BIOA01 - Deck 4 - Q151~Q194

Question 1

Describe the example of Anolis lizards in the Caribbean.
How is this an example of convergent evolution?

Answer 1

Anolis lizards in the Caribbean are different species; they still develop similar traits, (like sticky toe pads for climbing trees), due to their environment.
Convergent evolution is when organisms that do not share a recent common ancestor become alike due to their habitat.

Question 2

What was the Cambrian explosion?

Briefly describe what occurred with respect to animal marine life from 541-530 mya.

What were some key innovations?

What is the significance of the Burgess Shale in British Columbia?

Answer 2

The Cambrian explosion occurred from 541 to 530 mya.

Rapid and diverse evolution of marine animal life took place.

This explosion featured the emergence of many major animal groups and key innovations like hard exoskeletons and complex sensory organs.

The Burgess Shale in British Columbia is significant because it preserves exceptionally well-preserved fossils from this time, providing insight into the early evolution of complex life forms.

Question 3

What is mass extinction?
How many mass extinctions has Earth experienced?

Answer 3

Mass extinction is when a significant number of different species on Earth die out in a short period of time.
Earth has experienced five major mass extinctions in its history.

Question 4

How does background extinction relate to mass extinction?

Answer 4

Background extinction is the ongoing, slow rate of species extinction that occurs naturally over time, while mass extinction is a sudden event that leads to a significant & quick loss of species.

Question 5

What was notable about the Permian-Triassic (aka end-Permian) mass extinction?

Answer 5

The Permian-Triassic mass extinction was the most severe mass extinction event in Earth’s history.
It resulted in the loss of approx. 96% of all marine species and approx. 70% of terrestrial vertebrate species.

Question 6

What was notable about the Cretaceous-Paleogene (aka K-Pg) mass extinction?

Answer 6

The Cretaceous-Paleogene mass extinction occurred around 66 million years ago.
It caused the extinction of the dinosaurs and many other species due to a catastrophic event; (thought to be an asteroid impact).

Question 7

Why does adaptive radiation often follow mass extinction?

Answer 7

Mass extinctions create vacant ecological niches, allowing surviving species to rapidly diversify and adapt to occupy these newly available habitats, leading to adaptive radiation.

Question 8

Why are we now considered to be in the “Age of Mammals”?
Why was the time leading up to the K-Pg extinction considered to be the “Age of Reptiles”?

Answer 8

We are now in the “Age of Mammals” because mammals have become the dominant group of animals on Earth.
The time leading up to the K-Pg extinction was considered the “Age of Reptiles” because dinosaurs and other reptiles were the dominant land animals during that period.

Question 9

Why do many consider us to be in a period of the 6th mass extinction?
Why does Prof. Fitzpatrick often say that humans have been the worst thing to happen to the Earth?

Answer 9

Many scientists believe we are in the 6th mass extinction due to the rapid loss of species caused by human activities such as habitat destruction and climate change.
Prof. Fitzpatrick’s statement highlights the significant impact of human actions on Earth’s biodiversity.

Question 10

What are the eukaryotes?

Answer 10

Eukaryotes are organisms with a “true” nucleus enclosed in a membrane, (plants, animals, and fungi), while prokaryotes, (bacteria), lack this feature.

Question 11

What are protists?
Why do they form a paraphyletic group?

Answer 11

Protists are diverse, usually unicellular eukaryotic microorganisms that form a paraphyletic group because they include all eukaryotes that are NOT animals, plants, or fungi, making them a mixed group with no common evolutionary ancestor.

Question 12

Why is it important to study protists?

Answer 12

Studying protists is important because they are a diverse group of microorganisms that play crucial roles in ecosystems, can cause diseases, and offer insights into early evolutionary history.

Question 13

Why are protists not prokaryotes?

Answer 13

Protists are eukaryotes because they have cells with a nucleus and membrane-bound organelles, whereas prokaryotes lack these features.

Question 14

Why are protists different from plants and animals?

Answer 14

Protists are different from plants and animals because they are a diverse group of single-celled/simple multicellular organisms that differ from plants and animals in their diversity of structures, modes of locomotion, and nutritional strategies.

Question 15

What is the protist that causes malaria?
How is it transferred to humans?

Answer 15

The protist that causes malaria is Plasmodium.
It is transferred to humans through the bite of infected female Anopheles mosquitoes.

Question 16

Describe the events in the origin of eukaryotic cells.

Answer 16

Eukaryotic cells likely originated through a process called endosymbiosis, where simpler prokaryotic cells engulfed and formed mutually beneficial relationships with other cells, leading to the development of structures like mitochondria and chloroplasts within the eukaryotic cell.

Question 17

What is endosymbiosis?

Answer 17

Endosymbiosis is like a “living together” partnership where one organism lives inside another, benefiting both.
For example, the relationship between mitochondria and our cells.

Question 18

Describe the general steps in the primary endosymbiosis of mitochondria.

Answer 18

In primary endosymbiosis, a eukaryotic cell engulfs a free-living bacterium, forming a mutually beneficial relationship where the engulfed bacterium becomes the mitochondria over time.

Question 19

Describe the general steps in the secondary endosymbiosis of chloroplasts.

Answer 19

In secondary endosymbiosis, a eukaryotic cell engulfs a photosynthetic eukaryote, forming a symbiotic relationship where the engulfed organism becomes a chloroplast within the host cell.

Question 20

Describe how mitochondria are consistent with the endosymbiosis theory.

Answer 20

Mitochondria support the endosymbiosis theory because they have their own DNA, replicate independently within cells, and resemble free-living bacteria, suggesting they were once ancient bacteria engulfed by host cells.

Question 21

Describe the typical structures of protists using the Paramecium.

Answer 21

Paramecium is a ciliated protist with a characteristic slipper-like shape, covered in cilia for movement. It has a macronucleus for general cell functions and a micronucleus for genetic exchange.

Question 22

What is ingestive feeding?

Answer 22

Ingestive feeding is a method of obtaining nutrients in which organisms engulf and digest other particles or organisms.

Question 23

How do protists move?

Answer 23

Protists move using whip-like structures called flagella, hair-like structures called cilia, or by constantly changing their cell shape through pseudopodia (false feet).

Question 24

How do protists reproduce?
Describe the similarities between a haploid-dominated life cycle and a diploid-dominated life cycle.

Answer 24

Protists can reproduce asexually (binary fission) and sexually (conjugation).
The similarity between the two life cycles is that they both involve haploid and diploid stages, which alternate in the life cycle, with meiosis and fertilization occurring at different points.

Question 25

What are the Opisthokonts? What is a common feature of all opisthokonts (at some stage in their life cycle)?

Answer 25

Opisthokonts are a group of eukaryotes that includes animals, fungi, and choanoflagellates. A common feature is a posterior flagellum or a flagellated stage in their life cycle.

Question 26

What are the Amoebozoans? Describe two examples.

Answer 26

Amoebozoans are a group of protists characterized by amoeboid movement. Examples include Amoeba and Dictyostelium

Question 27

What are the Archaeplastids? Describe some general features and their notable representatives.

Answer 27

Archaeplastids are a group of protists that gave rise to plants. They have chloroplasts and include green algae and land plants.

Question 28

Describe some similarities and differences between green algae and land plants.

Answer 28

Both green algae and land plants are photosynthetic and have chloroplasts.

Land plants have adaptations for terrestrial life, such as a waxy cuticle and specialized reproductive structures.

Question 29

What are the Stramenopiles? Describe some general features and their notable representatives.*

Answer 29

Stramenopiles are a diverse group of protists with hairy flagella. Notable representatives include diatoms and brown algae.

Question 30

What is notable about kelp forests?

Answer 30

Kelp forests are underwater ecosystems dominated by large brown algae. They provide habitat and food for a wide range of marine species.

Question 31

What are the Alveolates? Describe some general features and their notable representatives.

Answer 31

Alveolates are a group of protists with small sacs (alveoli) beneath their cell membrane. Notable representatives include the dinoflagellates and ciliates

Question 32

What are the Excavates? Describe some general features and their notable representatives.

Answer 32

Excavates are a diverse group of protists known for their modified feeding and flagellar structures. Notable representatives include Euglena and Trypanosoma.

Question 33

What is notable about Euglena gracilis, Trypanosoma brucei and T. cruzi, Giardia lamblia, and Trichomonas vaginalis?

Answer 33

• Euglena gracilis is a photosynthetic protist.
• Trypanosoma brucei and T. cruzi are parasitic kinetoplastids.
• Giardia lamblia is a parasitic diplomonad.
• Trichomonas vaginalis is a parasitic parabasalid.

Question 34

What is evo-devo?

Answer 34

Evo-devo, or evolutionary developmental biology, is a field that explores how changes in developmental processes contribute to evolutionary changes.

Question 35

Why do early human embryos produce a tail and gill slits?*

Answer 35

Early human embryos produce these structures as remnants of their evolutionary history, reflecting shared ancestry with fish-like ancestors.

Question 36

What are the homeotic genes?

Answer 36

Homeotic genes are master regulatory genes that control the development of specific body structures during embryonic development.

Question 37

Why are the Hox genes considered to be the “genetic toolkit”?

Answer 37

because they regulate the development of body segments in animals and are highly conserved across species.

Question 38

How do the Hox genes represent evolutionary conservation of gene sequence and gene function?

Answer 38

Hox genes are similar in sequence and function across diverse animal species, indicating their ancient origins and essential role in shaping animal body plans.

Question 39

What is a teratogen?

Answer 39

A teratogen is an agent that can cause birth defects or abnormalities in the development of an embryo or fetus.

Question 40

What happens if you mutate Hox genes? Describe examples using Antennapedia and Ultrabithorax.

Answer 40

Mutations in Hox genes can result in developmental abnormalities. For example, in fruit flies, mutations in Antennapedia can cause legs to grow in place of antennae, and Ultrabithorax mutations can lead to the transformation of one body segment into another.

Question 41

Why is there sexual conflict in water striders?

Answer 41

Sexual conflict in water striders arises because males benefit from frequent mating, while females may suffer physical harm or reduce future reproductive potential from excessive mating.

Question 42

Why did the researchers turn to Distal-less (Dll)?

Answer 42

Researchers turned to the Distal-less gene (Dll) to study its role in wing development and evolutionary changes in wing morphology.

Question 43

How did their genetic manipulations confirm a role for Dll?

Answer 43

Genetic manipulations showed that altering Dll expression in butterflies affected wing patterns, confirming its role in wing development.

Question 44

What role does Dll play in Bicyclus butterflies?

Answer 44

Dll plays a crucial role in determining wing patterns and mimicry in Bicyclus butterflies.