vertebrate evo Flashcards
What are 4 anatomical features all Chordates have, what is their function?
- Notochord
- long flexible skeletal support
- between nerve cord and digestive tract - dorsal, hollow nerve cord
- turns into brain and central nervous system
- runs down length of organism - pharyngeal slits
- slits in pharynx that open to outside the body
- for vertebrates they’re for gas exchange
- for tetrapods they turn into parts of ears, head, neck - muscular post-anus tail
- movement and balance
- propulsion in aquatic species
- in many species, greatly reduced during embryonic development
What are craniates? What did this development help organisms do?
Chordates with heads.
gave them skull, brain, eyes, and other sensory organs. this allowed them to become more active and lead to active predation.
What are vertebrates, what did this development allow them to become efficient at?
Craniates with backbones.
This allowed them to become efficient
What are 3 derived characteristics of vertebrates?
- elaborate skull
- spinal cord enclosed by vertebrae
- fin rays (aquatic species)
Which vertebrate phylum are fish with cartilage skeletons?
Chondrichthyes
Which vertebrate phylum are fish with bone skeletons?
Osteichthyes
What are the two types of Osteichthyes, which gave rise to early tetrapods?
- Ray fin
- most familiar aquatic fish - Lobe fin
- gave rise to early tetrapods
- muscular pelvic and pectoral fins
5 main tetrapod characteristics
- 4 limbs with digits
- pelvic bones fused to backbone
- necks
- no pharyngeal slits as adult
- ears adapted to airborne sounds
Which vertebrate phylum do we see the start of some parental care? How? How is this progress in evolution?
Amphibia.
- some species carry eggs with them until ready to hatch.
- this means more babies will survive, eliminating the need for having to produce 100s of eggs
Which vertebrate phylum perform gas exchange through their skin?
Amphibia
In which vertebrate phylum do we start to see amniotic eggs?
Reptilia
What is an amniotic egg? What does it do and how is it significant in evolution?
Amniotic egg = embryo + food source + protection
- It allows the embryo to develop more before being exposed to the environment, and prevents the egg from drying out (unlike previous eggs of amphibians)
- significant in evolution because it breaks ties with aquatic habitats -> organisms can now develop away from water
What are amniotes?
Amniotes are organisms that have an embryo/fetus surrounded in an amniotic sac (either in egg or uterus). This includes reptiles, avion reptiles, and mammals
Other than an amniotic egg, what are 3 other terrestrial adaptations shared by amniotes?
- relatively impermeable skin
- elevated stance
- use of rib cage to ventilate lungs
Which vertebrate phylums are ectothermic?
Amphibia
Reptilia
