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Edexcel Biology
Paper 1
Biodiversity & nat. resources
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Created by
Connor McKeown
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Cards (101)
What is biodiversity?
The variety of living
organisms
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How is biodiversity currently being threatened?
By human activity such as
deforestation
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What are the two main measures of biodiversity?
Species richness
: number of
different
species
Genetic diversity
:
genetic
variation in a species
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What does species richness refer to?
The number of
different
species in a habitat
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What is genetic diversity?
A measure of
genetic variation
in a
species
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How is biodiversity within a species measured?
By calculating the
heterozygosity index
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What is the formula for the heterozygosity index (H)?
H = number of
heterozygotes
/ number of
individuals
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What is the index of diversity (D) used for?
To measure and compare
biodiversity
between
habitats
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What does endemism refer to?
A
species
unique
to a specific location
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What is an ecological niche?
The role of a
species
within its community
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How do species compete within the same niche?
Better-
adapted
species outcompete others
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What is the basis of natural selection?
Better
adapted
species
survive
and reproduce
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What are anatomical adaptations?
Physical adaptations of
organisms
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What are behavioral adaptations?
Changes in behavior that improve
survival
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What is a physiological adaptation?
Processes that increase
survival chances
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What is the process of natural selection?
Fitter individuals
survive
and pass on
alleles
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What is evolution in terms of allele frequency?
Change in allele frequency
over time
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What are the steps of evolution via natural selection?
Variety of
phenotypes
exists due to
mutation
Environmental change alters
selection pressure
Some individuals have advantageous
alleles
Advantageous alleles are passed to
offspring
Allele frequency
in population changes over time
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What is the Hardy-Weinberg Equation used for?
Estimating
allele frequency
in a population
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What does p represent in the Hardy-Weinberg Equation?
The frequency of the
dominant allele
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What does q represent in the Hardy-Weinberg Equation?
The frequency of the
recessive allele
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What does p^2 represent in the Hardy-Weinberg Equation?
Frequency of
homozygous dominant
individuals
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What does 2pq represent in the Hardy-Weinberg Equation?
Frequency of
heterozygous
individuals
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What does q^2 represent in the Hardy-Weinberg Equation?
Frequency of
homozygous recessive
individuals
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What is the equation for a population in genetic equilibrium?
p + q =
1.0
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What is the expanded Hardy-Weinberg Equation?
(p + q)^2 = 1 hence
p^2
+
2pq
+ q^2 = 1
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What are the conditions for the Hardy-Weinberg Equation?
No
mutations
Random mating
Large population
Isolated population
No
selection pressure
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What happens when two populations become reproductively isolated?
New species form due to
genetic differences
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What is speciation?
The formation of new
species
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What is allopatric speciation?
Speciation due to
geographical
isolation
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What is sympatric speciation?
Speciation
within
the
same
area
by
other
means
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What is classification in biology?
Organizing life based on relationships
Using differences and similarities in
phenotypes
and
genotypes
Five-kingdom model
: animals, plants, fungi, protists, monera
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What is the binomial system of naming species?
Genus
name followed by
species
name
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What is molecular phylogeny?
Analysis
of
molecular
differences
for
evolutionary
relationships
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What did molecular phylogeny lead to?
New
taxonomic
groupings in classification
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What are the three domains in the Three-Domain model?
Bacteria
,
Archaea
,
Eukaryota
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How does the scientific community evaluate data?
Findings published in
scientific journals
Presented at scientific
conferences
Evidence studied through
peer review
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What type of cells are plant cells?
Eukaryotic cells
with a
nucleus
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What structures are unique to plant cells?
Cell wall made of
cellulose
Plasmodesmata
for substance transport
Chloroplasts
for photosynthesis
Amyloplasts
for starch storage
Vacuole
for strength and support
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What is the function of the cell wall in plant cells?
Provides
structure
and
support
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