aprisby's blog

While much time and energy has been depleted discussing how it would be accomplished and which species would serve as practical candidates for de-extinction, there has been little talk about how species would be reintroduced into the wild, or if it even has a place anymore. If an ecosystem has been altered significantly since a species went extinct, a reintroduced species could wreak havoc on existing species. De-extinct species would be alien and potentially invasive when introduced to their primitive terrans, resulting in further devastation to already crumbling ecosystems. Both old habitats and food sources have changed in their absence; therefore de-extinct species’ roles in these ecosystems have transformed as well. Passenger pigeons, which are a primary candidate for de-extinction, served as a keystone species and major food source for carnivores including foxes, lynx, raccoons, marten and mink, falcons, and hawks in North America during early 1800s (The Passenger Pigeon, Craig Kasnoff, 2017). Sadly, these beautiful birds were reduced to their last individual Martha who died in 1914- more than a century passing since their total demise. The environment has learned to exist without them, as this is more than a substantial amount of time for its natural environment to adapt to new resources in their absence. The truth of the matter is, the passenger pigeon’s homeland will be unrecognizable- the environment does not need passenger pigeons anymore, yet de-extinction would mean reintroducing them to a new world that does not need them. Some scientists suggest the use of self-contained mini ecosystems to gage how a resurrected species might interact with existing ones. This would be conducted under extremely controlled conditions where scientists can predict the safety to reintroducing the species to the target environment. However this would unfortunately only provide a broad estimate, and under the unpredictability and utter harshness of the natural world we cannot predict exactly what will happen when we release these hybrids to the delicate fabrication of the wild. If these new, genetically modified birds become invasive to U.S. lands, the damage will be irreversible. There are no “maybes” to such a precise decision, it either must be executed correctly and just, or not until we have concrete evidence of the benefits de-extinction holds first.

The two multi-panel scientific figures created by the original student and the second student showed several observational differences. Upon initial observation, the replicate figure is significantly darker in color than the original figure. Although they both display a yellow-tinted background color, the replicate figure has a dark yellow-orange color, while the original figure has a light, yellow-beige color background. Similarly, both figures contain the three essential images of the interaction between the Sweet Olive tree and the English Ivy. The first photo is taken of the English Ivy strand, the second of the Sweet Olive tree, and the third photo captures both species interacting with one another from a farther distance. All three photos of the replicate figure capture nearly-identical images of the original figure. However, in the replicate photos, the sun appears to be setting, as the sun is setting at a different angle than in the original photos. Additionally, the arrows used on the third photo to signify the two species from the replicate photo are both pointing towards the left direction. To contrast, in the original photo the blue arrow is pointing in the right direction and the red arrow is pointing in the left direction. The text above the actual photos is identical in both figures. However the photos in the replicate figure appear to be significantly smaller in comparison to the original figure.

The two scientific multi-panel figures above resulted in the following observational differences. The replicate figure upon initial observation is significantly darker in color than the original figure. Although they are both contain a yellow background, the replicate figure has a dark yellow, orange color, while the original has a light, yellow-beige color background. Both figures contain three images, the first taken of the identical English Ivy strand, the second of the Sweet Olive tree, and the third of both species together taken from a further distance. All three photos of the replicate figure capture the same angles of the original figure almost exactly. However the replicate photos were taken during the evening, as the sun is setting at a different angle as in the original photos. The arrows used on the third photo from the replicate photo are both horizontal, however facing the left direction, as opposed to in the original photo the blue arrow is pointing in the right direction and the red arrow is pointing in the left direction. The text above the actual photos is identical in both figures. The photos in the replicate figure appear to be smaller in size in proportion to the figure than in the original figure.

The data above compares Drosophila melanogaster growth and development at each gender and life stage at varying concentrations of the growth hormone, ecdysone. According to Figure 1 and Tables 2 and 3, overall, pupae are most abundant during normal conditions (control vial). In table 2 we observed 81 pupae in the control vial, followed by 61 pupae in the 10 µM vial, then 47 pupae in the 1.0 vial, then 25 pupae in the 0.1 vial. This coincides with the data in Figure 1, where pupae exhibit the largest number of flies than any other life stage, with the control vial displaying the largest number of pupae counted. In Figure 2, for the control vial and the 10 µM vial, there is a significantly higher number of females than males. This is also supported by Table 2, where there are 10 females and 3 males for the control, and 2 females and 0 males for the 10 vial. On the other hand, for the 0.1 and 1 concentrations of ecdysone, there are more males than females. In Figure 3, the females overall have a greater length than that of the males throughout all concentrations of ecdysone.

Drosophila melanogaster have been used as a model system for generations as an ideal organism for the study of development, behavior, and genetics due to their short life cycle (allows for larger fly production), ease of culture, and on a molecular level, shares many similar features and pathways with humans. Being able to produce multiple generations and view the different life cycles of the flies allows us to easily observe the effects of hormone concentration upon the growth and development of the organisms. In insects, the two hormones, juvenile hormone and ecdysone (Ponasterone A), control timing of normal molting, and formation of the pupa. (Yamanaka). Ecdysone is is a steroidal prohormone of the major insect molting hormone 20-hydroxyecdysone, one of many hormones which regulate growth in Drosophila. Ecdysone is essential in transforming the body plan of insects from larva to the adult fly by activating the programmed cell death of larval tissues and causing cell shape changes in the imaginal discs during Drosophila metamorphosis. Ecdysone signaling is important in morphogenetic movements that shape the first instar larva.

Multicellular organisms depend on several hormones to regulate their growth and development. Drosophila melanogaster is a small, common house fly most people recognize as the insects that appear out of “thin air” to feast upon rotting fruit or the trash in one’s kitchen. Drosophila melanogaster exhibits complete metamorphism, where the life cycle includes an egg, larval (worm-like) form, pupa and finally emergence as a flying adult. Fruit flies can lay hundreds of eggs during their lifetime. After about a day, a larva emerges from the egg. As it grows, the maggot goes through three instars, which it develops until the pupa is formed. Inside the pupa, larval structures and tissues break down and are reabsorbed, and adult tissues start to develop until the adult fly breaks out of the anterior end of the pupa. Soon the body of the fly becomes more rounded and dark and the wings expand. After ten more hours, the flies are sexually mature and ready to produce another generation.

Chapter 12 of the Sixth Extinction, The Madness Gene, dealt with the various theories that have developed overtime to explain the Neanderthals themselves and also why they disappeared so suddenly. In a larger spectrum, Elizabeth Kolbert addresses the role that humans may have contributed in wiping out the closely related Neanderthals. Hence this chapter shows a bleak portrait of human nature, suggesting that humans are capable of destroying even beings that resemble themselves closely enough to breed with. In a both sad yet fascinating aspect, Kolbert explains that, “before humans finally did in the Neanderthals, they had sex with them. As a result of this interaction, most people today are slightly- up to four percent- Neanderthal” (238). The chapter begins by introducing paleogenetics, in which it is sometimes possible to examine prehistoric remains and find fragments of DNA. Using DNA samples, scientists like Pääbo can reconstruct what long-extinct creatures looked like, and their genome. Pääbo’s goal specifically is to sequence the entire Neanderthal genome, in order to lay out the human and Neanderthal genomes to find where they diverged.

Fish Species First Observations:

Lamprey has long, skinny, small circular mouth with teeth for latching onto other fish (buccal tunnel), gray with black spots, tail, holes on sides, two eyes on sides, posterior dorsal fin, caudal fin, anterior dorsal fin, jaw, nostril, tail.

Dogfish has dorsal fin, second dorsal fin, pectoral fin, snout, caudal fin, nostril, eyes on side, fin spine, gill slits, mouth, teeth, jaw.

Ratfish has gills, first dorsal fin, second dorsal fin, pelvic fin, anal fin, mouth, no teeth, eyes on side, caudal fin, nostril, jaw, pectoral.

White perch has caudal fin, anal fin, lateral line, pelvic fins, pectoral fin, chin barbels, Gill cover, first dorsal fin, second dorsal fin, gills

Sea robin has elongated pectoral fins, large ventral fins, upper jaw/jaw, gills, two short spines, 2 eyes, 10 spines, anal fin, dorsal fins,

Carp has caudal fin, anal fin, pelvic fin, pectoral fin, dorsal fin, adipose fin

Skate has spiracles, snout, eyes on top, pectoral fin, pelvic fin, caudal fin, spine, flat

Stingray is flat, two large pectoral fins, mouth on underside, two eyes on top, gray on top, lighter color on underside, tail, gills, stinger, pelvic fin, claspers, spiracles.

The morphological characters that were most useful were those that were not ancestral traits (that all the fish had), such as teeth, the anal fin, nostrils, tails, and pelvic fin to name a few. These were most useful because they allowed us to put the fish into groups that showed their relation. One morphological character that led us to believe there was an incorrect relationship between certain fish would be the spine. We related the stingray, dogfish and the sea robin together, but not the skate, which was in reality actually a relative of the stingray. The fast evolving gene is better for resolving these taxa. I think this the case because the fast evolving tree properly categorized the lamprey as the outgroup as well as matched the dogfish in the right position.

Observations are based upon the attention and gained information from something using the five senses. They are experienced first hand, and help to reach an inference. An inference is the logical explanation of the observation, or the conclusion drawn based on the evidence. It can be a second hand experience. An instance of using the two is in the scenario with the spike worms and silk worms we received on the first day of this class. When given the small plastic cups, the first thing we did was observe the mysterious object handed to us. We used our senses to see that the object was small and tan in color. We watched the object rear up on its tiny stubby legs and make its way around the edges of the cup. We noticed that one side of the object’s body was slightly darker than the rest of the body. There were several other factors about the object that we were visually able to observe. Had we physically touched the object’s body or utilized our keen sense of smell and hearing, we may have had further observations. Using these specific observations we then began to make conclusions. The big brown eyes on the darker, posterior end of the body had the visible characteristics of eyes, so using this observation and our knowledge of eyes, we could infer that they were eyes. The object was moving independently and displayed characteristics similar to a worm (the body is shaped long and has many legs), therefore we could make the inference that the object is a living organism that is or is related to a worm. Eventually using external resources online and comparing our observations of the object to real photos of worms, we could conclude that it was a spike worm. I have now been keeping the worm and carefully observing it for multiple weeks now. I have observed that the worm now has ceased its movement and grown a brown, hard exterior around the entire body. It appears to be a cocoon, and because I have knowledge that worms can alter their body composition into moths or flies, I can infer that because my worm is in a cocoon now, it is undergoing metamorphosis and will transform into either a moth or fly. I am able to make an inference based upon primary observation and also secondary knowledge.

Observations are based upon using the five senses to pay close attention to something and gain information from. They are experienced first hand, and help to reach an inference. An inference is the logical explanation of the observation, or the conclusion drawn based on evidence and can be a second hand experience. An instance of using the two is in the scenario with the spike worms and silk worms we received on the first day of this class. When given the small plastic cups, the first thing we did was observe the mysterious object handed to us. We used our senses to see that the object was small and tan in color. We watched the object rear up on its tiny stubby legs and make its way around the edges of the cup. We noticed that one side of the object’s body was slightly darker than the rest of the body. There were several other factors about the object that visually we could observe. Had we physically touched the object’s body or smelled it or listened to it, we may have had further observations. Using these specific observations we then began to make conclusions. The big brown eyes on the darker end of the body have the visible characteristics of eyes, so we can infer that they are eyes. The object is moving independently and has the characteristics likewise to a worm, therefore we can make the inference based on appearance that the object is a living organism that is or related to a worm. Eventually using external resources online and comparing our observations of the object we could conclude that it was a spike worm. I have now been keeping the worm and carefully observing it for multiple weeks now. I have observed that the worm now has ceased its movement and grown a brown, harder exterior covering the entire body. It appears to be a cocoon, and because I have knowledge that worms can alter their body composition into moths or flies, I can infer that because my worm is in a cocoon now, it is undergoing metamorphosis and will transform into either a moth or fly. I am able to make an inference based upon primary observation and also secondary knowledge.