A-Level Biology (OCR) > 4: Biodiversity & Classification > Flashcards

4: Biodiversity & Classification Flashcards

Measure biodiversity and classify organisms using phylogenetic systems. (32 cards)

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1
Q

What defines whether two organisms belong to the same species?

A

The ability to produce fertile offspring.

Members of the same species must be capable of breeding and producing fertile offspring.

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2
Q

Why is courtship behaviour important before mating in many organisms?

A

Species recognition

Courtship behaviours help individuals identify members of their own species and avoid unsuccessful mating attempts.

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3
Q

True or False:

Courtship behaviour has no role in reproductive success as long as two organisms can physically mate.

A

False

Courtship is often required to trigger mating behaviour and ensure recognition of the correct species.

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4
Q

What is the term for a biological classification group within a hierarchy such as genus or family?

A

Taxon

Taxon (plural: taxa) refers to any classification grouping used in biological taxonomy.

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5
Q

What type of classification system groups organisms according to their evolutionary relationships?

A

Phylogenetic classification

This system reflects evolutionary ancestry and genetic relatedness rather than just physical similarity.

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6
Q

True or False:

In a hierarchical classification system, taxa can overlap between groups.

A

False

Each organism belongs to only one group at each taxonomic level.

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7
Q

Fill in the blank:

In classification hierarchies, smaller groups are placed within ______ groups.

A

larger

Taxonomic hierarchies nest smaller taxa within broader categories.

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8
Q

What is the smallest taxonomic rank in the standard biological hierarchy?

A

Species

Species represents the most specific classification level.

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9
Q

What taxonomic rank groups together closely related species?

A

Genus

A genus contains species that share close evolutionary relationships.

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10
Q

Fill in the blank:

The scientific name of an organism consists of its genus and ______.

A

species

These two names together form the binomial scientific name.

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11
Q

What is the universal two-part naming system used to identify species?

A

Binomial nomenclature

Introduced by Linnaeus; ensures each species has a globally recognised name.

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12
Q

In the scientific name Homo sapiens, what taxonomic level does Homo represent?

A

Genus

The first word of a binomial name identifies the genus.

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13
Q

In the scientific name Homo sapiens, what taxonomic level does sapiens represent?

A

Species

The second word distinguishes the species within the genus.

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14
Q

True or False:

Species names are universally standardised so scientists worldwide refer to the same organism.

A

True

Binomial nomenclature prevents confusion caused by common names.

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15
Q

What is the highest taxonomic rank in the hierarchy: domain, kingdom, phylum, class, order, family, genus, species?

A

Domain

Domain sits above kingdom in modern classification hierarchies.

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16
Q

Fill in the blank:

The taxonomic hierarchy from broad to specific includes domain, kingdom, phylum, class, order, ______, genus and species.

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A

family

Family groups together related genera.

17
Q

Which scientific field studies immune system proteins that can be compared between species to determine relatedness?

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A

Immunology

Similarities in antibodies and proteins can indicate evolutionary relationships.

18
Q

What modern biological technique compares DNA sequences to determine evolutionary relationships between organisms?

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A

Genome sequencing

DNA comparison provides strong evidence of common ancestry.

19
Q

True or False:

Genome sequencing has helped refine evolutionary relationships used in classification.

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A

True

Molecular evidence can confirm or revise relationships previously inferred from morphology.

20
Q

What overarching goal does a phylogenetic classification system aim to reflect when grouping organisms?

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A

Evolutionary origins

Organisms are grouped according to common ancestry and divergence over time.

21
Q

What does biodiversity describe within a community?

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A

Variety of species

Biodiversity refers to the range and variety of different species present in a habitat or community.

22
Q

A woodland contains 25 different species of plant. Which measure of biodiversity does this represent?

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A

Species richness

Species richness counts how many different species are present, regardless of population size.

23
Q

Why might two communities with the same species richness have different biodiversity values?

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A

Differences in relative abundance.

Biodiversity also depends on how evenly individuals are distributed among species.

24
Q

True or False:

A community with many species but dominated by one species will have a high diversity index.

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A

False

If one species dominates numerically, the diversity index decreases because individuals are unevenly distributed.

25
What does the value **N** represent in the **diversity index formula**?
Total number of organisms ## Footnote N is the total number of individuals across all species sampled in the community.
26
In the **diversity index formula**, what does **n** represent?
Number of individuals in a species ## Footnote Each species has its own n value representing how many individuals belong to that species.
27
# Fill in the blank: The **diversity index** is calculated using the formula d = N(N−1) divided by \_\_\_\_\_\_.
Σn(n−1) ## Footnote The denominator is the sum of n(n−1) calculated for each species in the sample.
28
What does a **higher index of diversity value** indicate about a **community**?
Greater biodiversity ## Footnote Higher values indicate many species and a more even distribution of individuals.
29
# True or False: If **all species** in a community have **similar population sizes**, the diversity index tends to be higher.
True ## Footnote Even distribution of individuals across species increases the diversity index.
30
Biodiversity can be measured at **different scales**. What **term** describes biodiversity measured across the **whole planet**?
Global biodiversity ## Footnote Biodiversity can range from small local habitats to the entire Earth.
31
How do many **intensive farming techniques** typically affect **biodiversity**?
Reduce biodiversity ## Footnote Monocultures, pesticide use, and habitat removal reduce species variety.
32
What key **environmental decision** must often be balanced when managing **farmland biodiversity**?
Conservation vs food production ## Footnote Agricultural productivity must often be balanced with maintaining habitats and species diversity.
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