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SNAB A Level Biology > Topic 4: Biodiversity and Natural Resources > Flashcards

Topic 4: Biodiversity and Natural Resources Flashcards

1
Q

what is a species

A

a group of organisms with similar morphology, physiology and behaviour, that can interbreed to produce fertile offspring

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2
Q

what is a population

A

one species in a specific area

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3
Q

what is a community

A

all the different populations within a habitat

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4
Q

what is an ecological niche

A

the way an organism exploits it’s enviroment

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5
Q

what does a niche include?

A

interactions with biotic factors
interactions with abiotic factors

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6
Q

what will happen if 2 species try to occupy the same niche

A

they will compete with each other and one species will be more successful and outcompete the other

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7
Q

what are the 3 types of adaptations

A

behavioural - e.g playing dead
physiological - internal workings e.g hibernation
structural - e.g thorns

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8
Q

what is evolution

A

a change in inherited characteristics within a population over time due to natural selection

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9
Q

describe how natural selection occurs

A
  1. a pop has a mutation that provides an advantageous characteristic
  2. a selection pressure occurs in the environment
  3. survival of the fittest - advantageous allele
    4.organisms w/ the allele are more likely to survive, reproduce … producing offspring
  4. the offspring are more likely to have the allele, and over time it becomes more common in the population
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10
Q

what is speciation

A

the formation of a new species

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11
Q

what must happen for speciation to occur

A

reproductive or geographical isolation

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12
Q

how does geographical isolation lead to speciation?

A
  1. a geographical barrier separates and prevents a population from breeding with each other
  2. over time the 2 groups become less like each other as they respond to different selection pressures and random mutations accumulate
  3. eventually, 2 groups cannot interbreed to produce fertile offspring
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13
Q

how does reproductive isolation lead to speciation?

A
  1. occurs when changes in the alleles and phenotypes of some individuals prevent them from successfully breeding with others

e.g seasonal changes like mating/flowering season

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14
Q

what is a gene pool

A

all the alleles of all the genes present in a population

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15
Q

what is the benefit of having a bigger gene pool

A

greater genetic diversity - more likely to possess alleles that allow them to survive

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16
Q

what is the Hardy Weinburg equation used for?

A

to see if there has been a change in allele frequency over time

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17
Q

what is the Hardy Weinburg equation

A

q^2 + 2pq + p^2 =1
p + q = 1

p= frequency of dominant allele
q= frequency of recessive allele

2pq= the chance of an individual being heterozygous
q^2 = the chance of homozygous recessive
p^2 = chance of homozygous dominant

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18
Q

what are the assumptions of the Hardy Weinburg?

A
  • random mating
  • infinitely large population
  • no migration, mutation or natural selection
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19
Q

what factors determine the ability of a population to adapt to new conditions?

A
  1. strength of selection pressure
  2. size of gene pool
  3. reproductive rate of organism
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20
Q

what is biodiversity - 2 definitions

A

variety of species in an ecosystem, community , habitat
variety of alleles in a gene pool

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21
Q

what are the 3 levels to assess biodiversity?

A

∞ number and range of diff ecosystems/habitats
∞ number of species and their relative abundance
∞ genetic variation within a species

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22
Q

what is endemism

A

when a species is only found in one geographical location

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23
Q

what is species richness

A

the number of species present in a given habitat

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24
Q

what is species evenness

A

relative abundances of different species within a community

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25
how do you measure heterozygosity index?
number of heterozygotes H = ------------------------------------------ number of individuals in a population
26
what is the index of diverity
measurement that describes the relationship between the no. of species present, and how each species contributes to the total number of organisms that are present in that community
27
formula for index of diversity
N(N-1) d = -------------------- ∑n(n-1) n = total no. of organisms for a single species in the community N = total no. of organisms in the community
28
What is the order of classification levels? D- KPCOFGS
Domain Kingdom Phylum Class Order Family Genus Species
29
What are the 3 domains of life - and what are they based on?
Bacteria, Eukaryota, Archaea based on new information obtained from molecular phylogeny - analysis of RNA genes
30
How are organisms classified?
based on molecular phylogeny - evolutionary history relies on similarities or differences of molecules within organisms eg, DNA, RNA, proteins
31
What are the 5 kingdoms of classification?
Prokaryotae Protictista Fungi Plantae Animalia
32
5 key features of Kingdom Prokaryotae
* single celled * peptidoglycan cell wall * no organelles or nucleus * very tiny * absorb nutrients via cell wall or photosynthesis
33
5 features of Kingdom Protoctista
* eukaryotes * single-celled, move by flagella or cilia * most forms dont have cell wall * have organelles + nucleus, some have chloroplasts * nutrients acquired via photosynthesis or ingestion
34
5 features of Kingdom Fungi
* eukaryotic * multi or uni cellular * chitin cell wall * have organelles + nucleus , no chloroplasts * nutrients absorbed via absorption
35
5 features of kingdom plantae
* eukaryotic * multicellular * usually dont translocate * have organelles + nucleus + chloroplasts + cellulose cell wall * nutrients acquired via photosynthesis
36
5 features of kingdom animalia
* eukaryotic * multicellular * move with cilia, flagella, or muscular organs * organelles + nucleus, no chloroplast or cell walls * nutrients acquired via ingestion
37
structure and function of plant cell wall
made of mainly cellulose function - support plant cells
38
what is the function of the middle lamella and where is it found
it is the outermost layer of the cell and acts as an adhesive, sticking adjacent plant cells together
39
what are plasmodesmata and what is their function
channels in cell walls that link adjacent cells together for transport of substances and communication between cells
40
what are pits and what is their function
regions where the cell wall is very thin, and it allows for transport of substances between cells
41
what is an amyloplast and what is its function
small organelle enclosed by a membrane, it contains starch granules for starch storage
42
what is the function of the vacuole and tonoplast?
vacuole contains cell sap (water, enzymes, minerals, water) it keeps the cells turgid and is involved in the breakdown and isolation of unwanted chemicals the tonoplast is the surrounding membrane of the vacuole and it controls what enters and what leaves
43
in which two places inside the chloroplast does photosynthesis occur
grana and stroma
44
what is the function of xylem vessels?
transport water and mineral ions and to provide support
45
what is the structure of the xylem vessels
long, thin structures formed by cells with hollow lumen and no end walls thickened with lignin for support water and mineral ions move in and out through pits in the walls where there's no lignin the tubes are found together in bundles
46
what is the function of sclerenchyma fibres
to provide support
47
what is the structure of sclerenchyma fibres
made of dead, hollow, long cells but these cells do have end walls cell walls thickened in lignin they have more cellulose
48
function of phloem
transports sugars and mineral ions from where they are made to where they are needed - translocation
49
what is the structure of phloem cells
made out of tubes of cells made from 2 types of cells - sieve tube elements and companion cells sieve tube elements have sieve plates at the end walls which contain holes to allow solutes to pass through - they have no nucleus, thin cytoplasm, few organelles 1 companion cell for every sieve tube element - they carry out living function for both themselves and their sieve cells
50
what is the chemical structure of starch and how does it relate to its function
starch made from amylose + amylopectin = two alpha glucose chains amylose = long unbranched chain - makes it compact, so good for storage amylopectin = branched chain - side chains allow for quicker hydrolysis of glucose starch is insoluble, so it wont cause water to enter cells by osmosis, preventing them from swelling
51
what is the chemical structure of cellulose and how does it relate to its structure
long, unbranched chains of beta-glucose, joined by 1,4 straight glycosidic bonds H bonds join between 50-80 cellulose chains together forming microfibrils they are strong so provide structural support
52
what are the 2 main reasons as to why plant fibres are so strong
* net like arrangement of cellulose microfibrils and their strength * secondary cell wall - between cell wall and membrane- contains more lignin and is thicker.
53
how do you measure the tensile strength of plant fibres
attach the fibre to a clamp stand and hang a weight from the other end keep adding weights until the fibre breaks - record the mass needed to break it repeat with diff samples of the same fibres + same length. Calculate the mean of results * safety - wear goggles + be careful w the masses
54
what is sustainability
using the resources to meet the needs of the present without sacrificing the needs of future generations
55
what are renewable resources
resources that can be used indefinitely without running out
56
how can using plant fibres contribute to sustainability
1. can substitute plastic 2. biodegradable 3. plants are easier to grow and process than oil, and they are cheaper
57
how can using starch contribute to sustainability
- can make bioplastics - can make biofuels - substitutes the use of fossil fuels such as oil and therefore increases sustainability
58
why do plants need water
- photosynthesis - transporting minerals - structural rigidity - regulate temperature
59
why do plants need magnesium ions
production of chlorophyll
60
why do plants need nitrate ions
production of DNA, proteins and chlorophyll
61
why do plants need calcium ions
important in cell walls - they are required for plant growth

SNAB A Level Biology (5 decks)

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