L19 - Intro to Vertebrates & Early Jawless Fishes

Vertebrates are a part of what phylum?

Chordates

Why should we care about conservation?

Biodiversity

What is conservation?

Protecting Earth’s biodiversity

• species, habitats, and ecosystems

What is the IUCN?

International Union for Conservation of Nature

What does the IUCN do?

They have a goal to protect nature and conserve life on Earth.

Have an organization of all conservation status pf biological species

What is biodiversity?

Variety of different life forms on Earth, and the variations in the species.

• Taxonomic

• Ecological

• Morphological

Important for conservation

What is the red list for IUCN

Labels species in terms of how endangered they are or extinct

What is mass extinction?

High rate of extinction

What are some of the mass extinctions?

1. Ordovician: 86%

2. Devonian: 75%

3. Permian: 96%

4. Triassic: 50-75%

5. Cretaceous: 75% (dino)

6. Holocene (now): ?%

What is the holocene extinction?

Extinction happening now that is anthropocene meaning it is induced by humans

What caused many vertebrate extinctions in the last 50000 years?

Humans

What is the most detrimental factor humans induce on animals that cause their extinction?

overhunting, habitat loss

How Can We Successfully Conserve
Vertebrates?

Be reactive vs Proactive

What is a method for successful species conservation?

• Maintaining multiple populations across ecological settings with replicated populations in each setting

• Self sustaining, healthy and genetically robust pop’s

• Resilient to climate change and other environmental changes

What feature appeared right before Chordates branched off?

Neural crest

What is the neural crest in Chordates?

An infolding of the ectodermal layer into almost a new germ layer…might be called quadroblastic

What are the synapomorphies of the subphylum Vertebrata?

• Tripartite brain

• Mineralized tissue

• Pair of semi-circular canals

• Ectodermal placodes

• Homeobox (HOX) genes double duplication

What does the neural crest lead into in Chordates?

A tri-partite brain

• forebrain, midbrain, hindbrain

What does the forebrain house?

• Cerebral cortex

• The main processing centre of the brain

What is another synapomorphy in subphylum vertebrata?

Mineralized tissue

What are examples of Mineralized tissues?

• Cranium

• Vertebrae

What are semi-circular canals?

Craniata has them.

Part of their inner ear and help determine balance

What are ectodermal places

epidermis thickening leading to sensory system

What is the synapomorphy ”Double duplication Homeobox genes” in the subphylum Vertebrata?

2 sets of genes that are like a body plan and code for specific parts of the body so additional proteins can be made for the specific regions

How did vertebrates get so big/fast/smart

• Endoskeleton allows us to grow much bigger

• Physiology—Modifications of different systems to meet higher metabolic demand

• Tripartite brain

The forebrain houses what system?

Olfactory system

The midbrain houses what system?

ocular system

The hindbrain houses what?

balance, hearing, taste, touch, respiration and circulation

What is Myllokunmingia?

Earliest known vertebrate

• no vertebrae but a cranium

What is Haikouichthys?

Vertebrate feauteres

• cartilaginous gill supports

What is the functional group Ostracoderm?

Armored jawless fishes

• no jaw but have armour

What are the two groups of the Ostracoderm functional group?

1. Heterostracans

2. Myopterygians (Osteostracans and Anaspids) → extinct