Intro to Vertebrates

Metazoa

All animals

Animals

multicellular organisms that are eukaryotic

Bilateria

animals that are a mirror image on both sides: protostomes and deuterostomes

Are vertebrates protostomes or deuterostomes

Deuterostomes

What are the characteristics of vertebrates as a group?

1. Deuterostomes: anus first

2. Notochord: stiffening rod that is replaced by vertebral column

3. Dorsal hollow nerve cord

4. Structure that pumps blood

5. Endostyle: the ciliated groove in non-vert chordates that is now part of our thyroid gland

6. Post anal tail

What distinguishes vertebrates?

• serially arranged bones that make up the spine and neck

• cranium: hard brain covering of some sort

• head with sensory tissues

• mineralized tissues

What are the types of vertebrates?

Non-amniotes and amniotes

Amnion

the innermost membrane of substance surrounding the embryo

• yolk sac provides nutrients

During what period where the only vertebrates fishes?

541-359 million years ago

When did the first tetrapods come about?

Carboniferous period

What is the current mass extinction event called?

Holocene extinction

What was the “birthplace” of terrestrial vertebrates?

Tropics of Pangea

When did the first terrestrial vertebrates hit the scene?

150 million years ago

What makes up non-amniote vertebrates?

Fishes

Amphibians Wha

What makes up amniote vertebrates?

Reptiles (turtles, lizards, birds, crocodiles)

Mammals

What is the biggest driver of anatomical differences in non-vert chordates vs vert chordates?

The level of energy that they expend to eat (filter feeding to active feeding)

What are the 4 major tissue types?

• Epithelial

• Muscle

• Nervous

  • Connective

What are the 5 major systems that signal adaptations in vertebrates?

• Alimentary

• Circulatory

• Excretory

• Reproductive

• Sensory

Describe the alimentary system:

Digestion:

• Particulate feeders move food down the gut via muscular contraction

• The animals shape and length dictates what they eat

Describe the circulatory system:

Activity:

• Shown through heart shape and size

• based on energy requirements on the organism

Describe the excretory system:

Regulate chemical composition of body fluids

• High pressure and salinity impact this highly - important for aquatic animals

Describe the reproductive system:

Animals can have internal or external fertilization and development

• Oviparous: lay eggs - external development

• Viviparous: give live birth - internal development

• Ovoviviparous: have eggs but give live birth - weirdos

Describe the sensory system

Organs change in structure vastly depending on life history:

• Smell/taste - chemo

• Vision

• Balance and orientation

• Electroreception (mostly fishes) - contraction of muscles in the water

• Mechanoreception (only with aquatics) - feel movement in the water

• Hearing

What are the 4 species concepts used to try to classify vertebrates?

• Morphological species concept: things that look alike are the same species

• Biological species concept: things that can mate are the same species

• Phylogenetic species concept: things are a species if they share a unique common ancestor

• Cohesive species concept: things that have the same genetics are a species

Define systematics

Evolutionary classification of organisms

Phylogenetic systematics

A hypothesis:

• assesses similarities between organisms from evolutionary context

• uses parsimony - the simplest track is the best answer

Divergent evolution

structures are derived from shared ancestor

• homologous structure

• may look very different but arose from the same origin

Convergent evolution

Similar structures arise due to the same environmental conditions but evolved independently

• analogous structures

• look the same but did not come from the same origin