Using the Structural/Behavioral Adaptations Unique to Each Phylum, Explain how Animalia has increased in complexity from Phylum Porifera to Phylum Chordata.
The first and most simplistic animal to begin on our bottom rung of the complex ladder that is the Kingdom Animalia is the sponge from Phylum Porifera. Sponges started out very simplistically. Sponges are the first multicellular animal yet their cells do not act as tissue, although their cells do co-ordinate with one another. A sponge lacks a nervous system and has a rather rudimentary digestive, reparatory, and reproductive system all based of the flow of water. Water will flow in a sponge through one of its many ostrum, this water will push out old nutrient lacking water and allow for the new nutrient rich water to enter. Any nutrients that can be caught on collar cell flagella like structures will be food for the sponge. This water also brings in oxygen for the sponge and outgoing water carries out metabolic waste. All the water going out goes out through the osculum. This water flow also allows for eggs and sperm to be released with the hopes of fertilization. This system reliant on water flow is unique however not totally sustainable with an astounding efficiency. Continuing, a sponge has no body layers, symmetry, mouth, anus, gastro vascular cavity, it truly is rudimentary. The next Phylum is Cnidaria containing the Jellyfish. Jellyfish have advanced a fair bit from the sponges. Their reproductive cycle is better adapted to aquatic life. As they have an alteration of generation cycle they have motile medusas which can spread their DNA through sexual reproduction as well their ployps are able to bud many medusas. As well jellyfish have a dedicated gastro vascular cavity for digestion and a mouth/anus. Jellyfish have a nerve net a simplistic nervous system and have actual tissues. All animals of the Cnidaria have radial symmetry and two body layers. As well jellyfish have highly adapted cnidocytes on their tentacles, these are essentially the "stingers" of the jellyfish and are extremely helpful in their catching of prey. Moving on the next evolutionary step is Platyhelminthes, an animal of this phylum is a planarian or a tapeworm. Animals of the Platyhelminthes display anterior cephalisation, the start of an anterior "brain", as well they have a nerve ladder a more sophisticated layout of nerves. They developed eyespots for sense . Their digestive system became more advanced because of their excretory cells or "flame" cells dawning the separation of mouth and anus. Planaria have the ability to evert their pharynx, a good way to feed. Most animals of this phylum are hermaphroditic. The parasitic animals also made great adaptation advances, although their lack of eyespots may seems degenerative, their other adaptations such as their hooks and suckers on their scolex are well adapted parasitic features. Many animals of this phylum also have great abilities of regeneration. The next Phylum is Nematoda. These mostly parasitic animals have evolved digestively to have a true "tube within a tube" digestive layout and seperate mouth and anus. Majority of these animals are separate sexes. They parasitic are very well adapted to being parasites. Hookworms, Ascarises, and Trichina all have different ways to get into the human body and ways they benefit from being parasites of humans. The next phylum is Annelida. These animals are the first to have a true coelome and the point at which, evolutionarily, deuterstomes and protostomes separate. Annelids have a more co-ordinated digestive system as their digestive tract has more muscular capability. They now have a ventral nerve as well. they now have an oxidated heart, rather than having a circulatory system relying on diffusion. Their excretory system has also greatly advanced as they have kidney like nephridia which are for nitrogen wastes. Annelids display simple segmentation a completely new charecteristic. Segmentation is a major step towards specialized body sections. Their marine life animals have crude gills and crude appendages, like on the sandworm, this was a huge stepping stone. Moving onto Phylum Mollusca the next evolutionary rung. Molluscs have three main body characteristics a muscular foot, visceral mass and mantle (which can excrete CaCO₃ which will become a shell.) Molluscs are soft bodied creatures, however their ability to have a shell is a great adaptation for protection, especially for their sessile, or slower animals. Molluscs mark the point at which senses started to become much better. A squid or octopus has very similar eyes to a human although they lack a blind spot and cone cells. Molluscs have segmented larvae as well. A major advance that Molluscs also have is their intelligence, their most advance animals, octopi, have the ability to open jars, they can find food in aquariums that is locked away, they are increasing in intelligence. The next rung on the evolutionary ladder is Phylum Arthropoda. A major distinction for Arthropods is their Chitin based exoskeleton. This exoskeleton is a fantastic advance, it gives durability, protection, and camouflage for animals and with their softened exoskeleton at joints it allows movement. The respiratory system of these animals is incredible, they have book lungs (high surface area/efficient lungs - arachnids), traechids (openings in exoskeleton for respiration) and more efficient gills. Their ability for highly specialized segmentation is great, insects able to fly with their specialization. Arthropods are the last of the protostomes on the evolutionary ladder. The next phylum is Echinodermata where our lovely seastar resides. Seastars are the first deuterstomes. They have an endoskeleton composed of ambuacrul plates (calcium based). They have pentaradial symmetry. Seastars have a unique complex watervascular system that aids in its digestive, circulatory, and respiratory system. This system however relying on water like a sponge, is much more concise and efficient with dedicated pathways, entrance, and exits. A sponge displays great advance in its feeding ability, it can evert its cardiac stomach into its meal (opening of a clam) a digest partly and ingest food. It will open the clam with its tube feet upon which are eyespots and the end and a sucker like structures called ampulla. Continuing, the next evolutionary advancement would be the Chordata, firstly the Lower Chordata. An animal residing in the Lower Chordata would be a tunicate. This animal has a hollow dorsal notochord. It is sessile in its adult stage however motile as a larvae. Although the larvae only stays in that form for 1-2 days, this period evolutionarily would be extended if it were to more succssful, leading us into our next section of the Phylum Chordata, Higher Chordata. The first Sub-Phylum is Osteichthyes containing fish like a perch. A perch has a 2 chambered heart that recieves deoxygenated blood in the atrium and pumps it through the ventricle to the gills to be oxygenated, then the blood is sent to the rest of the body, this system works but it is not substantially efficient. As well it has well developed lungs. Osteichthyes display the major development of behaviour, travel in schools of fish. This is a major advance in intelligence. These animals fertilize their eggs externally, as well, their offspring is self sufficient and usually requires minimal post natal care. The next Sub-Phylum is Amphibia. Amphibians were the "first attempt" to make it on land and they were somewhat successful. Let's use a frog as an example. It's larvae, a tadpole, is water bound and very motile. It hatches from a externally fertilized, waterborne egg. The tadpole with a complete gills later undergoes metamorphoses and become a frog. A frog has crude lung sacs and still relies on most skin for 50% of its land respiration. As well its heart has only 3 parts, 2 atria and 1 ventricle. This heart is inefficient as it mixes oxygenated and deoxygenated blood together. As well amphibians have lateral limbs causing their bellies to drag on land, this is inefficient for land based movement. However the size of an Amphibian's cerebrum and cerebellum increase a fair bit for land adaptation, as well their sense of smell and hearing better adapt to life on land. The next rung on the ladder would be Sub-Phylum Reptillia. Reptilians are significantly better adapted to live on land the Amphibians. Firstly, for reproduction, reptiles have internal fertilization and lay leathery amniotic eggs which are no longer waterborne. As well they now have a 3.5 chambered heart with 2 atriums, 1 ventricle, and a separation in the ventricle. This separation minimizes the mixing of oxygenated and deoxygenated blood, however there is still mixing. This is much more efficient. As well they have better developed lungs. A reptiles scales are better for more climates on Earth, as they are exothermic, and it prevents desiccation. A reptile's limbs come off of the ventral surface making land based movement much more efficient. Some reptiles also dsiplay territorial and mate selection (natural selection) behaviours, this causes an increase in cognitive ability and increased the size of their cerebrum and cerebellum. The largest of the reptiles, the crocodiles and alligators have 4 chambered heart to maximize efficiency. The next Sub-Phylum is Aves, the birds. It is likely that reptiles evolved into birds, despite sounding odd, because they have reptile like claws, teeth, and tail; as well feathers are genetically, very similar to scales. These animals adapted feathers for flight, and insulation as they are endothermic. Their ability to fly has a high metabolic cost, however it enables them access to the huge medium of free air. Reproduction of the Aves improves upon reptiles with calcified shells for incubation and nesting with post natal care. A bird's cloaca can store sperm for 1-52 weeks creating a greater potential for more offspring. Post natal care increases the Aves' intelligence and coincidently, their cerebrum and cerebellum increased in size and capability. As well a bird's outstanding sight increases the optic lobe's size. Bird's have 4 chambered hearts and they developed a spleen for recycling/replacement of blood cells. The final Sub-Phylum is Mammalia including animals like a rat, or us, Humans! Mammals have fur or hair for insulation as well as subcutaneous fat as we are endothermic. Reproduction of mammals advanced quite a bit. Mammals have internal fertilization and a modified amniotic egg. As well exclusive to mammals, we have mammary glands for nursing offspring and a placenta for the fetus. Mammal young are extremely immature and require extensive post-natal care. The diaphragm aids in the contraction and expansion of the lungs, negative pressure causing air to seek equilibrium makes the mammal lungs very efficient. As well the 4 chamber heart with complex circulatory system contributes to amazing efficiency. And finally the intelligence of mammals is extensive. We have a convoluted cerebrum to increase capacity as well as extensive growth of the cerebellum and other regions of the brain. Mammals are capable of reasoning, and learning and have complex advanced behavioural traits such as society. This concludes my explanation of how animals advanced from Phylum Porifera to Chordata.
In Your Opinion, Which Organism is Best Adapted to Life on Earth and Why?
In my opinion, in a sense of what organism is best adapted to LIFE on Earth I would say it would be insects from Phylum Arthropoda. Now, typically someone would say Humans due to egotism ;) and the fact that we are inarguabley the most complex, intelligent organisms on Earth, however,this is about what organism is best ADAPTED. Insects are very well adapted to live on Earth. Firstly they make up 65-70% of all animals on Earth! They posses this dominant number because they are so well adapted to live in each and every varying niche on Earth. Because of their incredibly small size they can inhabit almost any niche whether it be in the woods, a desert, the cold mountains, or within tiny pockets of man made structures (concrete, walls, etc.) Insects can live virtually anywhere because of their small size this flexibility is huge on Earth as Earth has thousands of different niches. Continuing, their size also allows them to be much more efficient, they require less food. This is huge, life is competition, and when you need less resources to "win" or succeed this is a huge advantage insects have. Their small size also means shorter life spans but at the same time this contributes to their lack of need for many resources. As well, insects have amazing proliferation capabilities. Their ability to proliferate makes reproduction faster, which means they'll create new generations faster, and better. All of their reproduction is sexual too, which means their is greater allele variation which means natural selection will occur. These short life spans with short generations allow for insects to evolves faster relative to other organisms like humans. As they evolve faster with their short quick generations they can adapt to their changing environments with new adaptations and specializations. Which is yet another reason why insects are best adapted to life on Earth as they have highly adapted appendages. Different insects, depending on their niche, require different appendages, as they evolve quickly they can develop these appendages so that they can be successful in their environment. Some of these appendages can be wings which enable flight. Flight is an adaptation that is extrodinary, although it requires a lot of energy, it has many benefits. Flight open up a huge medium (air) that enables easier travel, better parasitism (mosquito), and enables insects to get to new niches. Another reason why insects thrive is because they reduce competition amongst themselves. Despite being such a large chunk of the animals on Earth they are so spread out, and they are so small they reduce their competition as they are not even near each other. They have their own specific niches in which they fill and thrive in spread out across Earth. Continuing they have evolved intelligence and have behavioral characteristics. An ant for example lives in a colony, they have specific roles for each ant so that they can accomplish work, gathering food, "construction", etc in an efficient, organized manner. This makes them stronger in groups and capable of each working to their best ability without wasting energy on other jobs better completed by other ants. Ants are so intelligent in colonies that they can mark trails to food with pharamones to communicate with other ants, as well they pharamone trails maximize pathing efficiency so that roads do not experience "traffic jams." Ants are just one example of an insect with behavioral characteristics that benefit it's species and maximizes it's colonies efficiency while reducing competition by just filling their own specific niche. As well insects all have exoskeletons. Exoskeletons allow insects to survive harsh conditions on Earth and are great for protection. Their exoskeletons also can camouflage; this is an amazing ability as it increases the survival of insects greatly as they can go unseen by predators or their exoskeleton will be to difficult to pierce. For these reasons I think would be insects from the Phylum Arthropoda.
In Your Opinion, is Your Portfolio Evidence for the Theory of Evolution? Explain
In my opinion, I do think my portfolio is evidence for evolution. This is evident in my lab and other detailed conclusion question regarding the advances through phyla. These advances in complexity from phylum to phylum are examples of microevolution, which as they accumulate become macroevolution, from one organism to another. Although the portfolio doesn't mention the key animals at which certain phyla are connected to, it illustrates the traits and characteristics shared by different phyla and how they have had each advanced. As well the labels display the advances in body systems between animals of more and more complex animals. For these reasons, I would confidently say that my portfolio is evidence for evolution by illustrating micro evolutions resulting in the macro evolutions of animals of which we can see today.