Information for Final Exam | Môn Biology - Trường Đại học Quốc tế, Đại học Quốc gia Thành phố Hồ Chí Minh

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Dear my students, yesimola.kepat
Please review these 20 questions for Final Exam. 1)
Describe evidence for evolution by natural selection.
Natural selection is one of the key themes in evolutionary theory. When parents have a
diversity of offspring, nature determines which of those variants get to live and
propagate, merely by being challenging to exist in. Over multiple generations, creatures
become fitter and fitter for survival and reproduction within their specific environments.
The hypothesis of evolution is supported by a variety of sorts of evidence: - Physical Evidence:
+ Fossil evidence, such as that seen in hominids and horses, demonstrates the evolution
of lineages across millions of years.
+ Comparative anatomy research helps scientists to detect homologous features, such
as leg bones, among broad groupings of related creatures. For instance, the bones within
the appendages of a person's, dog, bird, and whale all share identical overall construction. - Biological Evidence:
+ Molecular Biology: The fact that DNA is universal and the genetic code for proteins
is almost universal indicates that all life originally shared a common ancestor. DNA
also hints at how evolution may have occurred.
+ Biogeography: provides further information regarding evolutionary links. The
occurrence of similar creatures across confirming a hybrid zygote that may have
evolved. Some flora and fauna of the northern continents, for example, are comparable
across these landmasses but unique from those of the southern continents. Islands such
as Australia and the Galapagos chain frequently feature distinct species that originated
after these landmasses split from the mainland. 2)
Explain how sexual recombination generates genetic variability.
Sexual recombination occurs when half of one parent's genes mix with half of the other
parent's genes in the offspring, resulting in a unique gene combination. The amount of
variety in a population would rise through sexual recombinations and mutations. Sexual
recombination continuously produces new variants in the population. In sexually
reproducing organisms, recombination of alleles is more significant than mutation in
establishing the genetic variations that allow adaptation. Without this, the mutation is
the only way to evolve diversity. 3)
Describe and provide examples of prezygotic and postzygotic reproductive barriers.
a/ Prezygotic reproductive barriers are the barrier that prevents mating or fertilization
from occurring. It includes 5 types of isolation:
- Temporal isolation occurs when 2 species reproduce at different times of the year. lOMoAR cPSD| 59078336
+ Example: two toad species have an overlapping geographic range but different mate seasons.
- Habitat isolation (ecological isolation): occurs when 2 species inhabit similar regions,
but rarely encounter each other because of different habits.
+ Example: Northern red-legged frogs (Rana aurora) breed in fast-moving, ephemeral
streams, whereas American bullfrogs (Rana catesbeiana) breed in permanent ponds, so they are isolated.
- Gametic isolation: Sperm from one species may be unable to fertilize eggs from
another because incompatible physically or chemically.
+ Example: In plants, pollen grains from one species often do not germinate on the
stigma of another species, resulting in pollen tubes never reaching the ovary, where
fertilization would take place.
- Mechanical isolation: takes place when genital differences preclude copulation, or
separate animals pollinate flowers.
+ Example: two bushbabies belonging to different species can not mate together.
- Behavioral isolation: happens when two species respond to distinct courting rituals.
+ Example: Male fireflies notify their female counterparts by flashing light pulses in
certain patterns; the females recognize them as one of their own and respond.
b/ Postzygotic reproductive barriers are the barrier that exists after forming a hybrid
zygote that prevents the hybrid zygote from growing into a viable, fertile adult. There
are 3 types of postzygotic reproductive barriers:
- Hybrid inviability: the offspring (called a hybrid) dies before birth or can not surviveuntil adulthood.
+ Example: hybrid zygotes of sheep and goats die before birth.
- Hybrid sterility: the hybrid is infertile.
+ Example: mules are the sterile offspring of a female horse and a male donkey.
- Hybrid breakdown: the first generations are fertile but their offspring are infertile.
+ Example: the first-generation hybrids of lions and tigers are healthy, but the future
generations become weak or sterile. 4)
List and explain the functions of the extraembryonic membranes.
4 extraembryonic membranes form around the embryo: the chorion (the combination
of trophoblast plus underlying extraembryonic mesoderm), amnion, yolk sac, and allantois.
The yolk sac is an endoderm-lined membrane surrounding the blastocoel, which is now
known as the yolk sac cavity. The yolk sac is no longer useful in humans, but it exists
as a relic of our ancestors, who relied on stored yolk for embryonic sustenance. Most
mammalian eggs lack a yolk, and nutrients are transported from maternal to embryonic lOMoAR cPSD| 59078336
circulation via the placenta. Early in development, the human yolk sac degenerates.
However, before it does so, it provides the embryo with blood cells. -
The allantois: is a tiny, endodermal-lined diverticulum located off the hindgut's
ventral side. Although it has crucial tasks in waste storage and gas exchange in birds
and reptiles, the human allantois is a vestigial sac that serves no such use. These tasks
are carried out by the placenta and the umbilical vessels that develop beside the allantois. -
The amnion: is a thin ectodermal membrane lined with mesoderm that expands
to envelope the embryo-like a balloon, which surrounds the embryo. It is filled with a
transparent fluid produced by a variety of sources, including the fetal skin, the amnion,
the fetal kidneys, and perhaps the fetal arteries. -
The chorion: is formed from the cytotrophoblast and surrounds the embryo after
about one month of development; the chorion finally unites with the amnion. The
chorion has two purposes: it creates chorionic fluid to protect the embryo and it also
serves as a source of nutrition for the embryo. The chorionic fluid is found in the
chorionic cavity, which is the region between the chorion and the amnion. The
chorionic fluid protects the embryo by absorbing stress caused by stimuli such as
movement. To nurture the embryo, the chorion develops chorionic villi, which are
chorion extensions that enter through the uterine decidua (endometrium) and eventually
join with the mother's blood arteries. 5)
Describe three traits that characterize modern vascular plants and explain
how these traits have contributed to success on land.
- Life cycles dominated by sporophytes
- Vascular tissues known as xylem and phloem
- Well-developed roots and leaves 1.
Dominant sporophytes: As a result, the gametophyte became nearly invisible to the naked eye. 2.
Transport through xylem and phloem: These allowed plants to transport
minerals, water, and other organic compounds, allowing them to grow taller and thicker. 3.
Leaves and roots- Increasing the surface area of leaves allows plants to collect
more solar energy for photosynthesis.
Roots are organs that help vascular plants grow taller by anchoring them to the soil and
allowing them to absorb water and nutrients from the soil. 6)
Describe the role of the extracellular matrix in embryonic development. 7)
Describe the evidence that steroid hormones have intracellular receptors,
while water-soluble hormones have cell-surface receptors. lOMoAR cPSD| 59078336 -
Steroid hormones are lipid-soluble, easily pass through cell membranes, move
in thecirculation linked to transport proteins, and diffuse through the plasma membrane
of target cells. Cells sensitive to steroid hormones contain intrinsic receptor molecules
that bind specifically to that hormone. Transcriptional factors are frequently found in
intracellular receptor proteins. -
Frogs have melanosomes, which means the skin is lighter when they are
concentrated around the nucleus and darker when they are distributed throughout the
cytoplasm. The melanosomes distributed throughout the cytoplasm when the
melanocyte-stimulating hormone was injected into the interstitial fluid surrounding the
cell. There was no dispersion when they were directly injected into the cell. 8)
Explain how the antagonistic hormones insulin and glucagon regulate
carbohydrate metabolism.
In healthy persons, the insulin glucagon feedback loop should be balanced out accordingly.
When you ingest carbohydrates, you tell the pancreas to release insulin.
Insulin increases glucose absorption and glycogen production in muscle and liver cells.
After a period, glucose levels begin to fall, and the pancreas secretes glucagon.
Glucagon increases glycogen breakdown, increases glucose production, and inhibits glycogen storage.
Glucagon compensates for low blood sugar levels by increasing the amount of glucose in the blood.
Insulin reduces high blood sugar levels by guiding glucose into cells.
In cases of insulin resistance, diabetes, obesity, or simply poor hormonal status, you
may be able to offset this feedback loop in some way by having chronically high levels
of insulin or glucagon or not being able to produce enough insulin in response to a meal
that raises your blood sugar, causing more hyperglycemia. 9)
Relate structure with function and identify diagrams of the following
animal tissues: epithelial, connective tissue (six types), muscle tissue (three types), and nervous tissue. - Epithelial tissues:
+ Epithelial tissues are made up of cells that cover surfaces such as the skin's surface
and line tubes and cavities such as the digestive organs, blood vessels, kidney tubules,
and airways. Because the cells of an epithelial layer are joined by semi-permeable
junctions, this tissue acts as a barrier between the external environment and the organ
it covers. In addition to this protective role, epithelial tissue may be adapted to act in
secretion and absorption. Epithelial tissue protects organisms against pathogens,
damage, and fluid loss. All epithelial tissues are free surfaces connected to the
underlying layers via a basement membrane. lOMoAR cPSD| 59078336
+ Epithelial cells can be cuboidal (shaped like dice), columnar (shaped like bricks on
end), or squamous in shape (like floor tiles)
+ The arrangement of epithelial cells can be basic (single-cell layer), stratified (many
tiers of cells), or pseudostratified (many tiers of cells) (a single layer of cells of varying length) - Connective tissue:
+ Connective tissues are made up of individual cells that float in a matrix. Connective
tissues are fibrous tissues. They are made up of cells that are divided by a non-living
material known as a matrix. Organs are shaped and held in place by connective tissues.
Connective tissue includes both bone and blood. Connective tissue, as the name
implies, offers a "connecting" role. It both supports and binds other tissues. It is made
up of sparsely packed cells that are distributed throughout an extracellular matrix. The
matrix is made up of fibers that are suspended in a liquid, jelly-like, or solid base.
• In vertebrates, the fibers and foundation unite to form six major forms of connective tissue:
+ Loose connective tissue connects epithelia to underlying tissues and holds organs in place.
+ Cartilage is strong and flexible support material.
+ Fibrous connective tissue is present in tendons, which connect muscles to bones, and
ligaments, which connect bones at joints.
+ Adipose tissue stores fat for insulation and fuel.
+ Blood consists of blood cells and cell fragments in the form of blood plasma.
+ Bone is mineralized and creates the skeleton. - Muscle tissue:
+ Muscle is composed of lengthy cells known as muscle fibers that contract in response
to nerve signals. Muscle tissue generates force and causes movement within interior
organs. In the vertebrate body, muscle tissue is separated into three distinct categories:
+ Smooth muscle, which is located in the inner linings of organs, appears unstriated
(not striped). Smooth muscle contraction can be rather slow, and it frequently occurs
naturally and without our conscious control. Some refer to it as involuntary muscle. It
is rarely exhausted. Smooth muscle is present in the gastrointestinal tract, where it
squeezes food along the intestines via peristalsis. It is present in the walls of our blood
vessels, where it can widen or narrow the vessel, enabling more or less blood to flow.
+ When seen under a microscope, skeletal muscle and voluntary muscle appear striped
or striated. This is due to banding in the muscle caused by the pattern of actin and
myosin protein filaments. Skeletal muscle is connected to the skeleton's bones. Skeletal
muscle quickly fatigues or tires. It also contracts swiftly and is regulated by our
conscious mind. The biceps are formed of skeletal muscle, and when it contracts, it
shortens, causing the lower arm to rise. Skeletal muscles are frequently grouped in lOMoAR cPSD| 59078336
antagonistic pairs, which means that if one muscle moves a limb in one direction, the
other muscle moves it the opposite way.
+ Cardiac muscle is striated like skeletal muscle, but it has cross bridges or
crossconnections that connect muscle fibers. Cardiac muscle is myogenic, which means
it generates its impulse to contract and circulate blood throughout an organism. It is
exclusively found in the heart and contracts rhythmically at a speed determined by the
brain without ever becoming fatigued. - Nervous tissue:
+ Neural tissue is made up of the cells that make up the central nervous system and the
peripheral nervous system. The brain and spinal cord are formed by neural tissue in the
central nervous system, and the cranial nerves and spinal nerves, including sensory and
motor neurons, are formed by neural tissue in the peripheral nervous system. Nerve
tissue's role is to convey electrical messages throughout the body. Nervous tissue contains:
- Neurons or nerve cells transmit nerve impulses.
- Glial cells, also known as glia, are cells that assist nourish, insulate, and replenish neurons. 10)
Explain how the hypothalamus and the pituitary glands interact and how
they coordinate the endocrine system in the male.
The interaction of the hypothalamus and pituitary glands (known as the
hypothalamicpituitary axis) is a feedback control system. The hypothalamus gets input
from practically every other component of the central nervous system and uses it to
send signals to the pituitary gland. In response, the pituitary gland secretes a variety of
hormones that stimulate various endocrine glands throughout the body. The
hypothalamus detects changes in the circulating amounts of hormones generated by
these endocrine glands and adjusts its stimulation of the pituitary gland to maintain homeostasis.
The hypothalamus affects the anterior and posterior pituitary lobes' functions in distinct
ways. Neurohormones created in the hypothalamus travel to the anterior pituitary
(adenohypophysis) via a specialized portal vascular system, where they govern the
production and release of the anterior pituitary's six primary peptide hormones. These
anterior pituitary hormones control peripheral endocrine glands (such as the thyroid,
adrenals, and gonads) and growth and breastfeeding. There is no direct neuronal
connection between the hypothalamus and the anterior pituitary gland.
The posterior pituitary (neurohypophysis) is made up of axons that originate from
neuronal cell bodies in the hypothalamus. These axons serve as storage sites for two
peptide hormones generated in the brain, vasopressin (antidiuretic hormone) and
oxytocin; these hormones work in the periphery to regulate water balance, milk
ejection, and uterine contraction.
Almost all hormones generated by the brain and pituitary gland are released in a
pulsatile fashion, with periods of activity interspersed with periods of inactivity. Some
hormones have distinct circadian rhythms (for example, adrenocorticotropic hormone lOMoAR cPSD| 59078336
[ACTH], growth hormone, and prolactin); others (for example, luteinizing hormone
and follicle-stimulating hormone during the menstrual cycle) have month-long rhythms
with superimposed circadian rhythms. 11)
Explain how the uterine and ovarian cycles are synchronized and describe
the functions of the hormones involved.
The ovarian cycle refers to the process through which an egg matures, erupts from the
ovary, and travels down the oviduct to the uterus. The cycle lasts on average 28 days
and varies in duration. The ovarian cycle is closely linked to the uterine cycle, during
which the uterine lining develops and prepares for an embryo to implant. If the egg has
not been fertilized and an embryo has not implanted before the end of the cycle, the
uterine lining sloughs off in a process known as menstruation.
Ovarian and Uterine Cycle Events
1. Each woman’s ovaries contain around 200,000 immature eggs, known as primary
oocytes when she reaches sexual maturity. A primary oocyte is a diploid (2n) cell
that is in prophase I of meiosis. Each main oocyte is surrounded by a layer of
follicular cells. A follicle is made up of an oocyte and its follicle cells.
2. An ovarian cycle lasts around 28 days, commencing with the first day of
menstruation, also known as menses. Six to twelve primary oocytes develop over
the first seven days of the cycle. As the follicles grow, the follicle cells connect with
the oocytes and provide nutrients to them via pores known as gap junctions.
3. Each egg increases in size, while the surrounding follicle cells split and multiply,
producing thousands of follicle cells in a single follicle.
4. All but one of the developing follicles begin to deteriorate by day 7. The surviving
follicle develops further, and its follicle cells continue to nourish it as well as supply
it with proteins and informational molecules required for the early stages of development.
5. The developing main oocyte completes meiosis I and splits into two haploid (n)
cells. Half of the chromosomes are distributed to each of these cells. One cell,
known as a polar body, however, receives very little cytoplasm. The second oocyte,
now a secondary oocyte, starts meiosis II and remains there until fertilization.
6. Ovulation happens on day 14, and the secondary oocyte emerges from the ovary.
Microscopic cilia in the oviduct beat and pull in the liberated oocytes. This
immature egg enters an oviduct and may be fertilized by a sperm cell, completing meiosis.
7. The follicular cells that remain grow into the corpus luteum, a tiny mass of
endocrine tissue. For two weeks, the corpus luteum stays in the ovary, secreting
the hormones estrogen and progesterone. If a woman is not pregnant after her
ovarian cycle, the corpus luteum disintegrates.
8. The ovarian cycle and the uterine cycle are inextricably linked each month. The
uterine lining swells up and then smashes off throughout the uterine cycle. The
cycle begins with the uterine lining sloughing. This is the first day of menstruation,
commonly known as menstruation. lOMoAR cPSD| 59078336
9. After menstruation, the uterine lining begins to regenerate and prepare for embryo
implantation. The uterine lining proliferates throughout this period of the uterine
cycle, up to ovulation. This tissue receives nutrition from capillary beds.
10. The capillary beds deteriorate just before menstruation and no longer supply
nutrients to the surrounding tissue. This tissue dies and sloughs off via the vagina
to the exterior of the body during menstruation.
The ovarian cycle is governed by the interaction between the pituitary gland and ovarian
hormones. The anterior pituitary gland begins to enhance the release of two hormones
a few days before the start of the cycle: follicle-stimulating hormone (FSH) and
luteinizing hormone (LH) (LH).
FSH and LH stimulate the growth of ovarian follicles. The follicles begin to release
estrogen as they develop. Increasing levels of estrogen feedback on the pituitary limit
the production of further FSH and LH during this period of the cycle. FSH and LH
levels fall during the next week.
Beginning about day 12, rising estrogen levels have an unexpectedly negative effect on
the pituitary gland. Instead of providing negative feedback to the pituitary, these
hormones now provide positive feedback, encouraging the pituitary to produce
excessive quantities of FSH and LH.
On day 14 of the ovarian cycle, LH reaches a peak. This LH surge causes the mature
follicle to break and release the egg, initiating the ovulation process. The remaining
follicle cells are subsequently stimulated by LH to develop into the corpus luteum,
which secretes estrogen and progesterone.
For the remaining two weeks of the cycle, the corpus luteum stays in the ovary,
secreting estrogen and progesterone. These hormones again limit the production of FSH
and LH at this stage in the cycle. A decrease in FSH and LH prevents follicles from
developing during the second part of the cycle.
LH (or a hormone generated by an implanted embryo) is necessary to keep the corpus
luteum alive. If no embryo has implanted by the conclusion of the cycle, the corpus
luteum degenerates. The corpus luteum no longer produces estrogen and progesterone as it degenerates.
The ovarian and uterine cycles are inextricably linked. Hormones produced by the
ovary at various stages of the ovarian cycle cause uterine lining alterations. For
example, at the start of the cycle, estrogen and progesterone levels are too low to
maintain the uterine lining, and menstruation begins.
The growing follicle increases its release of estrogen around a week into the ovarian
cycle, and estrogen levels in the body begin to rise. This hormone causes the uterine
lining cells to multiply, causing the lining to thicken.
The level of estrogen in the body has peaked just before ovulation. Following that, the
remaining follicle cells in the ovary mature into the corpus luteum, a tissue that
produces estrogen and progesterone. The hormones keep the uterine lining at its
thickest and most prepared for embryo implantation. lOMoAR cPSD| 59078336
If the egg is not fertilized or has not been implanted before the end of the cycle, the
corpus luteum breaks down and ceases producing estrogen and progesterone. The
uterine lining also breaks away in the absence of these hormones, resulting in menstruation. 12)
What is spermatogenesis? Describe the process of spermatogenesis.
Spermatogenesis is the process by which sperms are produced from immature male
germ cells. It begins during puberty and typically lasts until death, but there is a modest
reduction in sperm quantity with increasing age. The process:
Stage1: The initial diploid spermatogonium in the seminiferous tubules contains twice
as many chromosomes, which replicate mitotically in interphase before meiosis 1 to
create 46 pairs of sister chromatids.
Stage2: The chromatids exchange genetic information via synapsis before splitting into
haploid spermatocytes via meiosis.
Stage3: During the second meiosis division, the two new daughter cells split further
into four spermatids, each with half the amount of chromosomes as the original spermatogonium.
Stage 4: These cells now migrate through the lumen of the testes to the epididymis,
where they evolve into four sperm cells by developing microtubules on the centrioles,
creating an axoneme, i.e., a basal body, and some of the centrioles lengthen to create
the sperm tail, aided by testosterone. 13)
What is oogenesis? Describe the process of oogenesis.
The production of female gametes is known as oogenesis. This procedure starts inside
the fetus before birth. Before birth, the stages in oogenesis that lead to the creation of
primary oocytes occur. Primary oocytes do not split further. They either develop into
secondary oocytes or degenerate.
Oogenesis takes place in the ovaries' outermost layers. Oogenesis begins with a germ
cell called an oogonium, which then undergoes mitosis to multiply. The oogenesis
process is divided into three stages:
- Pre-natal Stage: The main oocyte develops when halted in meiosis-I. Follicular cells
proliferate and differentiate into a stratified cuboidal epithelium. Granulosa cells are
the name given to such cells. These cells produce glycoproteins, which help to create
the zona pellucida that surrounds the main oocyte.
- Antral Stage: The fluid-filled region between granulosa cells joins to create the
antrum, which is a central fluid-filled cavity. These are termed secondary follicles.
These secondary follicles grow during the monthly cycle under the influence of
follicle-stimulating hormone and luteinizing hormone.
- Phe-ovulation Stage: This stage is triggered by an LH surge, and it is where meiosis-
I concludes. Within the follicle, two haploid cells of different sizes develop. A polar
body is formed by one of the daughter cells that receive less cytoplasm. This cell
does not take part in the development of the ovum. The secondary oocyte is the name lOMoAR cPSD| 59078336
given to the other daughter cell. Meiosis-II occurs in the two daughter cells. The
polar body multiplies to create two polar bodies, whereas the secondary oocyte
arrests in meiosis-II metaphase. 14)
Describe transportation in vascular tissue: Water-Conducting Cells of the
Xylem and Sugar-Conducting Cells of the Phloem.
- Water transfer in vascular tissue – conducting cells of the xylem:
+ Water transport is a passive mechanism.
+ The ability to transfer material from one place to another is based on two fundamental
phenomena: osmosis and attraction.
+ The following forces move water and mineral ions: root pressure generates a force
that pushes water up from the bottom, attraction force due to transpiration in leaves,
and binding force between water molecules and the wood vessel wall. It then establishes
a constant flow of transport from the roots to the leaves.
The transfer of water in vascular tissue - conducting cells of the phloem:
+ Translocation is the process of moving food via the phloem.
+ They are in charge of delivering sugars and other compounds generated by photosynthesis.
+ It happens by active transport, which uses ATP energy and follows the concentration gradient of the sugar. 15)
What is the difference between gymnosperms and angiosperms? What
advantage did angiosperms have over gymnosperms? Angiosperms Gymnosperms Definition Flowering plants Non-flowering plants
produce seeds that are produce seeds that are
contained within an unenclosed or "naked." ovary. Seeds Enclosed within an Unenclosed and found
ovary, typically in a fruit. on scales, leaves, or as cones. Flowers Produce flowers and Do not produce flowers fruits and fruits lOMoAR cPSD| 59078336 Life cycle Seasonal (die in Evergreen autumn/fall) Double fertilization Show double Do not show double fertilization fertilization Reproductive system Cones; unisexual Present in flowers; can be unisexual or bisexual Reproduction Mostly rely on Mostly rely on wind. pollinators. Leaves Flat Needle-like, scale-like Wood Hardwood Softwood Perenniality Non-perennial Perennial Uses Medications, food, Paper, lumber, etc clothing, etc
Angiosperms contain seeds that are encased in fruits, whereas gymnosperms
have bare seeds. Furthermore, angiosperms produce flowers, but
gymnosperms do not. Another distinguishing trait of angiosperms is twofold
fertilization, which gymnosperms lack. Rather than relying on wind pollination,
angiosperms attract bees and other insects (through the colors and decorations
of their blooms), which gather and disperse pollen (insect pollination). Wind
pollination is less reliable than insect pollination. 16)
Describe the difference between vascular and nonvascular plant.
Vascular plants are higher plants of the Tracheophyta plant family. They are
made up of a highly specialized vascular system or tissue. This vascular system
also includes two primary complicated tissues, phloem, and xylem. These
phloem and xylem are in charge of transporting nutrients and water throughout
the body, respectively. In addition, the vascular tissues sustain and rigidify the
plant. Plants' strength is provided by lignified tissues linked with the xylem.
Nonvascular plants are those that lack vascular systems. They are lowgrowing
plants. These plants lack xylem and phloem tissues. They do, however, have
specific tissues for water transfer. Nonvascular plants include bryophytes such
as liverworts, mosses, and hornworts. Because vascular tissues are lacking in
this category, they lack a proper stem, root system, and leaves. Furthermore,
non-vascular plants lack a diverse range of specialized tissues. As a result,
several of the plants in this group resemble leaves (liverworts). Rhizoids are lOMoAR cPSD| 59078336
root-like structures found in certain plants. Nonvascular plants have a high rate
of gametophyte development. Those are haploid gametophytes. Vascular plants Nonvascular plants Definition
the group of plants that the group of plants that
have a vascular system do not have vascular
that transports food and systems water throughout the plant Diversity Higher Low Vascular system Present Absent
True stem, leaves, and Have true stem, leaves, Instead of real roots and roots structures, have stems, leaf-like structures, and rhizoids. Plant strength Lignified tissues are These plants are
found in xylem tissues sensitive and shorter
and offer support and than vascular plants stiffness to the plant. because of a lack of water-conducting tissues. Prominent generation Sporophytes Gametophytes Plant examples
Ferns, conifers, and Bryophytes, including flowering plants. liverworts. mosses, and hornworts. Drought resistance
All most all the vascular Non-vascular plants are plants are
drought vulnerable. As a result, resistant. they are linked with water sources or wetlands. 17)
Describe the four nutrient reservoirs and the processes that
transfer the elements between reservoirs.
- Water: Reservoirs, oceans, and so on.
Evaporation, precipitation, transpiration, condensation, and movement via
surface and groundwater are all forms of transfer. lOMoAR cPSD| 59078336
- Carbon reservoirs include fossil fuels, soils and sediments, ocean
solutes, plant and animal biomass, and the atmosphere.
Photosynthesis, volcanoes, and fossil fuel combustion are all examples of transfer.
- Nitrogen: Reservoirs: Atmosphere Transfer: nitrogen fixation by bacteria,
- Phosphorus reservoirs include sedimentary rocks of marine origin, the ocean, and life.
Transfer: Phosphate binds to soil particles, thus movement is frequently confined. 18)
Describe how human activities increase CO2 in the atmosphere, the
logic behind how that leads to global warming, and what humans
have done about global warming?
Human actions on Earth are altering the natural greenhouse effect. The use of
fossil fuels such as coal and oil has raised the concentration of carbon dioxide
in the atmosphere during the last century (CO2). This occurs as a result of the
coal or oil burning process, which mixes carbon with oxygen in the air to
produce CO2. To a lesser extent, land clearance for agriculture, industry, and
other human activities has boosted greenhouse gas concentrations.
The effects of altering the natural atmospheric greenhouse are difficult to
predict, although several are likely:
On average, the Earth will warm. Warmer temperatures may be welcomed in
certain areas, but not in others.
Warmer temperatures will almost certainly result in increased evaporation and
precipitation overall, but particular locations may differ, with some being wetter and others dryer.
Increased greenhouse gas emissions will warm the ocean and partially melt
glaciers and ice sheets, rising sea levels. Warming ocean water will also
expand, adding to increased sea-level rise.
Higher amounts of atmospheric carbon dioxide (CO2) can have both good and
negative impacts on crop yields outside of a greenhouse. Some laboratory tests
indicate that increased CO2 levels can boost plant growth. Other variables,
such as shifting temperatures, ozone, and water and nutrient limitations, may
more than offset any possible gain in production. If optimum temperature
ranges for particular crops are surpassed, prior potential production
improvements may be diminished or reversed entirely.
Climate extremes, such as droughts, floods, and excessive temperatures, can
cause crop losses and jeopardize agricultural producers' livelihoods as well as
global food security. Weeds, bugs, and fungus can thrive in warmer lOMoAR cPSD| 59078336
temperatures, wetter climates, and higher CO2 levels, depending on the crop
and environment, and climate change will certainly increase weeds and pests.
Finally, while increased CO2 levels can promote plant growth, research has
revealed that they can also impair the nutritional value of most food crops by
lowering protein and key mineral concentrations in most plant species. Climate
change can result in the emergence of new pest and disease patterns,
impacting plants, animals, and humans and creating new threats to food
security, food safety, and human health. 19)
Describe the value of biodiversity in maintaining the global ecosystem.
Biodiversity, often known as biological diversity, refers to the variety of living
things on Earth. In a brief, it is defined as a degree of variety in life. The
biological diversity includes microorganisms, plants, animals, and ecosystems
such as coral reefs, woods, rainforests, and deserts.
Biodiversity also refers to the quantity or abundance of various species found
in a given area. It reflects the abundance of biological resources at our disposal.
It all comes down to preserving the natural space, which is made up of a
community of plants, animals, and other living things, which is being steadily
decreased as we plan human activities that are being reduced by habitat loss.
Maintaining Ecosystem Balance: Recycling and storing nutrients, combating
pollution by breaking it down and absorbing it, stabilizing climate, protecting
water resources, circulation and cleansing of air and water, global life support
(plants absorb CO2, give out 02), forming and protecting soil, recovering from
unexpected events, and maintaining stream and river flows throughout the world. 20)
What is overexploitation and how is it affecting life on Earth today?
Overexploitation, also known as overharvesting, is when a renewable resource
is harvested to the point of decreasing returns. Continued overexploitation may
result in the resource's demise. Natural resources include things like wild
medicinal herbs, grazing pastures, game animals, fish stocks, forests, and water aquifers.
The phrase is used by ecologists to characterize populations that are harvested
at an unsustainable rate. This can lead to population extinction and possibly
the extinction of whole species. The word is often used in conservation biology
to refer to human economic activity that entails the exploitation of biological
resources in greater quantities than their populations can tolerate. In fisheries,
hydrology, and natural resource management, the word is used and defined in
slightly various ways. Overexploitation of resources can result in resource
depletion, even extinction. Overfishing can be employed in the context of lOMoAR cPSD| 59078336
fishing, stock management, overgrazing, forest management, aquifer
management, and endangered species monitoring.
As an example, trawls have wiped off long-lived mollusk and echinoderm
species in the North Sea. Trawling for demersal species hurts the habitat of
species other than the target species. The seafloor is trawled over at least twice
a year, and the gear (beam trawling) is becoming heavier with time. As a result,
the Dutch beam trawl fishery has shifted to pulse fishing, which necessitates
lighter beam trawls. However, whether this approach creates less
environmental impact is debatable. As a consequence, the European
Commission has declared this fishing practice illegal.