Grade 8 – 4th Quarter (Living Things And Their Environment)

Herbivores are consumers that only eat plants. They do not consume meat or other animal products. They obtain their nutrients and energy solely from plant-based sources. This dietary preference distinguishes them from carnivores, which eat only meat, omnivores, which consume both plants and animals, and scavengers, which feed on dead animals or decaying matter. Herbivores have specialized digestive systems that allow them to break down and extract nutrients from plant material efficiently. They play a crucial role in ecosystems by helping to control plant populations and serving as a food source for other organisms.

Producers are organisms that have the ability to make their own food through the process of photosynthesis or chemosynthesis. They convert sunlight or inorganic compounds into organic molecules, such as glucose, which can be used as a source of energy. Examples of producers include plants, algae, and some bacteria. Consumers, detrivores, and predators, on the other hand, obtain their energy by consuming other organisms.

Excretion is the correct answer because it refers to the process of eliminating metabolic waste products from the body. This includes the removal of substances such as carbon dioxide, urea, and excess water through organs like the lungs, kidneys, and skin. Ingestion is the process of taking in food, absorption is the process of absorbing nutrients into the bloodstream, and assimilation is the process of incorporating nutrients into cells and tissues. Therefore, excretion is the only option that accurately describes the elimination of waste products.

Plants give off oxygen into the atmosphere through a process called photosynthesis. During photosynthesis, plants use sunlight, water, and carbon dioxide to produce glucose and release oxygen as a byproduct. Oxygen is essential for the survival of many organisms, including humans, as it is necessary for respiration. Therefore, the correct answer is oxygen.

During metaphase, the spindle fibers align the chromosomes along the equatorial plane of the cell nucleus. This alignment ensures that each chromosome is correctly positioned and ready for separation during the subsequent stage of mitosis, anaphase. The chromosomes are attached to the spindle fibers at their centromeres, which allows for equal distribution of genetic material to the daughter cells. Therefore, metaphase is the stage in mitosis when the chromosomes are aligned in the middle of the cell nucleus by the spindle fibers.

Consumers are organisms in an ecological food chain that receive energy by consuming other organisms. They are classified as primary, secondary, or tertiary consumers based on their position in the food chain. Primary consumers, also known as herbivores, feed directly on producers (plants) for energy. Secondary consumers are carnivores that feed on herbivores, while tertiary consumers are carnivores that feed on other carnivores. Consumers play a crucial role in transferring energy and nutrients through the food chain, ultimately sustaining the entire ecosystem.

Animals give off carbon dioxide into the atmosphere through the process of respiration. During respiration, animals take in oxygen and release carbon dioxide as a waste product. This carbon dioxide is then released into the atmosphere where it plays a role in the Earth's carbon cycle. Carbon dioxide is a greenhouse gas that contributes to global warming and climate change.

Omnivores are consumers that eat both plants and animals. They have a varied diet and can obtain nutrients from both sources. This allows them to adapt to different environments and maximize their chances of survival. Examples of omnivores include humans, bears, and pigs. They have the ability to digest and extract nutrients from a wide range of food options, making them highly versatile in their eating habits.

The highest taxonomic category is the kingdom. It is the broadest and most inclusive rank that groups together all forms of life that share certain fundamental characteristics in common. Kingdoms represent the largest classification level in the Linnaean system of taxonomy and are further divided into smaller categories such as phylum, class, order, family, genus, and species.

The correct answer is dominance. Mendel's law of dominance states that when a dominant allele is present, it completely masks the effects of a recessive allele. This means that even if an individual has one dominant allele and one recessive allele for a particular trait, the dominant allele will be expressed and the recessive allele will be hidden. This is why some traits are only seen in individuals who have two copies of the recessive allele.

Meiosis is a type of cell division that occurs in sexually reproducing organisms. It involves two rounds of division, resulting in the formation of four daughter cells. These daughter cells are haploid, meaning they have half the number of chromosomes as the parent cell. Therefore, the correct answer is 4 haploid cells.

The correct answer is prophase I - metaphase I - anaphase I - telophase I - prophase II - metaphase II - anaphase II - telophase II. This is the correct sequence of steps in meiosis. During prophase I, homologous chromosomes pair up and exchange genetic material through crossing over. Metaphase I is when the pairs of homologous chromosomes line up at the center of the cell. Anaphase I is when the homologous chromosomes separate and move to opposite ends of the cell. Telophase I is when the chromosomes reach the opposite ends of the cell and the cell starts to divide. Prophase II, metaphase II, anaphase II, and telophase II are similar to the corresponding stages in mitosis, resulting in the formation of four haploid cells.

Species is often defined as the largest group of organisms capable of interbreeding and producing fertile offspring. This taxonomic category is used to classify organisms that share similar characteristics and can reproduce with one another. The concept of a species is important in understanding the diversity and relationships between different organisms in the natural world.

Absorption is the correct answer because it refers to the process in which fluids or other substances are taken up by the tissues of the body. It occurs primarily in the small intestine, where nutrients from food are absorbed into the bloodstream and transported to the cells for energy and other functions. This process is essential for the body to obtain the necessary nutrients and maintain proper functioning. Ingestion refers to the intake of food, assimilation refers to the conversion of nutrients into usable forms, and excretion refers to the elimination of waste products.

Ingestion is the correct answer because it refers to the process of taking food into the alimentary canal. This process involves the intake of food through the mouth and into the digestive system, where it is broken down and prepared for absorption and further digestion. Ingestion is the first step in the digestive process and is essential for obtaining nutrients and energy from food.

Telophase is the stage in mitosis that occurs before cytokinesis. During telophase, the nuclear envelope reforms around the separated chromosomes, the spindle fibers disassemble, and the chromosomes begin to decondense. Cytokinesis, the division of the cytoplasm, follows telophase and completes the process of cell division. Therefore, telophase is the correct answer as it precedes cytokinesis in the sequence of events during mitosis.

Phenotype refers to the physical appearance or characteristics of a particular trait. It is the observable expression of an individual's genetic makeup (genotype). The term "phenotype" is used to describe the visible traits or characteristics that can be observed or measured, such as hair color, eye color, or height. In contrast, genotype refers to the genetic composition or combination of alleles that an individual possesses. The terms "recessive" and "dominant" are used to describe the inheritance patterns of traits, but they do not specifically refer to the physical appearance of a trait.

When the parents are pp x PP, one parent is homozygous recessive (pp) and the other parent is homozygous dominant (PP). In this case, all the offspring will be heterozygous (Pp) because they inherit one dominant allele (P) from the dominant parent and one recessive allele (p) from the recessive parent. This results in all the offspring having the purple phenotype.

Mendel's law of independent assortment states that alleles on different chromosomes are distributed randomly to individual gametes. This means that the inheritance of one trait is not dependent on the inheritance of another trait. This law explains how different traits can be inherited independently of each other, leading to genetic variation in offspring.

Assimilation refers to the process by which components or chemicals from food are taken into the cells of the body after the food or beverage has been digested and absorbed. This process involves the absorption of nutrients and their conversion into forms that can be used by the body for energy, growth, and repair. It is an essential step in the digestive process as it ensures that the body receives the necessary nutrients from the food consumed.