Environmental Science
Responses to the environment
What are the 11 ways animals can respond to their environment?: (1) taxis, (2) kinesis, (3) nocturnal & diurnal activity, (4) fight or flight, (5) territorial response, (6) bird songs, (7) bird songs, (8) camouflage, (9) Parent/offspring interactions, (10) Mating displays, (11) pack/flock/herd behavior
To what extent can a plant respond to their environment?: Plant cells can communicate with other cells, and plants can communicate with other plants and animals.
What are some examples of plants responding to their environment?: germination, cell differentiation, flowering, fruit ripening, root growth, branching, abscission, drought, light, and defense against predators.
What are tropisms?What are the main 3?: Growth towards or away from a stimulus, such as light (phototropism), gravity (gravitropism), or touch (thigmotropism), which allows plants to adapt their growth patterns for optimal survival.
What are some additional responses other than tropisms (there are 4)? In addition to tropisms, plants exhibit photoperiodism, where they can sense the length of day and night to regulate flowering. There is also Apical dominance which is where the main central stem of the plant grows more robustly than the side stems, allowing the plant to maximize its height and improve its access to sunlight. Third, there is Abscission which is the process by which plants shed their leaves, flowers, or fruit in response to environmental cues, such as changes in temperature or water availability, to conserve resources and ensure survival. Finally, plants have circadian rhythms which are described as internal biological clocks that regulate various physiological processes in accordance with the day-night cycle, influencing activities such as photosynthesis, hormone production, and flowering times.
Explain the phototropism & gravitropism of roots & shoots: Phototropism refers to the growth of plant shoots towards light, enabling them to maximize photosynthesis, while gravitropism dictates that roots grow downwards in response to gravity, anchoring the plant and accessing water and nutrients in the soil.
Summary: Phototropism = Stem growth in sun, while gravitropism = Root growth due to gravity
In terms of photoperiodism, what is the critical factor that determines flowering in plants?: The critical factor that determines flowering in plants is the specific duration of light and dark periods, commonly referred to as the photoperiod. Different plants have varying requirements for light exposure, and these can be categorized as short-day, long-day, or day-neutral plants, each responding uniquely to the changes in daylight throughout the seasons. If a “Short-day” plant doesn’t get enough sunlight required for them they will not flower, whereas "Long-day" plants require extended light exposure to trigger flowering, and "Day-neutral" plants can flower regardless of day length.
Explain the difference between day –neutral, short-day, and long-day plants?:
Day-neutral plants do not depend on photoperiod and can flower at any time of the year
short-day plants require longer periods of darkness to initiate flowering
long-day plants necessitate extended light exposure to stimulate their blooming process.
What are hormones? How do they work?: Chemical signals produced in one part of an organism that influence another. Effective in very small doses hormones trigger a response at the cellular level due to specific hormone receptor binding.
How are hormones important in plants?: Overall behavior and growth relies on the delicate balance of plant hormones, which regulate various physiological processes including flowering, fruiting, and responses to environmental changes.
Explain how hormones are responsible for cellular change. Briefly explain/review the process of signal transduction.:
Hormones bind to their respective receptors on target cells
A series of biochemical events known as signal transduction pathways are caused.
With this process, there is the activation of secondary messengers, which amplify the signal and facilitate a response, such as changes in gene expression or enzyme activity
Leading to cellular changes that affect the organism's overall function.
Stimulatory Hormones
Auxins:
Promote cell elongation and are essential for growth in plants, influencing processes such as phototropism and gravitropism, and induces cell division in vascular cambium
Inhibitory Hormones
What does Abscisic Acid do? When is it Produced?
Produced during water stress (Which closes the stomata). Prepares for dormancy by inhibiting vaascular cambium and slowing bud growth. Second, it keeps seeds dorman and prevents premature germination, ensuring that they only sprout under optimal environmental conditions.
Describe in detail the experiments of Darwin/Darwin, Boysen/Jensen, and Went. What insights did these experiments provide about phototropism?
The experiments conducted by Darwin and his son Francis demonstrated that plant curvature toward light (phototropism) is influenced by a growth hormone, which they theorized could be produced in the tips of the plants.
Boysen-Jensen built upon this work by using agar blocks to show that the hormone, which he called 'auxin,' could be transmitted from the tip to the rest of the plant, prompting growth on the side that was away from the light.
Went further advanced these findings by isolating and quantifying auxin, proving that unequal distribution of this hormone resulted in differential growth rates on opposite sides of the plant, ultimately leading to the bending towards the light source.
Describe the process of transpiration.: Transpiration is the process through which water vapor is lost primarily through small openings called stomata. This loss of water creates a negative pressure within the plant, which facilitates the upward movement of water and nutrients from the roots through the xylem.
Xylem: A type of vascular tissue responsible for the transport of water and dissolved minerals from the roots to the various parts of the plant, playing a crucial role in maintaining plant hydration and supporting overall physiological function.
The cells of the xylem are made of a network of tubes, like vessels
Plants ONLY get there water from their roots (in the ground)
Stomata:
Like plant nostrils, they open and close to regulate gas exchange, allowing carbon dioxide in and oxygen out.
Mostly in the leaves and each leaf have thousands of them
Any time the leaves open their stomata water evaporates (transpiration)
Each stoma has 2 guard cells that open and close the hole, which respond to environmental conditions such as light, humidity, and carbon dioxide concentration to optimize the plant's water use and gas exchange efficiency.
Guard Cells:
They can change shape, meaning if they are flaccid or turgid, the size of the stoma will either increase or decrease, allowing the plant to regulate its water loss and maintain homeostasis.
The more water = turgid = open, les water = flaccid = closed
The guard cells will pump potassium into their cytoplasm which causes the cell to by hypertonic , leading to an influx of water via osmosis, ultimately resulting in turgor pressure that opens the stomata. Conversely, when potassium ions are actively transported out of the guard cells, the water potential inside the cells increases, causing them to lose water and become flaccid, which subsequently leads to the closure of the stomata.
Phloem: The vascular tissue responsible for transporting sugars and other metabolic products downward from the leaves to other parts of the plant. (all the way to the roots).
Ethylene: inhibits self growth and ripens fruits
Why would the water potential be lower in the leaves then the roots?: Because water is constantly leaving through the stomata, creating a negative pressure that draws water up from the roots through the xylem
What physical and biological factors contribute to it? Why is it a “necessary evil” for plants?:
Physical factors: Higher temperatures increase evaporation rates, while lower humidity reduces moisture in the air, promoting greater water loss from leaves.
Biological factors: The presence of stomata on leaf surfaces, their size and distribution, and the health of the plant's root system play crucial roles in regulating water loss.
Necessary evil: While transpiration is essential for nutrient uptake and cooling of the plant, it also results in significant water loss, which can be detrimental during periods of drought.
Describe the tissues/cells involved in the transport of water in plants.
Explain the processes that enable water to travel from the roots to the leaves of plants. How are the special properties of water involved?
Water travels from the roots to the leaves through several processes:
Roots absorb water from the soil via osmosis, which is driven by the high concentration of minerals in root cells. The pull of water, from the hypotonic soil t the hypertonic roots
As water enters the roots, it generates a positive pressure that pushes water upwards through the xylem.
Transpiration: As water evaporates from the stomata of leaves, it creates a negative pressure that pulls more water upward from the roots, essentially creating a continuous flow.
The special properties of water that facilitate this process include:
Cohesion: Water molecules are attracted to each other, allowing them to form a continuous column in the xylem vessels.
Adhesion: Water molecules stick to the walls of xylem vessels, helping to counteract the force of gravity.
What is the cohesion-tension theory?
The primary tissues involved in the transport of water in plants include xylem and phloem.
The cohesion-tension theory describes this mechanism, positing that the cohesion between water molecules provides the tension necessary to pull water upwards against gravity, thus allowing efficient transport from roots to leaves.
Explain how/why temperature, humidity, air currents, stomata and K+ affect the rate of transpiration.
What is the role of water in the opening and closing of the stomata?
Discuss how temperature, CO2 concentration, abscisic acid and light affect the concentration of K+ and, therefore, the opening and closing of the stomata.
Briefly describe how plants respond to the following: O2 deprivation, high salt, heat, cold, herbivores, pathogens
Scroll down for environmental science…..
Environmental Science
Give examples of biotic and abiotic factors in the environment. What is the difference between a habitat and a niche?
Biotic factors: Plants, animals, fungi, bacteria (living)
Abiotic factors: Water, sunlight, temperature (non-living)
A habitat refers to the natural environment where an organism lives, while a niche describes the role an organism plays in that environment, including how it gets its resources and interacts with other species.
Habitat: the location
Niche: all aspects of an organisms existence? (including where it is in the chain)
Differentiate between a species/community/population/ecosystem/biosphere/biome. Give examples of biomes. Where would a biome fit into the diagram below?
Food chains/food webs/energy pyramids
     keystone species   Â
   food webs
Use the diagrams below to differentiate between a food chain and food web.
Producers: at the bottom of the ecosystem, the only ones in the ecosystem that can photosynthesize (including some bacteria! Autotropich)
— Heterotrophs—-
Consumer levels:
Primary
Secondary
Tertiary
Quaternary
(Sometimes more but usually stops at quaternary)
Decomposers: The things that eat dead things
IN A CHART! YOU MUST ALWAYS HAVE ARROWS FROM EVERY ANIMAL TO THE DECOMPOSER INDICATE THE FLOW OF ENERGY AND NUTRIENTS THROUGH THE FOOD WEB. (INCLUDING PLANT!)
Plants âž” Decomposers
Herbivores âž” Decomposers
Carnivores âž” Decomposers
Omnivores âž” Decomposers
Scavengers: Eat dead stuff but don’t recycle it
Arrows: indicate the flow of energy and matter through the different trophic levels in an ecosystem. These levels represent the hierarchy of organisms in a food chain, starting from producers at the base, followed by primary, secondary, and tertiary consumers, culminating in apex predators.
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Using the diagram below, identify producers, primary consumers, secondary consumers, tertiary consumers, and decomposers. What is the significance of the arrows in food webs and chains? Add decomposers to both the web & the chain below. What is a keystone species?
Diagram a terrestrial food chain. Be sure to identify all of the parts as given above.
What are trophic levels? How does biomass relate to trophic levels? Describe the energy change that takes place between trophic levels (the 10% rule):
Trophic levels refer to the different positions that organisms occupy in a food web or chain, categorized as producers, primary consumers, secondary consumers, tertiary consumers, and decomposers. Biomass decreases at each successive trophic level due to energy loss, primarily through metabolic processes, resulting in only about 10% of the energy being transferred to the next level. This energy change illustrates the inefficiency of energy transfer in ecosystems, where the majority of energy is used for growth, reproduction, and maintenance by organisms within a trophic level, highlighting the importance of energy flow in ecological studies.
Diagram an energy pyramid. Why are plants at the bottom of all energy pyramids? Why does the number of organisms decrease as you move up the pyramid (think energy).
The largest population→ producers (90% used)
The second → Primary (90% of the 10% = 9%)
The third → Secondary (8.1%
And so on…
Diagram an energy pyramid. Why are plants at the bottom of all energy pyramids? Why does the number of organisms decrease as you move up the pyramid (think energy).
Use the diagram to explain the concept of biomagnification. biomagnification
Biomagnification: a concentration of a substance increases as it goes up the food chain/web/pyramid
Use the provided diagrams and/or websites to review each nutrient cycle.For each cycle, you should be able to describe the organisms and processes that move the nutrient around the ecosystem, how humans are affecting the cycle.Â
water cycle: The water cycle involves processes such as evaporation, condensation, precipitation, and infiltration, with key organisms including plants, which absorb water, and animals, which return water to the atmosphere through respiration.
What are the steps of the water cycle?
Evaporation: Water from oceans, rivers, and lakes is heated by the sun and transforms into vapor, entering the atmosphere.
Condensation: Water vapor cools as it rises, condensing into tiny droplets to form clouds.
Precipitation: When the droplets combine and grow heavy, they fall back to Earth as rain, snow, sleet, or hail.
Infiltration: Some of this water seeps into the ground to replenish aquifers, while the rest flows into bodies of water.
Transpiration: Plants also contribute by absorbing groundwater and releasing water vapor back into the atmosphere through their leaves.
carbon cycle: This process describes the movement of carbon through the Earth's systems, including the atmosphere, hydrosphere, lithosphere, and biosphere, as it is absorbed and released by living organisms, soil, oceans, and the atmosphere.
what are the steps of the carbon cycle?
The steps of the carbon cycle include:
Photosynthesis: Plants absorb carbon dioxide from the atmosphere and convert it into organic matter.
Respiration: Living organisms release carbon dioxide back into the atmosphere through metabolic processes.
Decomposition: When organisms die, decomposers break down their organic material, releasing carbon back into the soil and atmosphere.
Combustion: The burning of fossil fuels and biomass releases stored carbon into the atmosphere as carbon dioxide.
Ocean Uptake: The oceans absorb carbon dioxide from the atmosphere, which can be used by marine organisms for photosynthesis or stored in deep waters.
What are the steps of the Nitrogen cycle? The steps of the Nitrogen cycle include:
Fixation: Atmospheric nitrogen is converted into ammonia by nitrogen-fixing bacteria.
Nitrification: Ammonia is oxidized to nitrites and then to nitrates by nitrifying bacteria.
Assimilation: Plants absorb nitrates from the soil and use them to produce proteins and nucleic acids.
Ammonification: Decomposers break down organic matter, returning ammonia to the soil.
Denitrification: Denitrifying bacteria convert nitrates back into atmospheric nitrogen, completing the cycle.
Eutrophication Eutrophication AnimationÂ
Population Ecology
stages of the demographic transition
What is exponential growth? Diagram a curve that results from exponential growth. Why is this curve referred to as a J-shaped curve?
What is carrying capacity? How does this change the above curve? (S-shaped curve)
Describe 2 density-dependent limiting factors, and 2 density –independent limiting factors.
Use the chart below to review the differences between r-strategists & K-strategists. Give examples of organisms for each type of strategist.
Describe 4 factors that have contributed to the human population growth since 8000 BC.
What is demography? What information can be obtained from histograms?
Use the histograms to answer the questions that follow.
In the DRC, what % of the population are 25-29 year old males?
In Germany, what % of the population is 10-14 year old females?
Describe the difference in the shapes of the histograms for each country above.
What is going to happen to the DRC population over the next 10 years?
List 5 environmental problems that are a result of overpopulation.
How does population growth differ in developed and developing countries?
Use the diagram to explain the 4 stages of demographic transition. What are some of the reasons that the population stabilizes in developed countries
Succession
What is succession? What is a climax community?
Create a chart to compare & contrast primary & secondary succession in terms of the following: pioneer species, length of time, presence/development of soil, circumstances under which each will occur
Biomes
http://www.blueplanetbiomes.org/
https://ucmp.berkeley.edu/exhibits/biomes/index.php
Create a chart that includes the following land biomes: desert, tundra, prairie, savanna, coniferous forest, rain forest, and deciduous forest. For each of these, include the following; avg. temp. and rainfall, a unique factor/characteristic, 2 examples of plant adaptations and 2 examples of animal adaptations specific for that particular biome.
List the 2 types of freshwater ecosystems, and use a maximum of 3 sentences (YOUR OWN WORDS) to distinguish between them.
In what zone of the ocean would you expect to find the greatest biodiversity? Why?
How are wetlands and estuaries similar? Why are these so ecologically important?
Environmental Issues
     Waste Management
acid rain       Â
   global warming      Â
biodiversity  Â
What causes acid precipitation?
List 2 types of damage from acid precipitation.
Why is the ozone layer important to living organisms?
List the major greenhouse gasses. Why are these gasses important to life on earth?
What is the relationship between greenhouse gasses and global warming?
What is biodiversity? What are invasive species? How are they a threat to biodiversity?
What 4 major factors are contributing to the loss of biodiversity?
List three reasons that biodiversity is important.
Explain the concept of sustainability (general definition). Give 2 examples of sustainable practices, either on a large scale, or in your daily life.
Article:
Can plants tell time?
different flowers bloom at different times (the different types, long-days, short-days)
Plants can tell the hours of uninterrupted darkness
Long-days: Grow when the days are longer (summer)
short-days: Grows when the days are on the shorter end (fall + spring) They typically require less than 12 hours of light each day for optimal flowering.
Light sensitive proteins: known as Phytochromes, these proteins play a crucial role in the plant's ability to sense and react to the photoperiod, influencing flowering time and other developmental processes.
There are two forms, one that detects long red light and the other detects short red light.
Class Questions:
What factors return water to the atmosphere?:
Evaporation: The process by which water is transformed from liquid to vapor, primarily from surfaces of water bodies, soil, and plants.
Transpiration: The release of water vapor from the stomata of plants during photosynthesis, contributing significantly to the moisture in the atmosphere. Water evaporates from plants at a very very high rate.
Sublimation: The direct transition of water from solid (ice or snow) to gas without passing through the liquid phase.
Condensation: The process by which water vapor cools and transforms back into liquid droplets, forming clouds and eventually leading to precipitation.
Precipitation: The process by which condensed water vapor falls back to Earth in various forms, including rain, snow, sleet, or hail, replenishing surface water and groundwater sources.
What is osmosis?: Osmosis is the diffusion/movement of water molecules through a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration, aiming to equalize solute concentrations on both sides.
What is water potential? How does it influence osmosis?: Water potential is a measure of the potential energy in water, which influences the movement of water across cell membranes through osmosis by determining the direction in which water will flow, either into or out of the cell.
Water potential = Water concentration
Water will move from where there is more water to where there is less
What do the terms hypertonic and hypotonic mean?: Hypertonic refers to a solution that has a higher concentration of solutes compared to another solution, leading to water moving out of a cell, while hypotonic indicates a solution with a lower concentration of solutes, causing water to move into a cell.
Remember that the status of the hypertonic/hypotonic depends on SOLUTE concentration NOT WATER concentration
How does the concentration?: The concentration gradient influence the movement of water, as water travels from areas of high water potential (lower solute concentration) to areas of low water potential (higher solute concentration), affecting cell volume and pressure.
Vernalization: the process by which certain plants require a period of cold exposure to trigger flowering, influencing their growth cycle and seasonal adaptations.
How does air current effect transpiration?: Air currents can enhance transpiration rates by increasing the evaporation of water from leaf surfaces, thus promoting a greater gradient for water movement from the soil through the plant and ultimately into the atmosphere.
How does Humidity effect transpiration?: High humidity levels can reduce the rate of transpiration by decreasing the water vapor gradient between the inside of the leaf and the surrounding air, leading to less evaporation of water from the leaf surfaces.
How does light impact transpiration?: Light plays a crucial role in regulating transpiration rates, as increased light intensity enhances the photosynthetic activity in plants, which in turn raises the temperature of the leaf surfaces and facilitates greater evaporation of water.
What factors allow for water movement in plants?: Several factors facilitate water movement in plants, including root pressure, capillary action within plant tissues, the cohesive properties of water molecules, and the transpiration pull generated by the loss of water vapor during transpiration.