Bio - Module 11 (Animal Evolution)

characteristics of animal and fungi

eukaryotic, multicellular, and heterotrophic

difference between animals and fungi

fungi have cell walls

animal clade

metazoa

what classification is based on 

embryology, morphology, and genetics 

animal body planes

asymmetrical, radial, bilateral

asymmetrical

irregular in shape

radial

central body axis and thus many planes that divide the animal into mirror image halves

bilateral

have an anterior-to-posterior body axis that divides the animal into mirror image halves

male sex cells

motile

female sex cells

non-motile

haploid

one set of chromosomes

fertilization 

union of a sperm and an egg to form a new cell called a zygote

diploid

2 sets of chromosomes

zygote

diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum

germ layers

give rise to specialized tissue and organ systems

endoderm 

inner lining of digestive tract 

ectoderm

covers exterior of the animal + forms nervous system

mesoderm

various structures like muscles, bones, + some visceral organs

blastopore

first opening to develop in the embryo

protosomes 

animals that form mouth first 

deuterostome

animals that form anus first

Hox genes

“master control genes”, they turn off and on many other genes involved in animal development

duplication of Hox genes function 

allows for greater morphological complexity in more recently evolved animals 

representative taxa of the metazoan clade

sponges

derived characteristics of the metzoans

absence of cell walls, multicellular, heterotrophic

eumetazoans representative taxa

comb jellies 

eumetazoans derived characteristics

endoderm + ectoderm, specialized tissue

bilaterians representative taxa

8 animal phyla

bilaterians derived characteristics

Mesoderm, bilateral symmetry  

deuterosomes representative taxa 

sea star 

deuterosomes derived characters

Anus develops before mouth from blastopore  

chordates representative taxa

lancelets

chordates derived character 

Notochord; dorsal hallow nerve cord; pharyngeal slits, post-anal tail  

craniate representative taxa

hagfishes

craniates derived characters

Skull protecting a brain and sense organs, pharyngeal GILL slits, 2-chambered heart, duplication of Hox genes

vertebrates representative taxa

lampreys

vertebrates representative characters

Vertebral column, improvements in skeleton and gills 

gnathostomes representative taxa 

cartilaginous fishes 

gnathostomes derived characters

Jaws with teeth, paired fins, lateral line, 2^nd duplication of Hox genes

bony “fishes” representative taxa

ray finned fishes (lung becomes swim bladder)

bony “fishes” derived characters 

lungs 

lobe-finned fishes representative taxa

lungfish

lobe-finned fishes derived characters

Paired fins with strong support of bone + muscle; basal bone of front (pectoral) fin is the humerus, 3CH

tetrapods representative taxa (1)

amphibians 

tetrapods derived character (1)

four limbs with toes 

tetrapods representative taxa (2)

amniotes

tetrapods derived character (2)

amniotic egg; rib cage ventilation; dry, impermeable skin

comb jellies

rotational symmetry

jelly fish 

radial symmetry 

derived character between comb jellies and jelly fish

one set of hox genes

debate about comb jellies

we are unsure their placement compared to sponges - genetically makes sense if comb jellies being first, but that would be that sponges lost layers and tissues

large reason for derived characters of the bilaterians

improves ability of prey capture and predator avoidance

deuterosomes show ___________ symmetry in the larval stage, but _________ symmetry in the adult stage

bilateral, radial

pentaradial

5 arms around central axis

special feature about the derived characters of chordates

they all are either present in the embryo or adult stage 

• this depends on the species 

characteristic of craniate

they are more active hunters

lateral line

row of sensory structures to detect movement and vibrations in the water

why there are quotations around fishes in bony “fishes”

they are not all fish, some are tetrapods

swim bladder

organ of buoyancy that evolved from lung

• increases or decreases buoyancy, allowing them to not need to keep swimming

benefits of 3 chambered heart

can have one circut to the lungs and another to the rest of the body

• keeps blood pressure high

characters

traits that unite the entire clade

cause of the change in body planes between jelly fish and comb jellies 

occurrence of Hox genes 

animal studied to discover Hox genes

fruit flies

use of the vertebral column

makes them more flexible and helps with muscle attachment and propulsion

shared derived character of reptiles

scales

reptiles representative taxa

turtles, lizards, crocodilians

dinosaurs representative taxa

other dinosaur group, feathered dinosaurs (we write these as T.Rex and Velociraptor)

birds representative taxa

archeopteryx and modern birds

mammals representative taxa

monotremes, marsupials

eutherians representative taxa

other eutherian groups, primates