Chapter 3: Classification and Biodiversity

Question 1

3.1 Classification

What is biodiversity and why is it important?

Answer 1

Biodiversity is the measure of variety in living organisms and their genetic differences. It helps monitor population changes and understand the relationships between organisms.

Question 2

3.1 Classification

Why is classification necessary in biology?

Answer 2

Classification provides a standardized system for identifying organisms, tracking population changes, and understanding evolutionary relationships.

Question 3

3.1 Classification

What are the main taxonomic groups from largest to smallest?

Answer 3

Domain, kingdom, phylum (division for plants), class, order, family, genus, species.

Question 4

3.1 Classification

What are the two parts of a binomial name, and how are they written?

Answer 4

The genus (capitalized) and the species (lowercase), both written in italics, e.g., Homo sapiens.

Question 5

3.1 Classification

What are the three domains into which all living organisms are classified?

Answer 5

Archaea, Bacteria, and Eukaryota.

Question 6

3.1 Classification

What is the only kingdom in the Archaea domain, and what are its characteristics?

Answer 6

Archaebacteria – Ancient bacteria thought to be early relatives of eukaryotes, initially believed to exist only in extreme environments but now found everywhere, especially in soil.

Question 7

3.1 Classification

What is the only kingdom in the Bacteria domain, and what are its characteristics?

Answer 7

Eubacteria – True bacteria that include disease-causing species and beneficial bacteria aiding digestion and nutrient recycling.

Question 8

3.1 Classification

What are the four eukaryotic kingdoms?

Answer 8

Protactista, Fungi, Plantae, and Animalia.

Question 9

3.1 Classification

What are the characteristics of Protactista?

Answer 9

A diverse group of microscopic organisms, including heterotrophs and autotrophs. Examples: Amoeba, Chlamydomonas, green and brown algae, and slime molds.

Question 10

3.1 Classification

What are the characteristics of Fungi?

Answer 10

All heterotrophs, mostly saprophytic with some parasitic species, containing chitin (not cellulose) in their cell walls.

Question 11

3.1 Classification

What are the characteristics of Plantae?

Answer 11

Mostly autotrophs, performing photosynthesis using chlorophyll. Examples: mosses, liverworts, ferns, gymnosperms, and angiosperms.

Question 12

3.1 Classification

What are the two parts of a binomial name, and how are they written?

Answer 12

The genus (capitalized) and the species (lowercase), both written in italics, e.g., Homo sapiens.

Question 13

3.1 Classification

Define species

Answer 13

A group of organisms with similar characteristics that interbreed to produce fertile offspring

Question 14

3.1 Classification

Explain the limitations of defining a species.

Answer 14

The definition of a species as a group of organisms with similar characteristics that interbreed to produce fertile offspring has limitations, as it can be difficult to assign organisms to a single species or identify new species.

Question 15

3.1 Classification

What are the advantages of the morphological species concept?

Answer 15

• Allows grouping based on observed characteristics.
• Useful when other data (e.g., genetic) is unavailable.

Question 16

3.1 Classification

What are the limitations of the morphological species concept?

Answer 16

• Sexual dimorphism may lead to misclassification.
• Environmental factors can influence appearance.
• Similar-looking species may not be related.

Question 17

3.1 Classification

What is the reproductive or biological species concept?

Answer 17

A species is defined as a group of organisms that interbreed to produce fertile offspring.

Question 18

3.1 Classification

What are the advantages of the biological species concept?

Answer 18

• Addresses sexual dimorphism issues.
• Provides a practical approach for classifying animals.

Question 19

3.1 Classification

What are the limitations of the biological species concept?

Answer 19

• Does not account for geographically separated populations.
• Hybrids (e.g., mules) are sterile despite shared characteristics.
• Less effective for plants that frequently interbreed with related species.

Question 20

3.1 Classification

What are the two more refined definitions under the biological species concept?

Answer 20

• A group of organisms that can potentially breed to produce fertile offspring.
• A group of organisms in which genes can flow between individuals.

Question 21

3.1 Classification

What is the ecological species model?

Answer 21

Defines species based on the ecological niche they occupy.

Question 22

3.1 Classification

What are the limitations of the ecological species model?

Answer 22

A species may occupy more than one niche.

Question 23

3.1 Classification

What is the mate-recognition species model?

Answer 23

Defines species based on unique fertilization and mating behaviors.

Question 24

3.1 Classification

What is a limitation of the mate-recognition species model?

Answer 24

Some species may interbreed with others but still remain distinct.

Question 25

# 3.1 Classification How does molecular biology contribute to species classification?

Answer 25

Uses DNA, RNA, and protein analysis to identify differences and relationships between species.

Question 26

# 3.1 Classification What is molecular phylogeny?

Answer 26

The study of evolutionary relationships using molecular data to classify species or the analysis of genetic material to determine evolutionary relationships. .

Question 27

# 3.1 Classification What are potential issues with molecular phylogeny?

Answer 27

It may create overly complex classifications and misinterpret relationships.

Question 28

# 3.1 Classification What is the genetic species model?

Answer 28

A species definition based on DNA evidence.

Question 29

# 3.1 Classification What are the challenges of the genetic species model?

Answer 29

* Deciding how much genetic difference defines a species. * Historically, DNA collection was expensive and time-consuming. * Although now faster and cheaper, defining species still requires clear thresholds.

Question 30

# 3.1 Classification What is the evolutionary species model?

Answer 30

A species definition based on shared evolutionary relationships and ongoing evolution.

Question 31

# 3.1 Classification What challenges are associated with the evolutionary species model?

Answer 31

Difficulties in identifying clear evolutionary pathways. Not always easy to apply to organisms with limited evolutionary records.

Question 32

# 3.1 Classification Why is DNA analysis becoming more important in species classification?

Answer 32

It allows for more precise definitions and better understanding of evolutionary relationships.

Question 33

# 3.1 Classification Why is traditional morphology still used in species classification?

Answer 33

It remains useful for basic identification when genetic data is unavailable.

Question 33

# 3.1 Classification What is a challenge in classifying hybrids?

Answer 33

Determining at what point hybrids should be considered a separate species.

Question 34

# 3.1 Classification Why can't reproduction-based models be used for all organisms?

Answer 34

Many organisms, such as bacteria, reproduce asexually, making reproductive criteria irrelevant.

Question 35

# 3.1 Classification Why is fossil classification challenging?

Answer 35

Fossils cannot reproduce or provide DNA, so classification relies on morphology alone.

Question 36

# 3.1 Classification What is sexual dimorphism?

Answer 36

A great deal of difference in appearance between male and female of the same species.

Question 37

# 3.1 Classification How can gel electrophoresis be used in classification?

Answer 37

Gel electrophoresis can be used to distinguish between species and determine evolutionary relationships by analyzing the DNA fragments of different organisms.

Question 38

# 3.1 Classification How does gel electrophoresis work?

Answer 38

DNA fragments are placed in a gel, an electric current is applied, and smaller fragments of the DNA move faster and farther than larger ones, making it easy to distinguish the DNA of one individual from another.

Question 39

# 3.1 Classification What are restriction enzymes used for in gel electrophoresis?

Answer 39

To cut DNA into fragments at specific sequences, creating pieces of different sizes for analysis.

Question 40

# 3.1 Classification What role does dye (e.g., ethidium bromide) play in gel electrophoresis?

Answer 40

It binds to DNA fragments, allowing them to be visualized under UV light.

Question 41

# 3.1 Classification What is the three-domain model of classification?

Answer 41

It divides life into Bacteria, Archaea, and Eukaryota, based on molecular and genetic differences.

Question 42

# 3.1 Classification How do Archaea differ from bacteria and eukaryotes?

Answer 42

Archaea share traits with both but are genetically distinct, often thriving in extreme environments.

Question 43

# 3.1 Classification What is a key biochemical similarity between echinoderms and vertebrates?

Answer 43

Both share similar ATP synthesis processes and embryological development, indicating a close evolutionary relationship.

Question 44

# 3.1 Classification What are two main blood pigments used by animals?

Answer 44

Hemoglobin (vertebrates) and hemocyanin (molluscs and arthropods).

Question 45

# 3.1 Classification Describe a detailed process of gel electrophoresis

Answer 45

1. DNA is cut into fragments using restriction enzymes. 1. Fragments are placed into gel wells with a buffer solution. 1. An electric current is applied; DNA fragments move based on size. 1. Smaller fragments move faster/farther than larger ones. 1. Bands are visualized with a dye (e.g., ethidium bromide under UV light).

Question 46

# 3.1 Classification Describe how archea was introduced to the 3 domain system

Answer 46

* Early classification split organisms into two groups: * Eukaryotes (cells with a nucleus). * Prokaryotes (cells without a nucleus, e.g., bacteria). * The discovery of Archaea in the 1970s suggested a third domain: * Archaea share traits with both bacteria and eukaryotes. * Some believe mitochondria arose from bacterial endosymbionts.

Question 47

# 3.1 Classification What role do scientific journals play in the scientific process?

Answer 47

Scientific journals, along with the peer review process and scientific conferences, play a crucial role in validating new evidence that supports the accepted scientific theory of evolution.

Question 48

# 3.1 Classification What are the five kingdoms in the five-kingdom classification system?

Answer 48

Monera (prokaryotes) Protista (eukaryotic single-celled organisms) Fungi (heterotrophic eukaryotes) Plantae (autotrophic eukaryotes) Animalia (heterotrophic multicellular eukaryotes).

Question 49

# 3.1 Classification What are extremophiles?

Answer 49

Bacteria that live in extreme environments, such as high heat, salinity, or acidity.

Question 50

# 3.1 Classification What are heterotrophs and autotrophs?

Answer 50

Organisms that cannot make their own food and must consume other organisms.(heterotroph) Organisms that make their own food through photosynthesis or chemosynthesis.(autotroph)

Question 51

# 3.1 Classification What are key features of the Protista kingdom?

Answer 51

Protista-Includes single-celled eukaryotic organisms which mostly reproduce asexually.

Question 52

# 3.1 Classification What are the main characteristics of fungi?

Answer 52

Includes both unicellular and multicellular heterotrophic eukaryotes that reproduce sexually or asexually.

Question 53

# 3.1 Classification Define an endosymbiont.

Answer 53

An organism that lives inside the cells or body of another organism.

Question 54

# 3.2 Natural selection Define natural selection in the context of evolution.

Answer 54

Natural selection is the process by which evolution occurs through variation among organisms, leading to adaptations that enhance survival and reproduction.

Question 55

# 3.2 Natural selection How do organisms occupy niches?

Answer 55

Organisms occupy niches based on their physiological, behavioral, and anatomical adaptations that allow them to thrive in specific environments. ALTERNATE defintion: The process by which organisms with traits better suited to their environment are more likely to survive and reproduce.

Question 56

# 3.2 Natural selection What is the significance of reproductive isolation in speciation?

Answer 56

Reproductive isolation can lead to allopatric and sympatric speciation by preventing different populations from interbreeding, allowing them to evolve into distinct species.

Question 57

# 3.2 Natural selection Describe the evolutionary race between pathogens and medicines.

Answer 57

There is an evolutionary race between pathogens and the development of medicines, as pathogens evolve to resist treatments while scientists work to create effective medicines.

Question 58

# 3.2 Natural selection What are the key ideas behind Darwin's theory of evolution?

Answer 58

1. Living organisms reproduce sexually, showing genetic variation. 1. Organisms produce excess offspring, but not all survive due to competition. 1. Favorable traits give a survival and reproductive advantage. 1. These traits are passed on, increasing their frequency in future generations. 1. Traits reducing survival chances decrease in frequency.

Question 59

# 3.2 Natural selection What is the modern understanding of evolution?

Answer 59

Evolution occurs due to differential survival and reproduction of organisms with different genotypes in a specific environment. Natural selection favors traits that improve survival or reproduction.

Question 60

# 3.2 Natural selection What are the three types of adaptations?

Answer 60

Physiological Adaptations: Internal body functions aiding survival (e.g., mammalian diving response). Behavioral Adaptations: Instinctive or learned behaviors increasing survival (e.g., penguins huddling for warmth). Anatomical Adaptations: Physical structures enhancing survival (e.g., sticky hairs on sundew plants trapping insects).

Question 61

# 3.2 Natural selection How do behavioral adaptations improve survival?

Answer 61

By enabling organisms to manage environmental challenges, such as thermoregulation (e.g., lizards basking in the sun) or social behaviors (e.g., penguins huddling).

Question 62

# 3.2 Natural selectionz What is a successful species?

Answer 62

A species well-adapted to its niche, with traits that improve survival and reproduction, passed on to the next generation.

Question 63

# 3.2 Natural selection What processes can lead to genetic variation in populations?

Answer 63

Mutation, sexual reproduction, inbreeding, and hybridization.

Question 64

# 3.2 Natural selection What is the difference between natural selection and evolution?

Answer 64

Natural selection is the process of survival and reproduction of the fittest, while evolution is the long-term result of this process, leading to changes in populations.

Question 65

# 3.2 Natural selection What is Neo-Darwinism?

Answer 65

An updated model of evolution that incorporates genetic and molecular biology advancements, highlighting the role of DNA in variation.

Question 66

# 3.2 Natural selection Why are niches important in evolution?

Answer 66

Niches define how species interact with their environment and other organisms, driving adaptations to improve survival in specific roles or habitats.

Question 67

# 3.2 Natural selection Define directional selection.

Answer 67

Directional selection is a type of natural selection that favors one extreme phenotype, leading to a shift in a population's traits over time in response to environmental pressures.

Question 68

# 3.2 Natural selection How does directional selection affect the gene pool?

Answer 68

It increases the frequency of alleles that provide a survival or reproductive advantage within a population.

Question 69

# 3.2 Natural selection Define reproductive success.

Answer 69

Reproductive success is the ability of an organism to pass its genes to the next generation by producing offspring that survive and reproduce.

Question 70

# 3.2 Natural selection Why do some traits enhance reproductive success but not survival?

Answer 70

Traits like long tails in widow birds or bee-like flowers in orchids are adaptations that make organisms more attractive to mates or pollinators, boosting reproduction without necessarily improving survival.

Question 71

# 3.2 Natural selection How did bacteria develop resistance to penicillin, and therefore How does natural selection lead to antibiotic resistance?

Answer 71

Random mutations allowed some bacteria to produce enzymes that deactivated penicillin. These resistant bacteria survived and reproduced. Antibiotics kill non-resistant bacteria, allowing resistant strains to survive, reproduce, and dominate bacterial populations.

Question 72

# 3.2 Natural selection What are some factors that contribute to antibiotic resistance?

Answer 72

Overuse of antibiotics Incorrect use of antibiotics (e.g., not completing the full course) Widespread use of antibiotics in agriculture Poor hygiene practices

Question 73

# 3.2 Natural selection What are the consequences of antibiotic resistance?

Answer 73

More difficult to treat infections, leading to increased illness and death Development of new antibiotics becomes more challenging and expensive

Question 74

# 3.2 Natural selection What is speciation?

Answer 74

The formation of new species due to reproductive isolation.

Question 75

# 3.2 Natural selection What is the key factor in speciation?

Answer 75

Reproductive isolation, which prevents gene flow between populations.

Question 76

# 3.2 Natural selection What is allopatric speciation?

Answer 76

Speciation that occurs due to geographical separation of populations.

Question 77

# 3.2 Natural selection Give an example of allopatric speciation.

Answer 77

The evolution of Madagascar’s endemic species due to geographic isolation.

Question 78

# 3.2 Natural selection What is sympatric speciation?

Answer 78

Speciation that occurs within the same location due to reproductive isolation.

Question 79

# 3.2 Natural selection What is adaptive radiation?

Answer 79

When one species rapidly evolves into multiple species to fill different ecological niches.

Question 80

# 3.2 Natural selection Name five isolating mechanisms in speciation.

Answer 80

Geographical, ecological, seasonal, behavioural, and mechanical isolation.

Question 81

# 3.2 Natural selection What is hybridisation in speciation?

Answer 81

When two closely related species interbreed, sometimes forming fertile or sterile offspring.

Question 82

# 3.2 Natural selection Describe the five isolation mechanisms?

Answer 82

1. Geographical isolation: Physical barriers (e.g., rivers, mountains). 1. Ecological isolation: Species inhabit different parts of the same region. 1. Seasonal isolation: Differences in mating seasons or flowering times. 1. Behavioural isolation: Differences in courtship or mating patterns. 1. Mechanical isolation: Physical incompatibility in reproductive structures.

Question 83

# 3.3 Biodiversity What formula can be used to calculate the level of biodiversity within a habitat?

Answer 83

D = N(N-1) / Σn(n-1) Where: D = Index of diversity N = Total number of organisms of all species n = Total number of organisms of each1 individual species

Question 84

# 3.3 Biodiversity Why is maintaining biodiversity important?

Answer 84

For ethical and economic reasons, including ecosystem services.

Question 85

# 3.3 Biodiversity How is genetic biodiversity assessed?

Answer 85

By looking at the variety of alleles in the gene pool of a population.

Question 86

# 3.3 Biodiversity What are the principles of in-situ conservation?

Answer 86

In-situ conservation involves protecting habitats to maintain biodiversity in their natural environments.

Question 87

# 3.3 Biodiversity What are the principles of ex-situ conservation?

Answer 87

Ex-situ conservation involves measures like zoos and seed banks to preserve biodiversity outside of natural habitats.

Question 88

# 3.3 Biodiversity What are the issues surrounding in-situ and ex-situ conservation?

Answer 88

Challenges include ethical considerations, resource allocation, and ensuring long-term effectiveness for biodiversity maintenance.

Question 89

# 3.3 Biodiversity

Question 90

# 3.3 Biodiversity

Question 91

# 3.3 Biodiversity

Question 92

# 3.3 Biodiversity

Question 93

# 3.3 Biodiversity What is endemism?

Answer 93

Endemism refers to species that are unique to a specific geographic location and found nowhere else, often in biodiversity hotspots.

Question 94

# 3.3 Biodiversity Why are biodiversity hotspots important but vulnerable?

Answer 94

Biodiversity hotspots have high species richness and endemism but are often at risk of damage due to habitat loss, climate change, and human activity.

Question 95

# 3.3 Biodiversity What does species abundance refer to, and why is it important in biodiversity?

Answer 95

Species abundance is the relative proportion of different species in an area. Even distribution of species increases biodiversity, compared to dominance by a few species.

Question 96

# 3.3 Biodiversity How does the diversity index reflect biodiversity in an area?

Answer 96

A higher diversity index value indicates a greater variety of organisms and a healthier, more balanced ecosystem.

Question 97

# 3.3 Biodiversity What factors contribute to high biodiversity in an area?

Answer 97

High biodiversity is typically seen in: * Very stable ecosystems, which allow complex relationships between species. * Areas with high productivity (e.g., high photosynthesis rates), supporting more niches. * Areas where organisms grow and reproduce rapidly, increasing mutations and adaptations.

Question 98

# 3.3 Biodiversity How do extreme environmental conditions affect biodiversity?

Answer 98

Extreme environments tend to have low biodiversity because: * They are unstable and susceptible to rapid changes. * A single event (e.g., flood or disease) can devastate populations. * Few organisms are adapted to survive in such conditions.

Question 99

# 3.3 Biodiversity Why is biodiversity not constant throughout the year?

Answer 99

Biodiversity can change due to: Seasonal migration of species. Temperature and environmental shifts affecting species presence. Different habitats being active at varying times (e.g., wetlands in winter vs. summer).

Question 100

# 3.3 Biodiversity What is a biodiversity hotspot, and why is it significant?

Answer 100

A biodiversity hotspot is an area with exceptionally high species richness and endemism. These areas are highly vulnerable to damage and loss, making them critical for conservation.

Question 101

# 3.3 Biodiversity How does species richness differ from relative species abundance?

Answer 101

Species richness refers to the number of different species in an area. Relative species abundance is the proportion of individuals of each species relative to the total population.

Question 102

# 3.3 Biodiversity How does biodiversity loss occur, and what are its implications?

Answer 102

Biodiversity loss can result from: Natural events (e.g., volcanoes, flooding). Human activities (e.g., habitat destruction, pollution). Implications: Loss of ecosystem stability and services. Decrease in the gene pool and extinction of species.

Question 103

# 3.3 Biodiversity What are mutations, and how can they affect an organism?

Answer 103

Mutations are changes in DNA structure, ranging from small (e.g., a single base pair) to large (e.g., loss or duplication of a chromosome). Their effects vary: * No effect on phenotype (neutral). * Severe or lethal effects. * Advantageous effects that improve survival.

Question 104

# 3.3 Biodiversity How do mutations impact the gene pool of a population?

Answer 104

Mutations increase the gene pool by introducing new alleles, which enhances genetic diversity and improves the population's ability to adapt to environmental changes.

Question 105

# 3.3 Biodiversity What is allele frequency, and how is it affected by mutations?

Answer 105

Allele frequency is the relative proportion of a specific allele in a population. * Advantageous mutations increase in frequency due to natural selection. * Disadvantageous mutations are often removed unless they provide some benefit in changing conditions.

Question 106

# 3.3 Biodiversity How do natural selection and environmental shifts influence allele frequency?

Answer 106

Natural selection drives changes in allele frequency, favoring beneficial traits and potentially leading to new species. Environmental changes can make previously disadvantageous alleles beneficial, increasing their frequency.

Question 107

# 3.3 Biodiversity What are neutral mutations, and how common are they?

Answer 107

Neutral mutations neither help nor harm the organism and do not affect the phenotype. They are common, with an average baby inheriting around 100 new neutral mutations.

Question 108

# 3.3 Biodiversity What are the different types of ex-situ conservation?

Answer 108

Captive breeding programmes: Increase population & genetic diversity using techniques like IVF, stud books, and gamete exchange. Reintroduction programmes: Release captive-bred animals to restore habitats. Seed banks: Store seeds to conserve genetic diversity and prevent extinction. Advantages: Conserves many species, takes less space, and is cheaper than storing plants. Seeds stored in cool, dry conditions & periodically tested for viability.

Question 109

# 3.3 Biodiversity What are the different types of in-situ conservation?

Answer 109

Education programmes: Teach importance of biodiversity and risks like illegal wildlife trade. Protected areas: National Parks & Sites of Scientific Interest conserve habitats and biodiversity.