1. Using the structural/behavioural adaptations unique to each phylum explain how Kingdom Animalia has increased from Phylum Porifera up to Phylum Chordata.
The first category of animals on the evolutionary scale are called the Lower Invertebrates. These organisms are typically very simple compared to the others. The first phylum is Porifera. These organisms include sponges and are the simplest of all. They do not have true tissues and have changed little since they evolved. The Poriferans have spicules or spongin to support themselves, filter feed, reproduce sexually via internal fertilization or asexually via gemmules, and use water to aid with almost all bodily functions (circulation, excretion, reproduction, etc). Even though sponges are the most primitive, they mark the beginning of multicellular animals. The next phylum of Lower Invertebrates include the Cnidarians, these organisms are quite advanced compared to the Poriferans. The Cnidarians have true tissues, are diploblasitc, have radial symmetry, have a nerve net nervous system, and an incomplete digestive system. Some example animals include jellyfish and hydra. The Cnidarians use an alteration of generations life cycle but with a motile medusa and stationary polyp stages. These organisms also have an amazing system of cnidocytes which are used for stinging their prey along with oceli (light detecting) and statocysts (gravity sensing). The Cnidarians reproduce sexually by motile gametes an asexually via budding. The next phylum of the Lower Invertebrates is Platyhelminthes, also known as the flatworms. Some of their advances include bilateral symmetry, triploblastic (however they still have a solid mesoderm), an excretory system of flame cells, amazing powers of regeneration, a nerve ladder type nervous system, and the beginning of cephalization. Some example animals include planaria and tapeworms. These organisms also have a separate mouth and anus, which is another large advancement. The final phylum of the Lower Invertebrates is Nematoda, also known as the roundworms. This phylum marks some major advances in evolution. The Nematodes have a complete digestive system, a pseudocoelom between the mesoderm and endoderm, and an anus. Even though the Nematodes seem very primitive, they are actually very well adapted to their habitat. There are both free-living and parasitic Nematodes. The Lower Invertebrates mark the beginning of the long evolutionary road to becoming highly evolved organisms.
The next step on the evolutionary scale include the Higher Invertebrates. These organisms are much more complex than the Lower Invertebrates and have even more evolutionary advancements. The first phylum is called Mollusca. The molluscs have three defining characteristics; a large ventral muscular foot, a visceral mass located dorsal to the foot, and a tissue layer called the mantle which covers the visceral mass. The molluscs are the first animals to have shells as well. Phylum Mollusca also includes Class Cephalopoda. This class is highly intelligent and includes organisms like the octopus, which are highly intelligent and are capable of learning. Class Cephalopoda are also very motile predators with incredible vertebrate eyes. The next phylum is Annelida, also known as the segmented worms. The Annelids mark some major advancements such as a true coelom, a single ventral nerve cord, an anterior brain, a circulatory system, five hearts, and specialized excretory units called nephridia. The Annelids have unspecialized segmentation and reproduce mainly sexually. This phylum is also a protostome. The next phylum is Arthropoda, also known as the "jointed legs". This is the largest phylum with some incredible advances. The Arthropods have an exoskeleton made chitin, the formation of appendages, high specialized segmentation, gills/tracheids/booklungs, separate sexes, a ventral nerve, an open type circulatory system with hemocoel, and an improved single heart. One of the major advances of this phylum is the ability to fly, which a reason for the Arthropods success. This phylum is also still a protostome. The next phylum is Echinodermata. Some example animals include starfish and sea urchins. These organisms have some advances such as a semi-flexible endoskeleton, pentaradial symmetry, the water vascular system, and tube feet. This phylum is also the beginning of deuterostomes (like us!). The water vascular system an amazing system used for movement, feeding, respiration, and circulation. The Higher Invertebrates developed important evolutionary traits that allowed for even more advances.
The next step in becoming fully evolved involves a phylum called the Chordates, this is the most advanced phylum and also includes humans. They all are coelomates (triploblastic) and deuterostomes. Within this phylum are many other important subphyla and orders. All chordates must have four defining characteristics; a notochord, a dorsal hollow nerve cord, pharyngeal gill slits, and a muscular, post anal tail. Subphylum Hemichordata includes the acorn worm, these organisms lack a true notochord but still contain the remaining three characteristics. Subphylum Urochordata includes sea squirts, the adult is a sessile, filter-feeding animal with no resemblance to a chordate. However, the juvenile exhibit all characteristics of a chordate and are fully motile organisms (for only 1-2 days however). The adult only has pharyngeal gill slits, but still qualifies as a Chordate. Subphylum Cephalochordata includes the amphioxus, which is called a "classical chordate" since it displays all characteristics as an adult. The fishes consist of Class Agnatha (the jawless fishes), Class Chondrichthyes (the cartilaginous fishes), and Class Osteichthyes (the bony fishes). They all have an endoskeleton of bone or cartilage, a reduced or absent notochord (as an adult), pronounced cephalization, and a closed circulatory system. They have the beginnings of specialized body systems which is a major advancement compared to the other phylums.The next is Class Amphibia which have some advancements such as crude lungs, a three chambered heart, functioning appendages which come off the side of their body, increased brain size, and improved senses (a land-based ear and a sense of smell). Amphibian young are a form of larva called tadpoles which are completely marine and use gills/fins, they undergo metamorphosis in order to become a land dwelling adult. The next is Class Reptilia which have some major advances such as an amniotic egg, internal fertilization, scales/plates, better function appendages found on the ventral side with claws, well developed lungs, and partial division of the ventricle. The amniotic egg solved the problem of water cased development, which allowed the young to be born on land. The improved lungs no longer require skin for getting oxygen, which allowed the Amphibians to cover their skin with scales. Behaviours also include mate selection and territoriality due to internal fertilization. The next is Class Aves which include advances such as a four chambered heart, being endothermic, wings, and lightweight bones. Class Aves also developed pre/post natal behaviours such as nesting. The four chambered heart was required for Class Aves due to the high energy demand from flight and being endothermic. Being endothermic means that an animal can maintain a constant body temperate regardless of external conditions (humans are also endothermic!). Finally, Class Mammalia brings us to the final evolutionary step. Some advances of Class Mammalia include a four chambered heart, a diaphragm for breathing, mammary glands for nursing, extensive post natal care, and high learning/reasoning capabilities. Mammals have even bigger brains and better senses. Mammal skeletons are well adapted for land as well as water. Overall mammals are far more advanced then any of the other classes or phylums. From Phylum Porifera to Phylum Chordata it's clear that our animal kingdom is very diverse with amazing animals with extraordinary traits.
The next step on the evolutionary scale include the Higher Invertebrates. These organisms are much more complex than the Lower Invertebrates and have even more evolutionary advancements. The first phylum is called Mollusca. The molluscs have three defining characteristics; a large ventral muscular foot, a visceral mass located dorsal to the foot, and a tissue layer called the mantle which covers the visceral mass. The molluscs are the first animals to have shells as well. Phylum Mollusca also includes Class Cephalopoda. This class is highly intelligent and includes organisms like the octopus, which are highly intelligent and are capable of learning. Class Cephalopoda are also very motile predators with incredible vertebrate eyes. The next phylum is Annelida, also known as the segmented worms. The Annelids mark some major advancements such as a true coelom, a single ventral nerve cord, an anterior brain, a circulatory system, five hearts, and specialized excretory units called nephridia. The Annelids have unspecialized segmentation and reproduce mainly sexually. This phylum is also a protostome. The next phylum is Arthropoda, also known as the "jointed legs". This is the largest phylum with some incredible advances. The Arthropods have an exoskeleton made chitin, the formation of appendages, high specialized segmentation, gills/tracheids/booklungs, separate sexes, a ventral nerve, an open type circulatory system with hemocoel, and an improved single heart. One of the major advances of this phylum is the ability to fly, which a reason for the Arthropods success. This phylum is also still a protostome. The next phylum is Echinodermata. Some example animals include starfish and sea urchins. These organisms have some advances such as a semi-flexible endoskeleton, pentaradial symmetry, the water vascular system, and tube feet. This phylum is also the beginning of deuterostomes (like us!). The water vascular system an amazing system used for movement, feeding, respiration, and circulation. The Higher Invertebrates developed important evolutionary traits that allowed for even more advances.
The next step in becoming fully evolved involves a phylum called the Chordates, this is the most advanced phylum and also includes humans. They all are coelomates (triploblastic) and deuterostomes. Within this phylum are many other important subphyla and orders. All chordates must have four defining characteristics; a notochord, a dorsal hollow nerve cord, pharyngeal gill slits, and a muscular, post anal tail. Subphylum Hemichordata includes the acorn worm, these organisms lack a true notochord but still contain the remaining three characteristics. Subphylum Urochordata includes sea squirts, the adult is a sessile, filter-feeding animal with no resemblance to a chordate. However, the juvenile exhibit all characteristics of a chordate and are fully motile organisms (for only 1-2 days however). The adult only has pharyngeal gill slits, but still qualifies as a Chordate. Subphylum Cephalochordata includes the amphioxus, which is called a "classical chordate" since it displays all characteristics as an adult. The fishes consist of Class Agnatha (the jawless fishes), Class Chondrichthyes (the cartilaginous fishes), and Class Osteichthyes (the bony fishes). They all have an endoskeleton of bone or cartilage, a reduced or absent notochord (as an adult), pronounced cephalization, and a closed circulatory system. They have the beginnings of specialized body systems which is a major advancement compared to the other phylums.The next is Class Amphibia which have some advancements such as crude lungs, a three chambered heart, functioning appendages which come off the side of their body, increased brain size, and improved senses (a land-based ear and a sense of smell). Amphibian young are a form of larva called tadpoles which are completely marine and use gills/fins, they undergo metamorphosis in order to become a land dwelling adult. The next is Class Reptilia which have some major advances such as an amniotic egg, internal fertilization, scales/plates, better function appendages found on the ventral side with claws, well developed lungs, and partial division of the ventricle. The amniotic egg solved the problem of water cased development, which allowed the young to be born on land. The improved lungs no longer require skin for getting oxygen, which allowed the Amphibians to cover their skin with scales. Behaviours also include mate selection and territoriality due to internal fertilization. The next is Class Aves which include advances such as a four chambered heart, being endothermic, wings, and lightweight bones. Class Aves also developed pre/post natal behaviours such as nesting. The four chambered heart was required for Class Aves due to the high energy demand from flight and being endothermic. Being endothermic means that an animal can maintain a constant body temperate regardless of external conditions (humans are also endothermic!). Finally, Class Mammalia brings us to the final evolutionary step. Some advances of Class Mammalia include a four chambered heart, a diaphragm for breathing, mammary glands for nursing, extensive post natal care, and high learning/reasoning capabilities. Mammals have even bigger brains and better senses. Mammal skeletons are well adapted for land as well as water. Overall mammals are far more advanced then any of the other classes or phylums. From Phylum Porifera to Phylum Chordata it's clear that our animal kingdom is very diverse with amazing animals with extraordinary traits.
2. In your opinion, which organism is best adapted to life on Earth and why?
I believe that humans are best adapted to life on Earth. We have the characteristics of a mammal which make us the most advanced of the classes, and also have developed the most evolved/efficient body systems. Humans have even developed technologies to make everyday survival easier. Other animals haven't even come close to a humans depth of understanding of the world around us (I don't think any giraffes do biology homework). Most humans do not even have to worry about their survival. Other animals might have more advanced senses or different adaptations for survival, but humans have been able to create new technologies to do these things for them. We might not have the amazing swimming capabilities of a dolphin, but we have machines and the technology to do that for us. Humans also have the most evolved brains by far as well, allowing us to even study biology!
3. In your opinion, is your portfolio a sound piece of evidence in support of the theory of evolution? Explain.
My portfolio supports the theory of evolution. If you read through each page it should be clear that life has evolved and adapted to survive. From the sponge to humans, it's clear that animals evolve over time to reach where they are today. Even from the simple bryophyte to the massive angiosperms, life on Earth has evolved for millions of years. I believe that my portfolio is sound proof of evolution and even shows how each phylum and plant type becomes more advanced than the previous to adapt to life on Earth.