Week 4 Notes

Question 1

Why are protists no longer considered a kingdom?

Answer 1

Protists are in all super groups
They are a paraphyletic taxon

Question 2

What do all protists have in common

Answer 2

They all contain eukaryotic cells and a nucleus
Can reproduce sexually

Question 3

Giardia Intestinalis

Answer 3

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

Question 4

Euglena

Answer 4

Member of excavata and photosynthetic

Question 5

Dinoflagellates

Answer 5

Produce toxin that can cause paralytic shellfish poisioning
- High amounts can cause harmful algae bloom known as the red tide
Belong to (Chromalveolata)

Question 6

Why are some algaes green and others red or brown?

Answer 6

Growing at different water depths
Pigment adaptation to light waves that penetrate the water
Producing different amounts of oxygen

Question 7

6 eukaryotic groups with complex muticellular organisms

Answer 7

Animals
Plants
Fungi
Green, Brown and Red algae

Question 8

Advantage of muticellularity

Answer 8

Allowing them to grow larger

Question 9

Good and bad traits of organisms

Answer 9

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

Question 10

The role RNA may have played in the early steps leading to life:

Answer 10

Store genetic information and act as a catalyst for biochemical reactions

Question 11

Differentiate between geochemical, fossil, and genetic evidence:

Answer 11

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

Question 12

Modes of metabolism in prokaryotes

Answer 12

Aerobic: Uses oxygen
Anaerobic: Uses other molecules instead of oxygen

Question 13

Differentiate between transformation, transduction, and conjugation:

Answer 13

Transformation: Prokaryotes take up Free DNA in their environment

Transduction: Bacteriophages transfer DNA between bacteria

Conjugation: Direct transfer of DNA between 2 bacteria

Question 14

Why horizontal gene transfer makes it difficult to predict evolutionary relationships:

Answer 14

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).

Question 15

Several important roles of prokaryotes in ecosystems:

Answer 15

Decomposers: breaking down dead organic matter
Nitrogen Fixation: converting nitrogen into forms that are usable by plants
Photosynthesis: contribute to oxygen production

Question 16

What caused the “oxygen revolution”

Answer 16

When cyanobacteria generated large amounts of oxygen through photosynthesis which then was released into the atmosphere

Question 17

Why the oxygen revolution was catastrophic for some organisms and beneficial for others:

Answer 17

Because there are many anaerobic organisms which oxygen to them are toxic

Question 18

What is a mutualistic relationship? Give an example:

Answer 18

Where both organisms benefit

Rhizobia bacteria and leguminous plants—bacteria fix nitrogen for the plant, and the plant provides nutrients to the bacteria.

Question 19

Mechanisms that allow extremophiles to cope in extreme conditions:

Answer 19

Protein adaptations: Resist denaturation
Membrane stability: through unique lipid compositions
Enzymes: functioning in extreme environment

Question 20

Why halophiles like halobacteria can cope with high salt concentrations:

Answer 20

Halophiles have specialized proteins and cell membrane adaptations that allow them to maintain osmotic balance and prevent dehydration in hypersaline environments

Question 21

Evaluate the advantages and disadvantages of sexual reproduction and explain why sexual reproduction is common in eukaryotes.

Answer 21

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

Question 22

Diploid Dominant, Haploid dominant, Haplodiplontic

Answer 22

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).

Question 23

Plasmodium

Answer 23

Parasite that causes malaria belonging to chromalveolata

Question 24

Paramecium

Answer 24

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.

Question 25

Colpoda

Answer 25

ciliates
survive unfavourable conditions
such as dehydration, heat and cold by forming
resting cysts

Question 26

Brown Algae

Answer 26

Chromalveolata

Question 27

Relationships between Fungi and Eukaryotes

Answer 27

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

Question 28

Characteristics shared by Fungi

Answer 28

Chemoheterotrophs

Question 29

One characteristic for each of the 5 phyla of fungi

Answer 29

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

Question 30

Examples of mushrooms and their phyla

Answer 30

Rhizopus (bread mold)
- Zygomycota
Saccharomyces (yeast)
- Ascomycota
Amanita (mushroom)
- Basidiomycota

Question 31

Differences between parasites, symbionts, and decomposers

Answer 31

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

Question 32

Two symbiotic relationships

Answer 32

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

Question 33

How did fungi help early plants on land

Answer 33

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