Spheres and Cycles
What is the process through which water moves from the atmosphere to the hydrosphere and lithosphere/geosphere?
Precipitation
Write out the chemical equation that displays how producers create glucose
Water + Carbon Dioxide + sunlight ---> Glucose + oxygen
A group of organisms is considered a species when they can only ___________ with members of that group
Create fertile offspring/reproduce
What is an allele? What is the allele frequency for the offspring when one parent is Aa and one parent is aa?
An allele is a version of a gene
50% Aa
50% aa
Name the system that connects to all other systems AND the main organ of this system
circulatory system; the heart
How does carbon move from the atmosphere directly into the hydrospehere?
Ocean acidification/carbonic acid/carbon moves into the water and reacts with H2O to make acid
The biomass of apex predators is always significantly lower than the biomass of producers. Explain why this is the case.
Producers are at the bottom of the trophic pyramid and apex predators are at the top; only 10% of energy moves up each trophic level, so there is less energy available for apex predators, therefore there is less biomass
Hermit crabs will often pick up and carry sea anemones on their backs. This is a form of mutualism, since both benefit - the crab gets protection from predators, and the anemone gets to be moved around and access new food sources.
Explain how this behavioral adaptation in the crabs is related to natural selection and evolution.
Crabs who had the behavioral adaptation survived and reproduced more often than crabs who did not have the adaptation, therefore the behavior was passed down to future generations
The first step of gene expression takes place in the nucleus of the cell. Name the process, and molecule it creates, and explain WHY this process is necessary for gene expression
Transcription
Makes RNA
mRNA is able to leave the nucleus, whereas DNA must always remain in the nucleus. mRNA is able to go to the ribosome for the next step of gene expression
Explain one way that the endocrine system and the digestive system work together to maintain homeostasis
Insulin is needed to control blood glucose levels after food is digested
The burning of fossil fuels releases carbon into the atmosphere. Name 2 ways that this increase in carbon can impact the environment on Earth
-increased temperatures due to greenhouse gas effect
-ocean acidification
-increased CO2 available for photosynthesis
Ecologists work hard to control invasive species such as the spotted lantern fly. Explain WHY invasive species are so harmful ecologically.
Invasive species have no natural predators, which means they can reproduce very quickly and end up killing off local species
A geneticist has noticed that human populations that historically domesticated cattle have a much higher incidence of lactase persistence than in human populations that historically relied mostly on hunting and gathering. Explain how natural selection led to the development of lactase persistence in the populations that domesticated cattle.
In populations with domesticated cattle, milk and milk products would have been widely available, and people who could eat dairy into adulthood would have access to more calories, therefore giving them a better chance of surviving and reproducing.
Hunter gatherers would not have had access to milk after infancy, so lactase persistence was not a useful trait
What is the second step of gene expression? Name the step and the molecule that is produced; then, explain why this step is necessary to gene expression
Translation
Amino acid sequence/protein
Proteins are needed as enzymes, hormones, and structural components of the body
Explain how the digestive system, respiratory system, and circulatory system work together to maintain homeostasis
Digestion gives you glucose
Respiration gives you oxygen to do cellular respiration with the glucose
Circulatory system moves the glucose and oxygen to where it is needed
All multicellular organisms on Earth need oxygen in order to survive. Write the chemical equation that displays WHY oxygen is necessary for bodily functions.
O2 + glucose ---> ATP + H2O + CO2
Charles Darwin noticed that finches on the Galapagos islands were all very similar to each other anatomically, except for their beaks, which varied widely across different islands. Explain, using natural selection, WHY birds on different islands had different beak shapes
Larger, tougher food = larger beaks are more likely to survive and reproduce = smaller beaked birds died = over time, there were only birds with large beaks
Same for islands with smaller food sources but in reverse
Scientists have noticed an increase in antibiotic resistance in recent decades. In an effort to combat this, they have urged doctors and stress to patients that patients MUST take their full course of antibiotics, even if they feel better after only a few days. Explain, using natural selection, WHY taking the full course of antibiotics is necessary to prevent bacteria from becoming resistant to antibiotics?
If people take only a partial dose of antibiotics, then only the weakest bacteria are killed off, and the strongest are left alive (the ones with resistance)
Natural selection means that those strong bacterial with resistance will survive and reproduce
Then, when the next person catches the bacteria, the antibiotics will not work since ALL of the bacteria are now resistant
A patient is found to have Type 2 diabetes that has been caused by DNA methylation on the gene that codes for insulin. How does methylation stop gene expression, and why does a lack of insulin cause diabetes?
Methylation binds to the DNA and does not allow transcription to occur, so translation cannot occur, so the protein (insulin) cannot be made.
Lack of insulin causes diabetes because blood sugar cannot be controlled
A patient comes into the ER with a fever of 104 degrees and strong cough. What system caused these symptoms, and how do these symptoms try to bring the body back to homeostasis?
Immune system
Coughing = ejecting bacteria/virus/etc from the body
Fever = temperature raises to kill bacteria
Permafrost refers to parts of the geosphere that are permanently frozen. Due to climate change, some of these areas are thawing, meaning that the soil, plant matter, and animal matter that have been frozen for thousands of years are thawing out. This allows bacteria and fungi to use this matter. How does thawing permafrost contribute to an increase in carbon in the atmosphere?
As plant and animal matter thaw out, decomposers such as bacteria and fungi decompose the previously frozen plant and animal matter. As they decompose it, they release the stored carbon as CO2 into the atmosphere through cellular respiration.
Wetlands have very absorbent soil, which allows them to hold on to excess water from rain and flooding. They are also important habitats for fish, migrating birds, and various plant species. However, many wetlands have been paved over to make way for buildings and roads. Explain 3 possible consequences of paving over wetlands.
-habitat loss for animals
-less room for producers = less food for herbivores
-loss of habitat for migration
-loss of flood protection
Malaria is a deadly disease caused by Plasmodium vivax, a microscopic parasite that lives in red blood cells. Some human populations that have historically lived in places with high rates of malaria have a genetic condition called sickle cell anemia. This genetic condition causes the red blood cells to be shaped like small crescents instead of being large, rounded cells. Explain how natural selection led to the prevalence of sickle cell anemia in certain communities
Plasmodium vivax lives in RBCs. If the RBCs are too small, PV cannot live inside of them. So, people with sickle cell anemia did not get malaria and were able to survive and reproduce and pass on their traits. People who had ordinary RBCs caught malaria and died. Over time, most of the population had sickle cell due to natural selection
When an egg cell is fertilized by a sperm cell, a zygote forms. Explain how changes in gene expression allows the zygote to go from a single-celled organism to an infant within 9 months. Make sure to discuss cell division and how different genes are expressed.
The zygote undergoes mitosis to get bigger. Then differentiation happens, when genes are switched on and off in different cells to create specific cells types and specific proteins (i.e. certain sections of the DNA are activated to make lungs, skin, eyes, etc)
After a car accident, a patient comes to the ER with internal bleeding, meaning that blood is leaving the veins and arteries and is instead pooling in body cavities. Explain why internal bleeding results in a patient being unable to maintain homeostasis? Make sure to include cellular processes in your answer
The blood is leaving the veins, meaning that it cannot be returned to the heart, and it is leaving the arteries, meaning that it cannot be delivered to where it needs to go. Since blood delivers oxygen and glucose throughout the body, cellular respiration is greatly reduced when there is internal bleeding