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Biology 🌿 > classification and biodiversity > Flashcards

classification and biodiversity Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

phylogeny

A

study of evolutionary history of a group of organisms

all organisms evolved from shared common ancestors
tree shows relationships

first branch shows common ancestor of all family members
closely related species diverged most recently

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2
Q

what is taxonomy?

A

study of classification
naming organisms and organising them into groups
takes into account phylogeny (evolutionary relationships)

easier to identify and study them

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3
Q

what is meant by a hierarchy?

A

larger groups contain smaller groups
with no overlap

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4
Q

how is taxonomy done?

A

levels of groups (taxon) used to classify organisms
arranged into hierarchy with largest groups at top
- only belong to one group at each level, no overlap

highest = domain - eukarya, bacteria and archaea

as move down
- more groups but fewer organisms in each
- more closely related

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5
Q

8 taxa

A

domain
kingdom
phylum
class
order
family
genus
species

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6
Q

binomial naming system (+ use)

A

genus name (capital letter)
species name (lower case)

written in italics or underlined

all organisms given one internationally accepted scientific name in latin
- avoid confusion of common names

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7
Q

what is courtship behaviour?

A

carried out by organisms to attract a mate of the same species
results in reproduction

species specific - only members of same species will do and respond to that behaviour
- more closely related = more similar

means it can be used to classify organisms

allows species recognition and prevent interbreeding
= reproduction more successful = fertile offspring

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8
Q

technologies used for classifying evolutionary relationships

A

used to be done by observable characteristics now based of DNA sequences

  • genome sequencing
  • immunology
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9
Q

how can genome sequencing be used to classify organisms

A

base sequences on DNA
base sequence of mRNA
amino acid sequence

more similar = more closely related

those less closely related have had time to introduce mutations into DNA, making it less similar

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10
Q

how can immunology be used to classify evolutionary relationships?

A

immunological comparisons
- similar proteins = similar shape so bind to same antibodies
- antibodies for a human protein will bind more to a closely related organisms proteins as they have more similar shapes

more antigen antibodies complexes (more binding) = more closely related

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11
Q

how can proteins be analysed to determine genetic relationships?

A

proteins made from amino acid sequence
sequence determined by DNA base sequence
so more similar proteins = more similar DNA, so more closely related

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12
Q

what is biodiversity?

A

variety of living organisms in an area

high = lots of different species

measured by
- species richness (doesn’t consider population sizes)
- index of diversity

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13
Q

what is a community?

A

all the populations of different species in a habitat

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14
Q

difference between species richness and index of diversity

A

both show the number of different species in a community

index also shows the population sizes of each species

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15
Q

what is species richness?

A

measure of the number of different species in a community

take random sample
count number of different species

simple measure of biodiversity
- doesn’t take into account number of individuals in each species

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16
Q

index of diversity

A

shows relationship between number of species in a community and the number of individuals in each species

N = total number of organisms of all species
n = total number of organisms of each species

17
Q

why are ecosystem with a high index of diversity more stable?

A

have a higher number of species in a community, and are equally sized species populations

more resilient to environmental changes

18
Q

ways agriculture is made more productive

A

removing hedgerows = bigger fields
monoculture = cans specialise
fertilisers and pesticides increase yields

19
Q

how does agriculture reduce biodiversity? (5)

A

woodland clearance
- increase area of farmland
- reduces number of trees
- removes habitats so less species

hedgerow removal
- increase area by making small fields into larger ones
- removes plants
- removes habitats so reduces species

pesticides
- directly kills pests
- species that feed on pests loose food source, die

herbicides
- reduces plant species (weeds)
- and species that feed on them

monoculture
- reduce variety of species
- supports fewer organisms (less food source)

20
Q

balancing agriculture and conservation

A

conservation aims to protect biodiversity

eg legal protection to endangered species
protected areas

21
Q

ways of measuring genetic diversity

A
  • frequency of observable characteristics
  • base sequence of DNA
  • base sequence of mRNA (amino acids)
  • proteins coded for by DNA and mRNA
22
Q

what is genetic diversity?

A

number of different alleles of genes in a population

increased by:
- mutations
- gene flow (introduction of alleles by migration and breeding)

23
Q

what can affect allele frequency in a population?

A

natural selection
founder effect
genetic bottleneck
genetic drift (chance)

24
Q

genetic bottleneck

A

event that causes big reduction in a population
reduces number of alleles in gene pool
so reduces genetic diversity

survivors reproduce and large population created from few individuals
with reduced genetic diversity (fewer alleles)
(founder effect)

25
Q

founder effect

A

when a few organisms from a population start a new colony
- only a small number of different alleles in the initial gene pool

frequency of alleles change
may be more but less variety of different alleles
- can increase genetic disease if with a mutated allele

occur due to:
- migration (leading to geographical isolation)
- genetic bottleneck

26
Q

natural selection

A

changes allele frequency overtime
increases advantageous alleles in a population
= organisms more adapted

  • individuals with beneficial allele (better adapted to selection pressures) more likely to survive and reproduce
  • genes and beneficial allele passed on
  • greater proportion of next generation inherit allele
  • they are also more likely to survive and reproduce

frequency of beneficial allele increases from generation to generation

(beneficial allele from a random mutation, if harmful, dies out as organisms die)

27
Q

adaptations due to natural selection

A

behavioural - way an organism acts
eg basking in sun to keep warm

psychological - processes within an organism
eg hibernation

anatomical - structural features of an organism
eg camouflage

leads to evolution as organisms become better adapted to their environment
have increased chance of survival

28
Q

ways of studying genetic diversity

A

observable characteristics
- less reliable, only infer relationships

base sequence of DNA
- abstract from nucleus

base sequence of mRNA
- easier as abstracted from cytoplasm
- create complementary strand (DNA sequence)

amino acid sequence
- easier to obtain proteins than DNA
- proteins evolve much slower, more likely to be similar to ancestors

more similar = more closely related

29
Q

directional selection

A

individuals with alleles for extreme characteristics more likely to survive and reproduce

could be in response to environmental changes

eg antibiotic resistance
those with resistance allele survive, passed on, increased number with resistance allele

30
Q

stabilising selection

A

individuals with characteristics towards middle of range more likely to survive and reproduce

occurs when environment isn’t changing - reduces range of phenotypes

eg human birth weights
those with mid weights more likely to survive, range smaller

31
Q

why is there variation between and within species?

A

variation between species as they have different genes

variation within species as they have different alleles
or face different selection pressures in the environment

32
Q

random vs systematic sampling

A

random
- points chosen by chance (eg grid and using random number generator)
- avoids bias

systematic
- chose areas to sample
- bias, could chose areas with less or more species
- creates unrepresentative sample

33
Q

calculating % cover

A

count number of squares in quadrat with species
each square = 1%

34
Q

calculating abundance of species

A

count number of quadrats with species
number with species / number of quadrats
eg 3/10 = 30%

35
Q

what is a gene pool

A

complete range of allele in a population

Biology 🌿 (23 decks)

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