Week 4 Notes Flashcards
Why are protists no longer considered a kingdom?
Protists are in all super groups
They are a paraphyletic taxon
What do all protists have in common
They all contain eukaryotic cells and a nucleus
Can reproduce sexually
Giardia Intestinalis
A proteist that belongs to a unicellular group called doplomonads which is in the supergroup Excavata
They are protists that live in lakes and river that makes people ill (beaver fever) if digested
Euglena
Member of excavata and photosynthetic
Dinoflagellates
Produce toxin that can cause paralytic shellfish poisioning
- High amounts can cause harmful algae bloom known as the red tide
Belong to (Chromalveolata)
Why are some algaes green and others red or brown?
Growing at different water depths
Pigment adaptation to light waves that penetrate the water
Producing different amounts of oxygen
6 eukaryotic groups with complex muticellular organisms
Animals
Plants
Fungi
Green, Brown and Red algae
Advantage of muticellularity
Allowing them to grow larger
Good and bad traits of organisms
Quick growth and development = Smaller size and shorter life span
Slow growth and development = Larger size and long life span
Short life span, many offspring = no care for offspring
Long life span, few offspring = extensive care for offspring
The role RNA may have played in the early steps leading to life:
Store genetic information and act as a catalyst for biochemical reactions
Differentiate between geochemical, fossil, and genetic evidence:
Geochemical
- Chemical signatures in rocks that suggest early life
Fossil
- Physical remnants of ancient organisms provide insight into early life forms
Genetic evidence
- Comparisons of DNAs and RNAs amongst living organisms to reconstruct evolutionary relationships of early life forms
Modes of metabolism in prokaryotes
Aerobic: Uses oxygen
Anaerobic: Uses other molecules instead of oxygen
Differentiate between transformation, transduction, and conjugation:
Transformation: Prokaryotes take up Free DNA in their environment
Transduction: Bacteriophages transfer DNA between bacteria
Conjugation: Direct transfer of DNA between 2 bacteria
Why horizontal gene transfer makes it difficult to predict evolutionary relationships:
Horizontal gene transfer allows genes to move between species, blurring the lines of descent and making it harder to trace evolutionary relationships through vertical inheritance (parent to offspring).
Several important roles of prokaryotes in ecosystems:
Decomposers: breaking down dead organic matter
Nitrogen Fixation: converting nitrogen into forms that are usable by plants
Photosynthesis: contribute to oxygen production
What caused the “oxygen revolution”
When cyanobacteria generated large amounts of oxygen through photosynthesis which then was released into the atmosphere
Why the oxygen revolution was catastrophic for some organisms and beneficial for others:
Because there are many anaerobic organisms which oxygen to them are toxic
What is a mutualistic relationship? Give an example:
Where both organisms benefit
Rhizobia bacteria and leguminous plants—bacteria fix nitrogen for the plant, and the plant provides nutrients to the bacteria.
Mechanisms that allow extremophiles to cope in extreme conditions:
Protein adaptations: Resist denaturation
Membrane stability: through unique lipid compositions
Enzymes: functioning in extreme environment
Why halophiles like halobacteria can cope with high salt concentrations:
Halophiles have specialized proteins and cell membrane adaptations that allow them to maintain osmotic balance and prevent dehydration in hypersaline environments
Evaluate the advantages and disadvantages of sexual reproduction and explain why sexual reproduction is common in eukaryotes.
Produces genetic variation, increasing the likelihood of survival in changing environments.
Can combine beneficial traits from two parents.
Disadvantages:
Generally slower and more energy-intensive than asexual reproduction.
Despite the disadvantages, sexual reproduction promotes genetic diversity, which is crucial for adapting to new challenges
Diploid Dominant, Haploid dominant, Haplodiplontic
Diploid dominant The diploid stage (2n) is the main, long-lasting stage, with the organism primarily existing in this form (e.g., most animals).
Haploid-dominant: The haploid stage (n) is the main form of the organism, with the diploid stage being brief (e.g., many fungi and some algae).
Haplodiplontic (alternations of generations): Organisms alternate between a haploid phase (gametophyte) and a diploid phase (sporophyte), with both stages being multicellular (e.g., plants).
Plasmodium
Parasite that causes malaria belonging to chromalveolata
Paramecium
a ciliate
which belongs to
Chromalveolata
have specialized
cellular structures which allow them to carry out
specialized functions, e.g. movement, ingestion,
reproduction, metabolism and response to the
environment.
Colpoda
ciliates
survive unfavourable conditions
such as dehydration, heat and cold by forming
resting cysts
Brown Algae
Chromalveolata
Relationships between Fungi and Eukaryotes
Fungis are closely related to protists (Nucleariids) which are unicellular amoebae
Fungi’s cell wall is made out of chitin
Fungi store Carbohydrates as glycogen
Characteristics shared by Fungi
Chemoheterotrophs
One characteristic for each of the 5 phyla of fungi
Chytridiomycota
Disperse flagellated zoospores
Zygomycota
Reproduce sexually using zygosporangia
Glomeromycota
Form endomycorrhizal by penetrating plant root cells
Ascomycota
Produce sexual spores in sac-like structures called asci
Basidiomycota
Have dikaryotic stage (2 haploid nuclei per cell) during sexual reproduction
Examples of mushrooms and their phyla
Rhizopus (bread mold)
- Zygomycota
Saccharomyces (yeast)
- Ascomycota
Amanita (mushroom)
- Basidiomycota
Differences between parasites, symbionts, and decomposers
The parasite feeds on living organisms (host) harm it
Symbiont engages in a mutualistic relationship where both organisms benefit
Decomposer feeds on dead organic material and breaks it down
Two symbiotic relationships
Lichen
- fungus and algae where the fungus provides protection and the algae supplies glucose
Mycorrhizae
- fungi and plant roots where fungi help absorb water and nutrients and plants supply carbohydrates
How did fungi help early plants on land
Forming mutualistic relationships
with algae and cyanobacteria helping to colonize poor soil
Created symbiosis with early plant roots to assist in plant roots with water and nutrient absorption
Broke down rocks decomposition releasing nutrients and soil formation
