BT101 Final Term Past Papers Complete 2023 by Sulman Ali

BT101 - Ecology, Biodiversity & Evolution-I · Final-Term File 2023 By · SULMAN ALI (BS-ZOOLOGY)

What is ecological niche.

An ecological niche describes how a species lives and interacts with other organisms in a habitat. It can be thought of as the role or job that a species has in nature.

Characters of Bacteria:

Bacteria play many roles in our ecosystem. Bacteria are decomposers which break down dead material and recycle it. By decomposing dead organic matter, they contribute to soil structure and the cycles of nature. Bacteria provide nutrients like nitrogen and phosphorus to plants as well as to produce growth hormones. They are also needed for the carbon and nitrogen cycles.

Layers of atmosphere and their heights:

•  Exosphere: 700 to 10,000 km (440 to 6,200 miles)
•  Thermosphere: 80 to 700 km (50 to 440 miles)
•  Mesosphere: 50 to 80 km (31 to 50 miles)
•  Stratosphere: 12 to 50 km (7 to 31 miles)
•  Troposphere: 0 to 12 km (0 to 7 miles)

What is limits selection:

1= Evolution requires genetic variation 2= Gene interactions affect fitness of alleles 3= Genes have multiple effects.

Structure and Function of Golgi Apparatus.

Structure:

It is Located near the end of the ER close to the nucleus and Composed of several layers of cisternae (fluid-filled sacs) • It Has three different parts: 1. cis-Golgi 2. medial-Golgi 3. transGolgi

Functions:

1= cis is first cisternae. 2= trans is final cisternae. 3= From trans, proteins are packaged into vesicles destined to lysosomes, secretory vesicles, or the cell surface. Transport vesicles are used to move back and forth between the ER and Golgi bodies 4= One side of the Golgi body receives transport vesicles produced by the ER. 5= This side is called cis face. 6= Opposite side releasing vesicle is trans face.

What is the difference between Analogy & homology?

Homology:

Homology involves the study of organs that have evolved from same origin or from common ancestor but have different functions. It is a Divergent evolution.

For example:

•  Wings of bat and Hands of humans.

Analogy:

Analogy involves the study of organs that are evolved from different ancestors but perform a similar function. It is a Convergent Evolution.

For example:

•  Wings of bat and wings of insects.

Flow of Energy in Ecosystem Feeding Levels: or Explain Feeding level of organisms:

•  Food energy passes through different sequence.
•  Example: plants → grass hopper → frog → snake → hawk
•  Many plant species eaten by insects
•  Many insects species eaten by frogs
•  this complexity is organized by ecologists.
•  Recognized limited number of feeding or trophic levels
•  In Food Chain
•  Food energy passes through different sequence.
•  Level 1: Primary producer
•  Level 2: Primary consumer
•  Level 3: Secondary consumer
•  Level 4: Tertiary Consumer Level
•  5: Apex Predator

Reproduction in arthropods?

Arthropods reproduce by sexual reproduction, which involves the generation and fusion of gametes. Most arthropods are either male or female, and they undergo internal fertilization. Once

Homology

Analogy

In biology, homology is the resemblance of the arrangement, physiology, or growth of various species of organisms. In biology, an analogy is a functional similarity of structure, based on the similarity of use and not upon common evolutionary origins.

Due to a similar structure, they do have similar functions Due to different structures, they do not have similar functions.

Homologous structures are inherited from a common precursor. Analogous structures are inherited from a different precursor.

Homologous structures are developed from related embryonic substances. Homology is developed in species that are not related to each other.

Homology happens due to divergent evolution. Analogy happens due to convergent evolution the egg has been fertilized, the female usually lays the egg, and it continues developing outside of the mother’s body.

Reproductive System:

1= Mostly dioecious 2= Paired genital opening 3= Male often packages sperm in a spermatophore 4= Transfer them into the female genital tract 5= Copulation occurs. 6= Sperms are transferred via modified pedipalp.

What is autolysis and putrefaction:

Autolysis: Breaking down of tissues by the body's own internal chemicals and enzymes

Putrefaction: Breakdown of tissues by bacteria. And releases compounds such as cadaverine and putrescine causing decaying odor.

Write a note on rate of evolution:

The rate of evolution is quantified as the speed of genetic or morphological change in a lineage over a period of time. The speed at which a molecular entity (such as a protein, gene, etc.) evolves is of considerable interest in evolutionary biology.

Carbon cycle:

•  Carbon enters the atmosphere as CO2.
•  CO2 is absorbed by autotrophs such as green plants.
•  Animals consume plants, thereby, incorporating carbon into their system.
•  Animals and plants die, their bodies decompose and carbon is reabsorbed back into the atmosphere.

Exponential growth and Logistic growth.

Exponential growth Logistic growth It occurs when resources are abundant It occurs when resources are limited Population passes well beyond the carrying capacity of the ecosystem Population doesn’t grow beyond the carrying capacity of the ecosystem It produce J shaped curve It produce S shaped curve A stationary or stable phase is completely achieved A stationary or stable phase is achieved

It has two phases lag and log It has four phases lag, log, deceleration and steady It occurs in fewer organisms like lemmings etc. It is more common in wildlife, yeast etc.

DN/dt=Nr N= population size, r= intrinsic rate DN/dt= rN(k-N)/K DN/dt= change in population size per unit time K= carrying capacity

Characteristics of Archaea:

The common characteristics of Archaebacteria known to date are these: 1= the presence of characteristic tRNAs and ribosomal RNAs; 2= the absence of peptidoglycan cell walls, with in many cases, replacement by a largely proteinaceous coat; 3= the occurrence of ether linked lipids built from phytanyl chains. 4= Most don’t need oxygen to survive 5= They can produce ATP from sunlight 6= They can survive enormous temperature and pressure extremes. 7= They can survive high doses of radiation 8= They can survive under rocks and in ocean floor vents deep below the ocean’s surface.