Essential
knowledge 2.D.1: All biological systems from cells and organisms to populations,
communities and ecosystems are affected by complex biotic and abiotic
interactions involving exchange of matter and free energy.
1.Provide examples of how biotic and abiotic factors affect
organism behavior, community interactions, and ecosystem structure. Utilize the
following examples in your responses:
○ Water availability: water is
critical to the survival of all cells, as it is a universal solvent and is used
in a number of cellular processes. If there is competition for water than many
organisms are likely to die.
○ Sunlight: In order to survive,
all photosynthetic autotrophs need the energy sunlight provides to make food
and survive. Other organisms who eat these producers rely on that sunlight as
well. For example, if in a dry area there is one oasis, most of the animals on
the plains will move there to drink.
○ Symbiosis (mutualism,
commensalism, parasitism)
- Mutualism: A situation between two organisms in which both benefit. An
example would be a clown fish and anemone. The clownfish is protected by the
anemone and the anemone is in turn cleaned by the fish.
- Commensalism: an interaction between two species that benefits one but
doesn’t helps or harms the other. An example is the flocks of birds that hang
around buffalo and cattle. The buffalo aren’t hurt but the birds get protection
from predators.
- Parasitism: A relationship
between two organisms in which one benefits (the parasite) and one is hurt (the
host).
○ Predator–prey relationships: A
situation between two species where their numbers directly affect the others
population density. For example, the Canadian Lynx only eats snowshoe hare. If
the Snowshoe Hare population drops, so does the Lynx. If the hare population
rises then so does the Lynx.
○ Water and nutrient availability,
temperature, salinity, pH:
- Temperature: Can affect the rate
of cellular processes, what kinds of plants and animals that live in the area
and the amount of water available to said animals and plants.
- Nutrient availability: Animals
and plants alike need nutrients. These nutrients come from the earth and air
for plants and are transferred from plants to consumers and so on. If these nutrients
become too sparse, the animals and plants will become vitamin deficient and
die. IF there is too much, like for instance phosphorous in waters, plants can
and will grow too much and choke out the other animals (i.e prevent sunlight
from filtering through and as the plants cant get light they cant
photosynthesize and put O2 into the water).
- Salinity: Many plants and animals
can not handle excessive levels of salt water. It dries them out and kills
them. Other organisms who have evolved to have an environment with high
salinity cannot survive without it.
- pH: Many organisms need a
specific pH, especially when conducting cellular processes. Digestion, for
example, need a more acidic environment so foods can be broken down.
○ Availability of nesting materials
and sites: Overcrowding in certain nesting areas can cause a lack of nesting
materials and sites which can result in birds not being able to nest or chicks
being more likely to fall from nests.
○ Food chains and food webs: These
show how all the organisms in the ecosystem are linked and keep one another in
balance.
○ Species diversity: This is all
the different species of organisms in an environment. It ranges from plants to
mammals to birds, lizards, etc.
○ Population density: this how many
of one species are in an area. If there are too many, they will have to compete
for resources and likely many will die, leaving only the fittest to survive and
reproduce.
○ Algal blooms: These occur when
there is too much nitrogen and phosphates in the water. They keep light from
filtering into the bottom of the lake, stopping photosynthesis and smothering
fish.
Essential
knowledge 2.D.2: Homeostatic mechanisms reflect both common
ancestry and
divergence due to adaptation in different environments.
1.
How do homeostatic mechanisms relate to
evolution?
- All organisms must maintain homeostasis
in order to survive and reproduce. This is so because cellular processes need
precise conditions to perform cellular processes. What is required to maintain
an organisms homeostasis and how it does it reflects common ancestry between
like organisms.
2. How is the concept of common ancestry
supported by continuity in homeostatic mechanisms?
- It is supported by organs like lungs
growing in descendants of previously water bound organisms. The Tiktalik, for
example, had both gills and lungs because it is one of the transition species
that moved from water to land.
3. How do changes in environmental
conditions affect this continuity?
- The organisms environment is the largest
impact of homeostasis; especially weather. If it’s thirty degrees out, a mammal
cant maintain homeostasis and also hunt. IT would freeze. But if it were to
evolve/mutate to grow fur, then it would be able to regulate its own temperature
without fear of freezing.
4. Explain how the following
mechanisms are used for obtaining nutrients and eliminating wastes.
○ Gas exchange in aquatic and
terrestrial plants:
- Plants take in CO2, sunlight and
water in order conduct photosynthesis. To release it they have stomata and
those open whenever the plants either needs to take in CO2 or get rid of gas
wastes (oxygen). These stomata opening and closing only when necessary prevent
too much water loss. Plants in water take in moisture and gasses through moist,
semipermeable membranes via diffusion.
○ Digestive
mechanisms in animals such as food vacuoles, gastro-vascular cavities, one-way
digestive systems
- Food vacuoles:
Vacuoles store food that has entered the cell. They can not digest them alone
so they merge with something called a lysosome, which contains the enzymes that
are able to digest this food into omething the cell can process and use as
energy.
- Gastro-vascular
cavities:
- One-way digestive
systems: This is a one-way route in which there is two openings in the
organism; a mouth and an anus. The ood goes into the mouth, is mixed with
digestive nzymes, traveles down to the stomach, intestines, etc.
○ Respiratory systems of aquatic
and terrestrial animals
- Aquatic animals: They use gills, generally
- Terrestrial animals: They use lungs, generally
○ Nitrogenous waste production and
elimination in aquatic and terrestrial animals
- It goes in the mouth and as it goes through the digestive tract, nutrients are siphoned out and the wastes exit the anus.
5. Explain how homeostatic control systems in species of
microbes, plants an animals support common ancestry. Use the following to help
illustrate your explanation:
○ The excretory systems in
flatworms, earthworms and vertebrates:
- Flatworms: food is taken in through the mouth, and while
passing through the intestine, nutrients are taken from the food. Wastes exit
through the anus.
- Earthworms: Food is taken in
through the mouth where it travels to a crop, mixing with digestive enzymes
then going to the gizzard where it is ground up. After the gizzard it enters
the intestine where nutrients are removed. The wastes are excreted from the
anus.
- Vertebrates: Food is taken into
the mouth, mixed with saliva and ground, then it goes down the esophagus to the
stomach, past the liver and into the intestine where wastes are excreted by the
anus.
○ Osmoregulation in bacteria, fish
and protists
- Bacteria:
- Fish: Fish use their gills to
take in oxygen and releases CO2. They are able to do this because of operculum,
which occurs when the gills move and water moves over the gills to exchange
dissolved gasses.
- Protists:
○ Osmoregulation in aquatic and
terrestrial plants
- Aquatic: Because the leaves and
cuticles of aquatic plants are very thin, water and gasses easily enter the
plants through diffusion when they are submerged. This allows an easy exchange
of gasses in the water without the plant having to worry about drying up.
Terrestrial: Terrestrial plants
have something called stomata, which are vents in their thick, waxy leaves. Stomata
act as a rotating door to keep water in the plant as well as open and close to
allow gas exchange.
○ Circulatory systems in fish,
amphibians and mammals
- Fish:
- Amphibians:
- Mammals:
○ Thermoregulation in aquatic and
terrestrial animals (countercurrent exchange)
- Aquatic:
- Terrestrial:
Essential
knowledge 2.D.3: Biological systems are affected by disruptions to their dynamic
homeostasis.
1. How do disruptions at the molecular and cellular levels
affect the health of the organism? Use the following to explain your answer:
○ Physiological responses to toxic
substances
- Toxins become more concentrated
as they move up the food chain(biological magnification), occasionally causing
a mass kill of tertiary and quaternary consumers. AN example is DDT, which was
washed into rivers and the fish consumed DDT laced bugs and bacteria. It
traveled up the food chain to the raptor populations and interfered with the
birds’ ability to make a strong egg shell so the eggs were busting before the
chicks could hatch.
○ Dehydration
- Symptoms of mild dehydration,
which is the loss of water in the body, are thirst and discomfort, dry skin,
dry mouth, constipation. Darker urine. Tiredness and dizziness when
standing. This is a 2% water loss.
Symptoms of moderate dehydration, which is 5-6%, includes headaches, vomiting,
no tears, sunken eyes, seizures, fainting and increased heart and respiration
rates. Severe dehydration, a 10-15%
water loss, is muscle spasms, shriveled skin, dimmed vision, reduced/painful
urination and delirium. Anything more
than a 15% loss means death.
○ Immunological responses to
pathogens, toxins and allergens
-Pathogens, toxins and allergens
cause the body to respond with inflammation, vomiting, etc to remove the toxin
from the body.
2. Provide examples of how disruptions to ecosystems can
affect the dynamics of the ecosystem. Utilize the following examples in your
responses:
●
Invasive and/or eruptive species:
- Invasive species, when introduces
to a new habitat, explode in population because they have very few or no
predators. They eat the native species who have no defense against them and
compete and sadly enough, often smother the native species into extinction.
They also destroy the environment because that ecosystem just isn’t built for
the invasive species. AN example would be the Anacondas and Pythons released in
south Florida. Those snakes have few natural predators and once they’re ten or
so feet long, no natural predators. They destroy the populations of all the
native species, even the American Alligator, the native tertiary consumer of
the everglades.
●
Human impact:
- Deforestation, poaching, pollution,
release of invasive species and more destroy animal habits and in doing so have
caused many animal species to go extinct or close to.
●
Nature’s Impact
- Hurricanes: They aren’t too
frequent but they can wash and blow away entire ecosystems. But animals that
live in hurricane prevalent areas have adapted fairly well to handle this.
- Floods: Floods wash out entire environments and
animals. They move animals around and clear areas. An area can easily recover
from even the worst flood in a couple of decades.
- Earthquakes: These often take out trees, crack the earth
and more. But they are very brief and don’t cause much worse than a rock slide,
on most occasions.
- Volcanoes volcanoes completely engulf habitats. Once the
volcanic rock begins to erode, bacteria and small plants are able to take root
and begin to rebuild the ecosystem, though it likely will not be the same as
pre-eruption.
- Fires
●
Water limitation
- When water is limited, organisms
fight for recources because al organisms need it to survive. They go into a
“survival mode” or a hibernation in order to conserve water.
●
Salination
-When salt becomes too much,
organisms may migrate to a more suitable environment.
Essential
knowledge 2.D.4: Plants and animals have a variety of chemical
defenses against
infections that affect dynamic homeostasis.
1.
Explain how plants, invertebrates and
vertebrates have multiple, nonspecific (innate) immune responses. Include how
they work and structures/chemicals involved.
- Plants:
- Invertebrates:
- Vertebrates:
2. Describe mammalian specific immune responses.
• Describe the two types of specific responses in the
Mammalian
immune system
• In the cell-mediated response,
what is the role of cytotoxic T cells?
-
They destroy infected cells
• In the humoral response, what is
the role of B cells?
-They create plasma cells which
create antibodies.
3. Explain how antigens and antibodies work together.
• What is an antibody?
- Something that is used by the
immune system to identify and neutralize pathogens.
• How does a second exposure to an
antigen differ from the primary exposure?
- There is a memory cell that keeps records of
antibodies. Antibodies are replicated and the pathogen is destroyed fairly
