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Ecology of Algae and Prokaryotes: Diversity, Evolution, and Symbiosis, Exams of Biology

A comprehensive overview of the ecology and evolution of algae and prokaryotes, covering topics such as the similarities between algae and plants, the mechanisms that generate biological diversity, the characteristics of eukaryotes and prokaryotes, the benefits of being small, the evolution of photosynthesis, the importance of viruses, the features that distinguish bacteria from archaea, and the evidence supporting the hypothesis that life evolved in deep-sea thermal vents. The document also explores the diversity and distinctive features of fungi, the evolution of alternation of generations, and the symbiotic relationships between algae and fungi. With a focus on understanding the fundamental principles and processes that underlie the diversity of life, this document could be a valuable resource for students and researchers in the fields of biology, ecology, and evolutionary biology.

Typology: Exams

2023/2024

Available from 08/27/2024

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BIOL 200 Midterm | 100% Correct Answers |
Verified | Latest 2024 Version
The ecology of algae in aquatic ecosystems parallels that of plants in terrestrial ecosystems. Make three
points to support this statement. - ✔✔
Aglae and mosses/plants have similar features such as:
- branched apical growth
- cuticles
- asymmetrical flagellated cells
- cellulose, thylakoids, chlorophyll b, some have 2 flagella...
If some Euglenoids have the same pigment as green algae and higher plants, why are they not so closely
related? - ✔✔secondary endosymbiosis
Why evolve towards a substantial part of the cycle being diploid phase? - ✔✔- most of life cycle is in
gametic meiosis in the diploid phase and this permits diversity
- heterozygosity occurs in this phase
- all genes expressed in haploid phase are subject to selection and mutation but reduction in this phase
leads to protection of the gene.
-decrease in haploid phase reduces the uv or other fatal factors affecting the gene
Describe the primary and secondary mechanisms that generate biological diversity across the tree of life
- ✔✔Primary: natural and sexual selection based on the combination of genetic mutation and
environmental/spatial and temporal heterogeneity
Secondary: features and impacts of diversity that generate more diversity so development of more
structures, colonization, development of more advanced reproductive systems, interactions...
What are some structural differences between prokaryotes and eukaryotes? - ✔✔Eukaryotes have:
-dna in nucleus
- membrane bound organelles
-cytoskeleton
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BIOL 200 Midterm | 100% Correct Answers |

Verified | Latest 2024 Version

The ecology of algae in aquatic ecosystems parallels that of plants in terrestrial ecosystems. Make three points to support this statement. - ✔✔ Aglae and mosses/plants have similar features such as:

  • branched apical growth
  • cuticles
  • asymmetrical flagellated cells
  • cellulose, thylakoids, chlorophyll b, some have 2 flagella... If some Euglenoids have the same pigment as green algae and higher plants, why are they not so closely related? - ✔✔secondary endosymbiosis Why evolve towards a substantial part of the cycle being diploid phase? - ✔✔- most of life cycle is in gametic meiosis in the diploid phase and this permits diversity
  • heterozygosity occurs in this phase
  • all genes expressed in haploid phase are subject to selection and mutation but reduction in this phase leads to protection of the gene.
  • decrease in haploid phase reduces the uv or other fatal factors affecting the gene Describe the primary and secondary mechanisms that generate biological diversity across the tree of life
  • ✔✔Primary: natural and sexual selection based on the combination of genetic mutation and environmental/spatial and temporal heterogeneity Secondary: features and impacts of diversity that generate more diversity so development of more structures, colonization, development of more advanced reproductive systems, interactions... What are some structural differences between prokaryotes and eukaryotes? - ✔✔Eukaryotes have:
  • dna in nucleus
  • membrane bound organelles
  • cytoskeleton
  • flagella
  • larger ribosomes
  • chromosome pairs Why do people call viruses borrowed life? - ✔✔they can grow provide and produce but only with a host. They are not able to generate life on their own. What is a thermophilic environment? - ✔✔alkaline environment often found in deep sea vents protected from UV it is extremely harsh/hot environment. What are some biological characteristics of prokayrotes? - ✔✔surface area to volume ratio is important, they are unicellular, one double stranded circular chromosome, lack nucleus, no sexual reproduction What are some benefits to being 'so small?' - ✔✔- intimate contact with surroundings
  • high rate of living
  • rapid reproduction
  • boom and bust
  • but water is viscous (neg) List the four steps of fission - ✔✔1. duplication of circular chromosome
  1. cell elongation
  2. ingrowth of plasma membrane
  3. ingrowth of cell wall What are 3 reasons for prokaryotic success in early earth? - ✔✔- small size
  • rapid generation time
  • prolonged dormancy
  • diverse mechanisms
  • they can produce water though metabolism Why is there a trend in extended diplomatic stage in advanced fungi? - ✔✔- if there was no gap between haploid and diploid stage it would be alternation of generation
  • may generate variability
  • greater potential for phenotypic variability and evolutionary adaptation to changing environment
  • enhanced capacity to create genetic variability between 2 nuclei during cell duplication What is symbiosis and what is one example of a parasitic and mutualistic relationship? - ✔✔- close long term allocation with organisms between difference species
  • coral reefs and algae (mutual)
  • ticks on dogs (parasitic) How were lichens and mycorrhizae likely essential for plants to colonize land? - ✔✔- terrestrial earth was bare and rocky not a lot of water available
  • abundant light and co
  • lichen initiated development of soil organic matter that stores and supplies nutrients and water
  • mychorrhizae lead evolution of roots with branched system that possibly led to stems leaves epidermis, etc etc Structure usually relates to function in living organisms. Provide three distinct examples from prokaryotic organisms to illustrate this concept. - ✔✔Flagellum - motility; Thick cell wall membrane (esp. Gram positives) to resist desiccation; Endospore development to survive periods of unfavourable environmental conditions; Granules (inclusion bodies) for storage of food reserves Describe two lines of evidence supporting the hypothesis that life evolved in deep sea thermal vents - ✔✔a) Thermophiles are particularly frequent at the base of the Tree of Life b) The reducing conditions in vents are consistent with the biochemistry of early life forms (heterotrophic, and anaerobic)

c) Most of the fundamental housekeeping (cellular maintenance) proteins and biochemical processes seem to have a heritage reflecting a hydrothermal environment d) UV levels are low in vents relative to the ocean surface meaning nucleic acid degradation was minimal Briefly explain two different reasons why the evolution of photosynthesis in the cyanobacteria is believed to have been critical to the subsequent development of the diversity of life on Earth (2 x 2 marks). - ✔✔1)Ozone development (O3) associated with an oxygenic atmosphere meant that the organisms at the top of the land or aquatic surfaces were better protected against UV radiation.

  1. Endosymbiosis of cyanobacteria led to the evolution of the first and most photosynthetic eukaryotes. The biology of viruses is important to human societies in many different ways. Give three examples to demonstrate this point. - ✔✔a) Smallpox led to the development of vaccines as a preventative medical procedure. b) Viruses such as phages are very important tools in molecular biology. c) Viruses cause many serious human diseases.(AIDS, influenza) Provide 2 reasons to explain why prokaryotes are generally only metabolically active when their cells are in contact with external water. - ✔✔a) diffusion can supply nutrients and organic matter b) diffusion will remove waste excretions c) water is necessary as a metabolite Give three distinct reasons why viral diseases can evolve rapidly. - ✔✔a) Rapid reproduction in host cell b) Nucleic acid mutations during replication cause antigenic drift. c) Nucleic acid reassortment can occur when two strains infect the same cell (antigenic shift). Explain what is meant by the term chemoautotroph, and provide an example illustrating their role in a biogeochemical cycle. - ✔✔A chemoautotroph obtains its energy obtained by chemical oxidation of a reduced compound such as Fe2+, NH4+, S, CH4, and its by reducing CO2 gas to an organic compound such as carbohydrates.
  • Chemoautotrophs have globally significant and critically important impacts on the biogeochemical cycling of iron, nitrogen, and carbon cycles

A chickadee, a caterpillar, a chanterelle and a cedar are all believed to have evolved from a common pool of ancestral prokaryotes. List four types of evidence to support this hypothesis: - ✔✔a) Nucleic acid mechanism of heredity b) Nucleic acid code c) Cellular organizational patterns d) Energy transformations based on ATP currency Explain two lines of evidence indicating that some Euglenoids gained the capacity to photosynthesize by secondary endosymbiosis? - ✔✔Chloroplasts in the photosynthetic euglenoids were acquired through (secondary) endosymbiosis by an ancestral heterotrophic euglenoid host of an ancestral green algal cell that itself was a result of (primary) endosymbiosis by an ancestral heterotrophic eukaryotic host of a cyanobacterium that became an ancestral chloroplast. Dry rot' refers to decomposition of wood in a dry environment by certain fungi but not by bacteria. Explain two distinctive features of fungi that allow them to achieve this process? - ✔✔a) Capacity to translocate water and nutrients along the mycelium from hyphae that are in contact with moist areas to hyphae that are actively decomposing wood in dry areas. b) Certain dry rot fungi can synthesise water as a byproduct of glycolysis c) Synthesize specialised wood-decaying enzymes

  1. Compare and contrast fungal and vascular plant reproduction by describing three distinctive features of the genetics and lifecycles of the Kingdom Fungi. - ✔✔a) Sexual reproduction is by zygotic meiosis in most fungi whereas vascular plants have alternation of generations. b) Zygotic (diploid) stage in fungi is unicellular and often represents the dormant highly protected stage of the life cycle that is favoured when environmental conditions are not favourable for growth. c) Cytoplasmic and nuclear fusion are substantially separated in time in many fungi meaning there is a distinct and prolonged dikaryotic phase. d) Asexual reproduction is common in most fungi, but a much smaller proportion of vascular plants.
  2. Indicate how lichens acquire their carbon and sulfur. - ✔✔Alga fixes CO2 during photosynthesis some of which is used for its own metabolism and some of which is translocated to the fungus. Sulfur is generally acquired from atmospheric deposition of particles and rainfall.