Lower Invertebrates
1. a) Porifera (the sponges) vs. Cnidaria (the jellies)
Phylum Porifera are the most basic lower invertebrates that don't consist of much. In contrast Phylum Cnidaria are more advanced than the Poriferians in many ways in which help them survive and are therefore more dominant in the environment. Firstly, unlike Porifera, Cnidarians have 2 germ layers which means they are diploblastic. This allows them to be more complex. Cnidarians also have radial symmetry while the Poriferians are asymmetrical. As far as food goes, cnidarians are able to hunt prey by containing tentacles with stinging cells known as cnidocytes. The Poriferians are only able to filter feed hoping that food travels near them. Also unlike the Poriferians who are sessile, Cnidarians are motile and contain a nerve net for muscle contractions (movement) and to sense the surrounding environment. The Cnidarians also contain a central mouth/anus for food intake and excretion and contain a gastro vascular cavity for intercellular digestion. In contrast the Poriferians only consist of a hollow space relying on choanocytes to filter and provide a water current for excretion and food movement throughout the Porifera. Some Cnidarians also contain ocelli which act as eyes and statocysts which act as balance receptors.
Phylum Porifera are the most basic lower invertebrates that don't consist of much. In contrast Phylum Cnidaria are more advanced than the Poriferians in many ways in which help them survive and are therefore more dominant in the environment. Firstly, unlike Porifera, Cnidarians have 2 germ layers which means they are diploblastic. This allows them to be more complex. Cnidarians also have radial symmetry while the Poriferians are asymmetrical. As far as food goes, cnidarians are able to hunt prey by containing tentacles with stinging cells known as cnidocytes. The Poriferians are only able to filter feed hoping that food travels near them. Also unlike the Poriferians who are sessile, Cnidarians are motile and contain a nerve net for muscle contractions (movement) and to sense the surrounding environment. The Cnidarians also contain a central mouth/anus for food intake and excretion and contain a gastro vascular cavity for intercellular digestion. In contrast the Poriferians only consist of a hollow space relying on choanocytes to filter and provide a water current for excretion and food movement throughout the Porifera. Some Cnidarians also contain ocelli which act as eyes and statocysts which act as balance receptors.
1. B) Cnidaria vs Platyhelminthes:
Moving up the chain Platyhelminthes; the flatworms are more complex than Cnidaria; the jellyfish. Firstly, Platyhelminthes are triploblastic and have bilateral symmetry unlike Cnidaria who are diploblastic and have radial symmetry. Platyhelminthes also are considered to have cephalization which is a huge advancement for environmental awareness. This means that sense organs and the "brain" is located at the anterior end. However, the brain of Platyhelminthes is still not fully developed and is known as a ganglia. Unlike Cnidaria, the flatworms are able to regenerate meaning that they can split in 2, creating another worm. Platyhelminthes also are hermaphroditic ( produces both sperm and egg) and are able to absorb nutrients through there skin. As far as excretion goes unlike Cnidaria, Platyhelminthes contain flame cells which allows them to excrete cellular wastes through its skin. The nervous system is also more developed as a flatworm as they contain a nerve ladder instead of a nerve net which isn't as organized. Overall many characteristics are similar between flatworms and jellyfish but a few keys advancements make Platyhelminthes more complex.
Moving up the chain Platyhelminthes; the flatworms are more complex than Cnidaria; the jellyfish. Firstly, Platyhelminthes are triploblastic and have bilateral symmetry unlike Cnidaria who are diploblastic and have radial symmetry. Platyhelminthes also are considered to have cephalization which is a huge advancement for environmental awareness. This means that sense organs and the "brain" is located at the anterior end. However, the brain of Platyhelminthes is still not fully developed and is known as a ganglia. Unlike Cnidaria, the flatworms are able to regenerate meaning that they can split in 2, creating another worm. Platyhelminthes also are hermaphroditic ( produces both sperm and egg) and are able to absorb nutrients through there skin. As far as excretion goes unlike Cnidaria, Platyhelminthes contain flame cells which allows them to excrete cellular wastes through its skin. The nervous system is also more developed as a flatworm as they contain a nerve ladder instead of a nerve net which isn't as organized. Overall many characteristics are similar between flatworms and jellyfish but a few keys advancements make Platyhelminthes more complex.
1. C) Platyhelminthes vs Nematoda:
Although these are both worms Nematoda are roundworms while Platyhelminthes are flat worms. Nematoda are considered to be more advanced than Platyhelminthes based on various body structures to better its survival. Phylum Nematoda are triploblastic just like Platyhelminthes but now contain a speudocoelom which is a false body cavity. This is a huge advancement because now more important and complex organs are able to form inside the body. However, since the body cavity is false much of this is empty space. Nematoda also are considered to be a tube with in a tube meaning that the body is a tube which contains another tube which is the digestive system. Unlike Platyhelminthes Phylum Nematoda have a complete digestive system consisting of a mouth and anus. This is very important because now these worms are able to from their mouths and release wastes from the anus. Overall, Nematoda consists of some critical advancements over Platyhelminthes but many characteristics also haven't changed.
Although these are both worms Nematoda are roundworms while Platyhelminthes are flat worms. Nematoda are considered to be more advanced than Platyhelminthes based on various body structures to better its survival. Phylum Nematoda are triploblastic just like Platyhelminthes but now contain a speudocoelom which is a false body cavity. This is a huge advancement because now more important and complex organs are able to form inside the body. However, since the body cavity is false much of this is empty space. Nematoda also are considered to be a tube with in a tube meaning that the body is a tube which contains another tube which is the digestive system. Unlike Platyhelminthes Phylum Nematoda have a complete digestive system consisting of a mouth and anus. This is very important because now these worms are able to from their mouths and release wastes from the anus. Overall, Nematoda consists of some critical advancements over Platyhelminthes but many characteristics also haven't changed.
2. Parasitic worm vs Free-living worm:
Parasitic worms and free-living worms may seem very similar but there are some key differences that which makes them both successful at what they do. Free-living worms are located in marine or fresh water and scavenge the sea bed for food. They either are carnivorous, feast on algae or other tiny plants, or are decomposers feeding on decaying organic matter. The free-living worms also contain sensory organs and ocelli which are used to help detect the area around them. In contrast parasitic worms require a host to feed on and are considered to be less advanced because its host provides most of its survival. For example, parasitic worms don't scavenge for food, and contain little to no sensory organs and ocelli. This is because they have no need for eyes as they are rarely moving and constantly living in the dark inside their host. Also many parasitic worms absorb nutrients through their skin which may seem outdated but they do this because a constant food source is right in front of them, Their host. Overall, free-living worms have greatly adapted to the outside world in oceans and lakes, while parasitic worms even though they may seem basic, also have developed essential tools able to survive in a host. However, parasitic worms also face the risks of killing their host which would also kill themselves.
Parasitic worms and free-living worms may seem very similar but there are some key differences that which makes them both successful at what they do. Free-living worms are located in marine or fresh water and scavenge the sea bed for food. They either are carnivorous, feast on algae or other tiny plants, or are decomposers feeding on decaying organic matter. The free-living worms also contain sensory organs and ocelli which are used to help detect the area around them. In contrast parasitic worms require a host to feed on and are considered to be less advanced because its host provides most of its survival. For example, parasitic worms don't scavenge for food, and contain little to no sensory organs and ocelli. This is because they have no need for eyes as they are rarely moving and constantly living in the dark inside their host. Also many parasitic worms absorb nutrients through their skin which may seem outdated but they do this because a constant food source is right in front of them, Their host. Overall, free-living worms have greatly adapted to the outside world in oceans and lakes, while parasitic worms even though they may seem basic, also have developed essential tools able to survive in a host. However, parasitic worms also face the risks of killing their host which would also kill themselves.
3. Necator (Hookworm):
The necator hookworm is a parasitic roundworm that is common around the world (mostly is areas with bad hygiene. The necator first attaches to an unprotected foot where it creates an itchy feeling causing the human to scratch creating cuts. Then the hookworm enters into its hosts bloodstream where it travels to the lungs for oxygen and then forces the host to cough then swallow the worm until it reaches the small intestine. This is the Necators home and is where it will grow from a baby worm to an adult. Then eggs are produced via sexual reproduction and are released by feces. This worm can cause weakness and poor growth and can be prevented by wearing shoes or protective covering over your feet. Also try not to scratch your foot if it feels itchy. The Necator also starts as an egg in the soil, hatches and is in the juvenile stage when it burrows into its host.
The necator hookworm is a parasitic roundworm that is common around the world (mostly is areas with bad hygiene. The necator first attaches to an unprotected foot where it creates an itchy feeling causing the human to scratch creating cuts. Then the hookworm enters into its hosts bloodstream where it travels to the lungs for oxygen and then forces the host to cough then swallow the worm until it reaches the small intestine. This is the Necators home and is where it will grow from a baby worm to an adult. Then eggs are produced via sexual reproduction and are released by feces. This worm can cause weakness and poor growth and can be prevented by wearing shoes or protective covering over your feet. Also try not to scratch your foot if it feels itchy. The Necator also starts as an egg in the soil, hatches and is in the juvenile stage when it burrows into its host.
4. Ascaris Dissection: Since the picture isn't very clear, the anus is at the posterior end, the seminal vesicle is the largest tube, the vas deferens are the medium sized tubes, and the testes are the smallest ones. The digestive tract is also fairly wide but it is flat.