Unit 10 Animalia Evolution + Phylogeny part 2

What is the current hypothesis scientists have about organisms related to each other?

That the relatedness of organisms change if the data changes

What are the 5 major things about the phylogeny tree scientists agree on?

1. all animals share a common ancestor

2. sponges (phylum Porifera) are basal animals

3. Eumetazoa is a clade of animals w/ true tiss

4. most animal phyla belong to the clade of Bilateria

5. most animals are invertebrates = no backbone

What is phylum porifera?

sponges that are asymmetric + lack true tiss

What is a lophophore?

a feeding appendage w hollow tubes

What is a protosome?

an org that’s mouth devels b4 the anus

What is Ecdysozoa?

• mot species rich

• covered by a tough coat (cuticle)

• cuticle is molted through a process called ecdysis

What is ecdysis?

the shedding of old exoskel (molting)

When did land animals move to land?

anthropods- 450 mya (1st)

vertebrates- 365 mya

What made insects so successful?

• short life span → quick adaptations

• small → live anywhere

• flight

What common traits appear in phylum Chordata?

• animals w/ backbones

• notochord + a dorsal hollow nerve chord + gill slits + a tail

• bilateral symmetry

• triploblastic

• cephalization

• complex organ systems

What was the earliest Vertebrate?

• myllokunmingia= oldest fossil fish

• they had a new type of int body support → vert column allows for movement in an entirely diff way

How did jaws evolve?

• devel from gill slits

• can eat larger/more varied food by shredding/tearing

How did animals transition to breathing air when moving onto land?

• gills are good at extracting O2 from water, but they need to be in H2O

• Solution= lungs → gas exchange transferred from gills to lungs which evolved from air sacs (swim bladder)

How do lungfish breathe?

using both gills + lungs

What are lobed fins?

round shaped bones surrounded by muscle

What did animals need in order to move onto land?

limbs for strength + to support weight

Life + Characteristics of amphibians

• live 2 lives → devel ( in water) + adult (land)

• skin moist + snooth → helps them to breathe but also a problem

• restricted to moist habitats

Evolution of the Amniotic Egg

• shell that retains water (or is lost when kept inside mammals)

• spec extra embryonic membranes

• entire life cycle of animal now on land

• in mammals + reptiles

What is an amnion?

protects from dehydration + mech shock

What is allantois?

stores waste in an amniotic egg

What is chorion?

gas exchange in an amniotic egg

Purpose of the yolk sac?

nutrient storage in an amniotic egg

What are the common traits of reptiles?

• emerged 315 mya

• have scales → creates a waterproof barrier

• most lay shelled eggs on land

• most are ectothermic, absorbing ext heat ( main source of body heat)