videos from lessons Flashcards
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Why is nitrogen removal important in wastewater treatment?
Excess nitrogen can lead to eutrophication, causing algal blooms and oxygen depletion in water bodies, which harms aquatic life.
What are the primary forms of nitrogen found in wastewater?
Ammonia (NH₃), nitrate (NO₃⁻), and nitrite (NO₂⁻)
What is nitrification in the context of wastewater treatment?
A biological process where ammonia is oxidized to nitrite and then to nitrate by nitrifying bacteria.
What is denitrification in wastewater treatment?
A biological process where nitrate is reduced to nitrogen gas (N₂) by denitrifying bacteria under anoxic conditions, removing nitrogen from the water.
Why is controlling oxygen levels important in nitrogen removal processes?
Oxygen levels determine whether nitrification (requires oxygen) or denitrification (requires low or no oxygen) occurs, both essential for effective nitrogen removal.
What is forensic entomology?
The study of insects and arthropods in legal investigations, particularly to estimate time of death and other details in criminal cases
Which insects are typically the first to arrive at a decomposing body?
Blow flies (Calliphoridae) are usually the first, laying eggs that hatch into maggots feeding on the soft tissues.
How do forensic entomologists estimate the post-mortem interval (PMI)?
By analyzing the development stages of insects (especially maggots) found on the body and correlating them with known growth rates under specific environmental conditions.
What is the significance of insect succession in decomposition?
Different insect species colonize a body at various decomposition stages; understanding this sequence helps determine the timeline of death
What role do beetles play in the decomposition process?
Beetles, such as dermestids, arrive later in decomposition to feed on tougher tissues like skin and ligaments.
How can environmental factors affect insect activity on decomposing bodies?
emperature, humidity, and location (e.g., buried vs. exposed) influence insect colonization patterns and development rates.
Why are body farms important in forensic entomology?
They provide controlled environments to study human decomposition and insect activity, enhancing the accuracy of PMI estimations
Can insects provide information beyond time of death?
es, they can indicate if a body was moved, presence of drugs or toxins, and even help identify wounds or trauma
What is the role of maggot development in forensic investigations?
Analyzing maggot size and development stages helps estimate the time since death, considering known growth timelines under specific conditions
How do forensic entomologists collect insect evidence at a crime scene?
By gathering insects at various life stages from the body and surrounding area, preserving them for laboratory analysis to determine PMI and other forensic details.
species-area rule that Wilson found
describes how the number of species increases with the area of a habitat.
Definition:
The species-area rule states that larger areas tend to contain more species than smaller ones. Mathematically, it is often expressed as:
S=cA^z
s= number of species
A= area
c and z constants, vary depending on habitats and organisms
key findings:
* On islands or isolated habitats, as area increases, so does the number of species, but at a decreasing rate (the curve levels off).
* Habitat fragmentation (breaking up large areas into smaller ones) leads to species loss, because small areas can’t support as many species.
* Wilson used this rule to predict extinction rates in fragmented ecosystems, especially tropical rainforests.
* He emphasized that protecting large, continuous habitats is critical to preserving biodiversity.
how did the eruption of Mount Krakatoa provide evidence for Wilson’s rule?
🌋 What Happened:
* The eruption completely sterilized the island of Krakatoa and surrounding islands in Indonesia — all plant and animal life was wiped out.
* Over the following decades, scientists observed how life returned to the island — this natural recolonization provided a unique chance to study how ecosystems form from scratch.
🧠 How It Supported Wilson’s Rule:
1. Species Accumulation Over Time
As time passed, scientists recorded a steady increase in the number of species on Krakatoa.
This matched Wilson’s prediction that species richness increases with area and time, up to an equilibrium.
2. Distance from Mainland Matters
Krakatoa and nearby islands are relatively close to the mainland (Java and Sumatra).
Wilson’s island biogeography theory said islands closer to a source of species (mainland) would recolonize faster — and that was exactly what happened.
3. Species Turnover
Some species that first colonized the island later disappeared, replaced by others better suited to the maturing environment.
This dynamic matched Wilson’s idea that species composition changes over time, even if the total number of species stabilizes.
How did the Florida Key experiment provide evidence for Wilson’s rule?
🧪 What Was the Florida Keys Experiment?
Wilson and Simberloff:
* Selected small mangrove islands in the Florida Keys.
* Fumigated several of them with insecticide to completely wipe out the existing insect populations (no other organisms were significantly affected).
* Carefully monitored how species recolonized the islands over time.
🧠 What They Found (and How It Supported Wilson’s Rule):
1. Recolonization Happened Predictably
* Within a year, many insect species had returned.
* The number of species rose quickly at first, then leveled off—showing a predictable species accumulation curve.
* This directly confirmed the species-area rule: species richness is a function of island size and distance from a source population.
- Equilibrium Theory in Action
* Each island reached a relatively stable number of species, even though the actual species identities varied over time (some species went extinct and were replaced).
* This validated the idea of a “dynamic equilibrium”: the number of species stays stable, but individual species come and go. - Size and Distance Affected Recovery
* Islands closer to the mainland recolonized faster and reached higher species diversity than more distant islands.
* This supported the prediction that immigration rates are higher on islands closer to the source of colonizers.
What was found in the Amazon experiment? What was the importance of these findings for conservation biology?
🌳 What Was the Amazon Fragmentation Experiment?
* Scientists, including Thomas Lovejoy, worked with the Brazilian government to create experimental forest fragments in the Amazon rainforest of different sizes:
* 1 hectare (ha)
* 10 hectares
* 100 hectares These were isolated by clearing the surrounding forest, simulating habitat fragmentation caused by human activity (e.g., farming, roads, deforestation). Researchers then monitored biodiversity changes over time.
🔍 What Was Found?
1. Species Richness Declined with Fragment Size
* Smaller fragments lost species more quickly than larger ones.
* Especially vulnerable were large mammals, birds, and forest interior species that require large, undisturbed ranges.
- Edge Effects Were Strong
* The borders of forest fragments were hotter, drier, windier, and more prone to invasive species.
* These “edge effects” penetrated deep into small fragments, making them less hospitable for many native species. - Isolation Reduced Recolonization
* Isolated fragments were less likely to be recolonized by species from nearby continuous forests.
* Over time, even if the number of species temporarily stabilized, biodiversity continued to erode due to isolation. - Biodiversity Erosion Takes Time
* Some species persisted for a while after fragmentation but declined gradually — showing a “relaxation” effect (delayed extinction).
Why is biodiversity higher near the equator?
The tropics have stable climates, abundant energy from sunlight, and high productivity, supporting more species
How does the Earth’s surface area relate to species distribution?
Tropical regions cover about 40% of Earth’s surface, providing more space for diverse habitats and species
What role does climate stability play in species diversity?
Stable climates in the tropics allow species to specialize without the risk of sudden environmental changes.
How does specialization affect biodiversity in the tropics?
Intense competition and stable conditions lead species to specialize in narrow niches, increasing diversity.
What is the “cradle and museum” concept in biodiversity?
he tropics act as a “cradle” by generating new species and as a “museum” by preserving existing ones due to low extinction rates.
