or False: There are more vertebrates than invertebrates

False

Phylum Porifera

Sponges

Features of Porifera

No tissues

No symmetry

Acoelomate

Lifestyle of Porifera

Mostly marine

Sessile

Filter feed

Asexual Reproduction of Porifera

External and internal budding

Fragmentation

Gemmules

Internal budding

Produced when dying and can remain dormant

Sexual Reproduction of Porifera

Sequential hermaphrodites

Porifera Feeding

Canals with flagellated chambers

**Choanocytes** more water from pores and food in

**Amoebocytes** digest and transport food

Bioutilization of Porifera

Cribrostatin kills cancer cells and strains of *Streptococcus* (NOT BIOMIMICRY)

Phylum Cnidaria

Corals, jellies, hydras

Features of Cnidaria

Diploblastic

Radial symmetry

Acoelomate

Forms of Cnidaria

Sessile polyp

Mobile medusa

Sexual Reproduction of Cnidaria

Two stages: sessile polyp and mobile medusa

Spawn with the moon phase

Asexual Reproduction of Cnidaria

Budding

Fragmentation

Split down middle

Feeding of Cnidaria

Tentacles capture and push prey into gastrovascular cavity

**Cnidocytes** used for capture and self defense

**Nematocysts** contain the stinging thread

Cnidaria have no centralized _______ but a

brain, nerve net

Portuguese Man o’ War

Colonial organism, made of specialized individual polyps

Function like a single animal

Phylum Cnidaria Class Anthozoa

Sea anemones, corals

Occur only as polyps

Have **zooxanthellae** in tissue

Zooxanthellae

Photosynthetic algae

Corals are signals of high _____

productivity and biodiversity

Clade Lophotrochozoa Phylum Platyhelminthes

Free-living and parasitic flatworms

Features of Platyhelminthes

Triploblastic

Bilateral symmetry

Free-living Platyhelminthes

Predators

**Ocelli** light sensitive eye spot

Sexual reproduction - hermaphrodites

Asexual reproduction - fission, budding

Parasitic Platyhelminthes

More than half

Multiple hosts in life cycles

Blood Flukes (Schistosoma)

Causes Schistosomiasis

2nd most socioeconomically devastating parasitic disease

Blood Flukes Life Cycle

Fertilized eggs exit in feces

Eggs develop into **miracidium**

Miracidium infect snails and turn into **cercaria**

Cercaria penetrate skin/vessels of humans

Miracidium

First larvae stage of blood flukes

Sessile larva

Cercaria

Second larvae stage of blood flukes

Motile larva

Clade Lophotrochozoa Phylum Syndermata

Rotifers

Features of Syndermata

Triploblastic

Bilateral symmetry

Pseudocelomates

Smaller than many protists

Clade Lophotrochozoa Phylum Ectoprocta/Bryozoa and Brachiopoda

Ectoprocts/Bryozoa and Brachiopods

When were Brachiopods most diverse?

Paleozoic and Mesozoic era

Features of Ectoprocta/Bryozoa and Brachiopoda

Triploblastic

Bilateral symmetry

Coelomates

CL Phylum Mollusca

Second most diverse phylum

Who has the most species, Brachiopods or Mollusca?

Mollusca

Features of Phylum Mollusca

Triploblastic

Bilateral symmetry

Coelomates

Mantle of Mollusca

Dorsal part of body

Covers visceral mass

Secretes CaCO2

Anus and genitals open into mantle cavity

Radula of Mollusca

Rough structure used for feeding (not in bivalves)

Circulatory system of Mollusca

Open, no veins or arteries

“Blood” pumped by heart into body cavity

Gastropods

Largest group of Mollusca

Most are marine, some freshwater and land

Bivalves

Group of Mollusca

Clams, oysters, mussels, scallops

Aquatic

Two shells with two adductor muscles

Filter feeders

Cephalopods

Group of Mollusca

Squid, octopus, cuttlefish, nautilus

Aquatic

Tentacles with suckers and a beak

Shell is internal, external, or nonexistent

What is the circulatory system of Cephalopods?

Closed

CL Phylum Annelida

Errantians and Sedentarians

Errantians

Mobile

Bristle structures on body segments

Sedentarians

Reduced or no parapodia

Earthworms and leaches

Features of Annelida

Triploblastic

Bilateral Symmetry

Coelomates

Body of Annelida

Segmented body, same set of organs per segment

Circulatory system of Annelida

Closed

Reproduction of Annelida

Sexual - most common, many hermaphrodites

Asexual - dividing, budding, regeneration after injury

Advantages of Segmentation

Repeatability

Hydrostatic skeleton (fluid skeleton)

Specialization (anterior “brain”)

Clade Ecdysozoa

Shed external coat

8 phyla

Most species in this clade (insects)

Review: What clade are Platyhelminthes?

Lophotrochozoa

Clade Ecdysozoa Phylum Tardigrada

“water bears”

800 species