Bio Midterm 3

what is GPP?

GPP (Gross Primary Production) is the total amount of carbon dioxide that is captured by photosynthesis in a given area and time. It represents the primary energy input into an ecosystem. total energy

What is NPP?

NPP is all the carbon plants store and don’t respire out;

The energy available to ecosystem

GPP-Respiration= NPP

The greater than NPP, the more species and individuals

10% of energy is lost at each trophic level

What is NEP?

NEP is all the carbon stored in the ecosystem’s biomass that isn’t respired out.

Explain the difference between abiotic and biotic factors in an ecosystem and provide examples of how these factors can affect the communities present. LO 26.1

Biotic=Anything alive or once alive (interactions w each other like mutualism, predation, competition, etc)

Abiotic= Physical environment (non-living)

Factors can affect communities present because Abiotic factors determine where organisms can live, and biotic interactions determine where they do live.

Create a diagram explaining the nested relationships among populations, species, communities, and ecosystems. LO 26.2

A diagram illustrating that organisms are one single thing that focuses on individual behavior and survival decisions,

populations consist of individuals of the same species at same time in same place (focus is on pop. increases and decreases),

species are all pops. of a species (evolution, adaptations),

communities are composed of multiple species interacting in the same area (interactions btw species), and

ecosystems encompass communities along with their abiotic environments (environmental interactions with community. Energy flow and nutrients).

Describe the major events in the global cycling of water, carbon, and nitrogen cycles. LO 27.1

The major events in the global cycling of water, carbon, and nitrogen include processes such as evaporation, precipitation, photosynthesis, respiration, and nitrogen fixation. These cycles facilitate the movement and transformation of these essential elements among the atmosphere, biosphere, hydrosphere, and geosphere. Additionally, human activities such as deforestation and fossil fuel combustion significantly impact these cycles, altering their natural balance and contributing to climate change.

Predict the consequences of changes in primary production due to perturbations such as drought, fire, flood, extreme temperatures, or nutrient influx or loss. LO 27.2

Changes in primary production can lead to alterations in ecosystem dynamics, affecting species diversity and nutrient cycling. For example, a decrease in primary production due to drought may reduce food availability for herbivores, impacting the entire food web.

Interpret effects of modifying variables based on computational models of population dynamics. LO 31.5

This involves analyzing how changes in factors such as birth rates, death rates, and migration affect population stability and growth in various environments.

The carbon cycle

CO2 is in the air and then plants, algae, and some bacteria take in the CO2 and use sunlight to convert it into glucose.

Carbon moves from the air to living organisms through carbon fixation, where carbon becomes part of carbohydrates, proteins, and lipids.

What does burning fossil fuels do about carbon?

It releases CO2 quickly, so we're releasing carbon faster than it's stored

How does carbon flow?

Carbon flows through trophic levels like herbivores eat plants they get carbon carnivores, eat, herbivores state carbon car

What does decomposition do about carbon??

Dead organisms decompose so they breakdown organic matter and returned CO2 to the atmosphere

What is a carbon sink?

Some carbon get buried and becomes coal, oil, or a natural gas. This is called a carbon sink.

What is biomass?

The stored carbon = biomass

What does cellular respiration do in the carbon cycle?

All organisms do cellular respiration so the carbon goes from biomass back to carbon dioxide in the atmosphere

What does too much CO2 do?

It is a strong greenhouse gas, so at least to climate change, temperature rise, and ecosystem disruption.

What is the nitrogen cycle?

The atmosphere is 78% nitrogen gas, but most organisms cannot use nitrogen gas directly because it is so strong (triple bond) and heart to break

What is nitrogen fixation?

Converting nitrogen gas N2 to ammonia NH3.

Certain bacteria in archaea, do it.

they use special enzymes to break the end two and add hydrogen to create NH3

Why does ammonia (NH3) matter?

Because it can turn into ammonium and nitrate, which can be absorbed by plants and used to make amino acids (protein) or nucleotides (DNA/RNA)

Regarding the nitrogen cycle, does bacteria do everything?

They do nitrogen fixation(N2 to NH3)

Nitrification(NH3 to NO3-)

Dentrification (NO3- to N2)

Without bacteria, there is no usable nitrogen, there is no proteins, there is no life

What happens when humans add nitrogen using fertilizer?

Humans artificially fix a nitrogen using the industry

It increases plant growth, but also runoff into water (algal blooms) and oxygen depletion(fish die)

1) Water cycle evaporation

Water from oceans, lakes, rivers, soil sun heats the water, and turns it into water vapor.

Driven by solar energy

2) Transpiration (plants release water)

• Plants absorb water through roots

• Release it from leaves as vapor

👉 Evaporation + transpiration = evapotranspiration

🔹 3. Condensation (gas → liquid)

• Water vapor rises into cooler atmosphere

• Cools → forms tiny droplets

👉 This creates:

• Clouds ☁

• Fog

🔹 4. Precipitation

• Water falls back to Earth as:

  • rain 🌧

  • snow ❄

  • sleet/hail

👉 This returns water to ecosystems

5. Runoff + Infiltration

After precipitation:

Runoff:

• Water flows over land → rivers → ocean

Infiltration:

• Water soaks into soil → groundwater

How is water and NPP related?

🌱 Water controls NPP

• Plants need water for photosynthesis

• Low water → low NPP (deserts)

• High water → high NPP (rainforests)

How does water shape biomes?

• Amount + pattern of precipitation determines:

  • forests

  • grasslands

  • deserts

What are climate connections?

• Water cycle affects:

  • temperature

  • humidity

  • weather patterns

What are some human impacts?

• Climate change → alters:

  • evaporation rates

  • rainfall patterns

• Can cause:

  • droughts

  • floods of operation precipitation, evaporation condensation precipitation

Population Growth Exponential:

• unlimited growth

• equation:
  N_t = N_0 y^t

• N0=starting pop.

• t=time

• y=growth rate

• Population growth that occurs when resources are abundant, new habittat (no competition, after disaster (low pop.), allowing for rapid increase over time, typically shown as a J-shaped curve.

This isn't realistic long-term because the resources are limited

What is richness?

Richness refers to the number of different species present in a specific area or ecosystem, indicating biodiversity. Higher richness usually contributes to greater ecosystem stability and resilience.

What is diversity?

Diversity refers to the variety of species, genetic variation, and ecosystem types within a given area, contributing to the health and functionality of ecological systems.

What are the threats to biodiversity?

Threats to biodiversity include habitat destruction, climate change, fragmentation, pollution, invasive species, and overexploitation of resources. These factors can lead to species extinction and loss of ecosystem services.

The more about diversity, the more stable and productive the ecosystem is.

What are some species interactions?

Species interactions include predation(one benefits), competition (both harmed), mutualism(both benefit),, and parasitism(one harmed), all of which shape community dynamics and influence ecological balance.

What is a trophic cascade?

A trophic cascade is an ecological phenomenon where changes in the population of one species (often a predator) ripple through the food web, affecting multiple levels of the ecosystem and leading to significant impacts on community structure and dynamics.

What is a keystone species?

A keystone species is one that has a disproportionately large impact on its ecosystem relative to its abundance. The removal or decline of a keystone species can lead to significant changes in the community structure and ecosystem function.

What are density dependent factors?

Density-dependent factors include resources competition and predation and disease, which become more intense as population density increases, affecting population growth and survival. More individuals, the stronger the effect.

What are limiting factors?

Limiting factors affect population stability. while independent factors are natural disasters. These are environmental conditions that restrict the growth, abundance, or distribution of an organism or population. They can include availability of resources like food and water, environmental conditions, and weather. Affects population, no matter what size.

What is logistic growth?

Logistic growth is a model of population growth characterized by an initial exponential increase, followed by a slowdown as the population reaches its carrying capacity(K), resulting in an S-shaped curve.

It is limited by food, water, disease, predation,etc.

What is carrying capacity?(K)

It is the maximum population size environment can support

Birth rate= death rate

Population stabilizes

Plateau

How are invasive species?

Invasive species are organisms that are introduced into new environments where they are not native, often disrupting local ecosystems and outcompeting native species for resources. They can cause significant ecological and economic harm.

They start exponential than hit limit turns logistic

How do human impacts population?

Can increase or decrease the carrying capacity

Deforestation decreases K

Conservation increases K

How does disease affect population?

If there's a more dense population it's spread faster

What are the effects of deforestation?

CO2 increases.

NPP decreases

soil erosion increases.

Water retention decreases 

the food's collapse.

What does habitat fragmentation do??

Split ecosystems into pieces

Gene flow decreases

Biodiversity decrease

Edge effects increases which is the alteration of conditions at the boundaries of fragments.

which can lead to increased competition, predation or invasion of non-native species.

What is evolution?

Genetic change across generations

What is acclamation?

Individual adjustment