BT201 Final Term Subjective 2024 by Sulman Ali

SUBJCTIVES OF CURRENT PAPER · BT201 - Ecology, Biodiversity & Evolution-II · Final-Term File 2024 By · SULMAN ALI (BS-ZOOLOGY)

Importance of Bacteria? OR Role of Bacteria in Environment?

The ecosystem, both on land and in the water, depends heavily upon the activity of bacteria. The cycling of nutrients such as carbon, nitrogen, and sulfur is completed by their ceaseless labor. Decomposition is the breakdown of these organisms, and the release of nutrients back into the environment, and is one of the most important roles of the bacteria.

Food Web? / Food Web and Structure of Communities

Definition of Food Web: A food web summarizes the feeding relations in a community. It illustrates the complex interactions between different species, where each species is connected to others through predator-prey relationships.

Structure of Community: The structure of a community can be influenced by the feeding activities of keystone species, which control community dynamics. For instance, in a simple food web, plants are eaten by grasshoppers and squirrels. Predators like foxes and eagles consume these herbivores, and decomposers like earthworms and bacteria break down dead organisms. Keystone species, such as certain predators, can enhance species diversity by preventing competitive exclusion.

Correct sequencing of Organism DNA protein RNA function’s arrange them in order:

In organisms, DNA, RNA, and proteins play crucial roles in various functions. Here is the order in which they function:

1. DNA (Deoxyribonucleic Acid): DNA is the genetic material that carries the instructions for the development, functioning, and reproduction of all living organisms. It serves as a blueprint for the synthesis of RNA and proteins.
2. RNA (Ribonucleic Acid): RNA is a molecule that is transcribed from DNA and plays a vital role in protein synthesis. There are different types of RNA, including messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
3. Protein: Proteins are large, complex molecules made up of amino acids. They perform a wide range of functions in cells, including catalyzing chemical reactions, providing structural support, transporting molecules, and serving as signaling molecules

In summary, DNA provides the instructions, RNA helps in the synthesis of proteins based on those instructions, and proteins carry out various functions essential for the organism's survival and functioning.

Less correlation between mRNA and protein abundance:

The lack of correlation between mRNA and protein abundances is a phenomenon observed in cells. Control mechanisms at the ribosomes, where mRNA is translated to peptides, contribute to this disparity. Translational control mechanisms enable cells to selectively translate certain mRNAs while blocking others, influencing protein production. This lack of direct correlation suggests that post-transcriptional processes, such as translational control, play a crucial role in regulating protein abundance independently of mRNA levels.

What is industrial ecology:

The design of the industrial infrastructure such that it consists of a series of interlocking "technological ecosystems" interfacing with global natural ecosystems. Industrial ecology takes the pattern and processes of natural ecosystems as a design for sustainability. It represents a shift in paradigm from conquering nature to becoming nature.

What happen when organisms have limited access to resources ?/ Optimal foraging theory

Optimal foraging theory attempts to model how organisms feed as an optimizing process.

Evolutionary ecologists predict that if organisms have limited access to energy, natural selection is likely to favor individuals that are more effective at acquiring energy and nutrients. Many animals select food in a way that appears to maximize the rate at which they capture energy. Plants appear to allocate energy to roots versus shoots in a way that increases their rate of intake of the resources that limit their growth. Plants in environments with abundant nutrients but little light tend to invest more energy in the growth of stems and leaves and less in roots. In environments rich in light but poor in nutrients, plants tend to invest more energy in the growth of roots.

Endosymbiotic theory and origin of eukaryotic evolution?

Endosymbiotic Theory: The endosymbiotic theory suggests that eukaryotic cells originated from the symbiotic relationship between several prokaryotic cells. This prolonged association led to the integration of these cells, forming organelles like mitochondria and plastids, which possess their own genetic material and protein-synthesizing capabilities.

Origin of Eukaryotic Evolution: Eukaryotic evolution involved the incorporation of free-living bacteria into a host cell, establishing a symbiotic relationship. Over time, these bacteria became integral parts of the eukaryotic cell, contributing to its complexity and ability to synthesize proteins through distinct systems.

Which is earliest organisms which introduce oxygen in environment?

The earliest organisms to introduce oxygen into the environment were cyanobacteria. These photosynthetic bacteria, also known as blue-green algae, began producing oxygen through photosynthesis around 2.4 to 2.5 billion years ago during the Great Oxygenation Event (GOE). This event significantly increased the levels of oxygen in Earth's atmosphere, paving the way for the evolution of more complex aerobic life forms.

Keystone specie in detail;

A keystone species is a species that has a disproportionately large effect on community structure relative to its biomass or abundance. Keystone species differ from foundation species in two main ways: they are more likely to belong to higher trophic levels (to be top predators), and they act in more diverse ways than foundation species, which tend to modify their environment. Different sources use different definitions for keystone and foundation species. If your class requires you to know these definitions, make sure to consult your book or teacher for the definition you should use. In some sources, foundation species are viewed as a subcategory of keystone species.

Organelles capable of protein synthesis?

Eukaryotic cells contain organelles capable of protein synthesis. These organelles, such as mitochondria and plastids, possess their own genetic material and protein-synthesizing capabilities. This supports the endosymbiotic theory, which suggests that these organelles were once free-living bacteria that entered into a symbiotic relationship with a host cell. This integration eventually led to the development of complex eukaryotic cells, which have a combination of protein-synthesizing systems derived from both the host and the symbiotic bacteria.

What are transposons?

Transposable elements (insertion sequences and transposons) can transfer copies of themselves to other DNA molecules (chromosome, plasmid, or viral DNA). Antibiotic resistance genes rapidly spread within and between bacterial populations by transposons carried on F factors called R plasmids.

Factor Affecting Decomposition of Environment?

Decomposition rate is influenced by temperature, moisture, and chemical composition of litter and the environment. The rate of decomposition affects the rate at which nutrients, such as nitrogen and phosphorus, are made available to primary producers. Rates of decomposition in terrestrial ecosystems are higher under warm, moist conditions. The rate of decomposition in terrestrial ecosystems increases with nitrogen content and decreases with the lignin content of litter. The chemical composition of litter and the availability of nutrients in the surrounding environment also influence rates of decomposition in aquatic ecosystems.

Differentiation between Shared Ancestral and Shared Derived Characters

A shared ancestral character originated in an ancestor of a taxon and is present in both the ancestor and its descendants. In contrast, a shared derived character is an evolutionary novelty unique to a particular clade, appearing first in the most recent common ancestor of that clade. Systematics use outgroup comparisons to differentiate between these characteristics, determining which traits are ancestral and which are derived by examining how these traits appear in both the in group and closely related outgroup species.

Advantage/Disadvantages to Being Multicelled / single celled

For something on the order of 1.5 billion years all organisms were single-celled and life seems to have thrived. In fact, single-celled organisms are quite good at what they do but what they do is very limited. Single celled organisms cannot grow very large, because as size increases proportionately less of a cell is exposed to the external environment in relation to its volume and the proportion of surface area decreases. Transferring materials from the exterior to the interior becomes less efficient. Multicell organisms live longer, since cells can be replaced and more offspring can be produced. Cells have increased functional efficiency when they are specialized into organs with specific capabilities.

Population Growth?

Population growth is the increase in the number of individuals in a population. Global human population growth amounts to around 83 million annually, or 1.1% per year. OR In the presence of abundant resources, populations can grow at geometric or exponential rates, Population growth by organisms with nonoverlapping generations can be described by the geometric model of population growth, Population growth that occurs as a continuous process, as in human or bacterial populations, can be described by the exponential model of population growth.

Difference between replication, transcription and translation.

Replication: Replication is the process by which DNA is copied to produce identical DNA molecules. It ensures genetic information is passed from cell to cell and generation to generation.

Transcription: Transcription is the process of converting a DNA sequence into messenger RNA (mRNA). It involves RNA polymerase synthesizing mRNA from the DNA template, carrying the genetic code from the nucleus to the ribosome.

Translation: Translation is the process where ribosomes synthesize proteins using the mRNA sequence. Transfer RNA (tRNA) brings amino acids to the ribosome, matching codons on the mRNA to form a polypeptide chain.

Recombination: The exchange of genetic material between different DNA molecules, creating genetic diversity.