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Biology A level revision > 18. Classification, Biodiversity & Conservation > Flashcards

18. Classification, Biodiversity & Conservation Flashcards

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1
Q

Define Species

A

A group of organisms with similar morphological and physiological features that able to breed together and produce fertile offspring

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2
Q

What is the Morphological species concept?

A

they are a group organisms that share physical features that distinguish them from other species

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3
Q

What does Morphological mean?

A

physical features

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4
Q

What is the Ecological species concept?

A

When there is a population of similar organisms living in the same area at the same time, they can be described as ecological species

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5
Q

Which system is used to name species?

A

the Binomial system

first part of name is - genus that the species belongs to - group of very similar organism

second part of name is specific and unique to a single group of organisms that are identified as species

The binomial name is always italicized in writing

For example: (names supposed to be written in italics)
- The most commonly known yeast is Saccharomyces cerevisiae
- It is common to abbreviate the genus name: S. cerevisiae
- Saccharomyces paradoxus is another species of that is a member of the same genus as cerevisiae

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6
Q

What are the 3 domains ?

A

BAE

Bacteria
Archaea
Eukarya

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7
Q

What is taxonomy ?

A
  • is the practice of biological classification
  • involves placing organisms into a series of categories/taxa
  • by grouping - easier to understand/remember
  • several different ranks within hierarchical classification system
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8
Q

What is the highest rank in the classification system

A

Domain

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9
Q

What has a major role in the classification of organisms into the 3 domains?

A

Cell type

  • Prokaryotic cells are easily distinguishable in that they lack a nucleus
  • Eukaryotic cells have compartmentalised structures, with at least their genetic material segregated from the rest of the cells in a nucleus
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10
Q

Based upon molecular analysis of RNA genes in particular, scientists have realised that using cell type to classify organisms is insufficient as… ?

A

Prokaryotes could be divided into 2 separate groups (domains)

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11
Q

What are the 3 domains - labelled with Prokaryote / Eukaryote

A

Bacteria (prokaryotes)
Archaea (prokaryotes)
Eukarya (eukaryotes)

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12
Q

Archaea

A
  • referred to as extremophile prokaryotes
  • 1st discovered living in extreme environments - not all archaea do
  • have no nucleus - SO PROKARYOTIC
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13
Q

unique properties of Archaea for them being separated from being classified as bacteria

A
  • unique lipids being found in membrane of their cells
  • no peptidoglycan in cell walls
  • ribosomal structure - more similar to eukaryotic ribosome than bacteria
  • similar size range to bacteria
  • DNA transcription more similar to that of eukaryotes
    EG: Halobacterium salinarum are a species of the archaea domain that can be found in environments with high salt concentrations like the Dead Sea
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14
Q

Bacteria

A
  • have prokaryotic cells - contain no nucleus
  • vary in size over wide range
  • divide by binary fission
  • EG: Staphylococcus pneumoniae is a bacteria species that causes pneumonia
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15
Q

Eukarya

A
  • have nuclei and membrane-bound organelles
  • vary massively in size from single-celled organisms
  • divide by mitosis
  • reproduce sexually/asexually
  • EG: Canis lupus also known as wolves
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16
Q

What are the main differences between Archaea and Bacteria?

A
  • Membrane lipids:
    The membrane lipids of Archaea consist of branched hydrocarbon chains bonded to glycerol by ether linkages

The membrane lipids of Bacteria consist of unbranched hydrocarbon chains bonded to glycerol by ester linkages

  • Ribsomal RNA:
    Both have 70s ribosomes
    Archaea has smaller 70s subunit - more similar to subunit in Eukaryotic ribosomes than Bacteria

base sequence of rRNA in Archaea more similar to rRNA of Eukarya than bacteria

primary structure of ribosome proteins in Archaea show more similarity to ribosome proteins in Eukarya than bacteria

  • Cell wall composition
    CELL WALL ALWAYS PRESENT FOR BOTH
    Bacteria - cell wall peptidoglycan
    Archaea- do not contain peptidoglycan
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17
Q

Order of the hierarchical classification system

A

Kings Play Chess On Fancy Gold Squares
Kingdom Phylum Class Order Family Genus Species

EG
A wolf belongs to the following taxonomic groups:
Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Canidae
Genus: Canis
Species: lupus

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18
Q

The domain Eukarya can be divided into what 4 kingdoms ?

A

FAPP

Fungi
Animalia
Plantae
Protoctista

  • organisms from each of 4 kingdoms have distinct characteristics and features - have cells with membrane-bound nuclei separating genetic material from the cytoplasm, and compartmentalisation within their cells as a result of the presence of other organelles
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19
Q

Kingdom Protoctista

A

Eukaryotic
- can exists as single-celled organims or as a group of similar cells

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20
Q

what is a group of protoctista known as?

A

protozoa possess cells similar to animal cells

  • cells have no cell wall
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21
Q

what is the name of another group of Protoctista known as?

A

Algae
- possess cells similar to plant
- cells have cellulose cell walls and chloroplast

Stentor roseli is a protoctist that has flagella all over its body which help it feed and move

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22
Q

Kingdom Fungi

A

All Eukaryotic
- non-cellulose cell walls - made of polysaccharides chitin and glucans
- no cilia
- are heterotrophs - use organic compounds made by other organisms as their source of energy and molecules for metabolism
- they obtain this energy and carbon by digesting dead/decaying matter extracellularly or from being parasites on living organisms

  • reproduce using spores that disperse onto ground nearby
  • have a simple body form:
  • can be unicellular
  • some consist of long threads-hyphae that grow from main fungus body
  • larger fungi possess fruiting bodies that release large numbers of spores
  • mould on bread - fungus
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23
Q

Kingdom Plantae

A
  • multicellular eukaryotic organisms
  • all have cell walls - cellulose
  • large usually permanent vacuoles - provide structural support
  • able to differentiate into specialised cells to form tissues and organs
  • possess chloroplast - enable photosynthesis
  • sometimes flagella
  • are autotrophs - can synthesize their organic compounds and molecules for energy use and building biomass from inorganic compounds
  • have complex body forms - have branching systems above and below the ground.

Bristlecone pines are found in the USA, it is estimated that some of them could be 3000 years old

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24
Q

Kingdom Animalia

A
  • multicellular eukaryotic organisms
  • able to differentiate into many different specialised cell types that can form tissues and organs
  • have small temporary vacuoles eg lysosome
  • no cell wall
  • sometimes cilia
  • are heterotrophs - have a wide range of feeding mechanisms
  • have a wide range of body forms - communication with their complex body forms takes place through nervous system and chemical signalling.

Blue whales are the largest living animal species

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25
Q

Viruses

A
  • microorganisms only seen using e microscope
  • no cellular structure - acellular + no metabolism
  • hijack DNA replication machinery in host cells
  • energy for replication provided by respiration in host cell
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26
Q

Why do viruses sit outside of the three-domain classification system?

A

they possess none of the characteristics features used for classifying organisms.

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27
Q

how are viruses classified?

A

it’s classified according to the type of nucleic acid (RNA/DNA) their genome is made from - where it is single-stranded or double-stranded

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28
Q

in cellular organisms eg animals and plants which one is single stranded and which one is double stranded DNA or RNA ?

A

DNA- ALWAYS double-stranded
RNA- USUALLY ALWAYS single-stranded

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29
Q

However in viruses DNA and RNA can either be …?

A
  • single-stranded or double-stranded

As a result 4 groups of viruses exist:

  • DNA single-stranded viruses
  • DNA double-stranded viruses
  • RNA single-stranded viruses (this is the type of genome of SARS-CoV-2, the virus responsible for the COVID-19 pandemic)
  • RNA double-stranded viruses
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30
Q

Define ecosystem

A

an ecosystem is a relatively self-contained, interacting community of organisms, and the environment in which they live with which they interact

  • There are both living (biotic) components and non-living (abiotic)components within an ecosystem
  • Ecosystems vary greatly in size and scale
    Both a small pond in a back garden and the open ocean could be described as ecosystems
    A human being could also be described as an ecosystem; there are thousands of species of bacteria living on and in every person

Ecosystems vary in complexity:
A desert is a relatively simple ecosystem
A tropical rainforest is a very complex ecosystem

No ecosystem is completely self-contained as organisms from one ecosystem are often linked to organisms from another
For example, birds are able to fly long distances to feed from multiple ecosystem

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31
Q

Define habitat

A

a habitat describes the place where a
species lives within an ecosystem

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32
Q

Define niche

A

a niche is the role of an organism in an
ecosystem

It encompasses where in the environment the organism is, how it gets its energy and how it interacts with other species and its physical environment
This is how an organism fits into the ecosystem

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33
Q

Define biodiversity

A

A study of all the variation that exists within and between all forms of live

  • looks at the range and variety of genes, species and habitats within a particular region.
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34
Q

Biodiversity can be assessed at 3 different levels

A
  • The number and range of different ecosystems and habitats
  • The number of species and their relative abundance
  • The genetic variation within each species
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35
Q

Why is Biodiversity important?

A

for the resilience of ecosystem, in that it allows them to resist changes in the environment.

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36
Q

Ecosystem/habitat diversity

A
  • is the range of different ecosystems/habitats within a particular area/region

-if there is a large number of different habitats within the area it has high biodiversity
EG: coral reef. They are very complex with lots of microhabitats and niches to be exploited

  • if only 1/2 different habitats then area has low biodiversity
    EG: Large sandy deserts typically have very low biodiversity as the conditions are basically the same throughout the whole area
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37
Q

Species Diversity

A
  • looks at the number of different species in an ecosystem + also the evenness of abundance across the different species present
  • the greater the number of species in an ecosystem, and the more evenly distributed the number of organisms are amongst each species, then the greater the species diversity
    EG: an ecosystem can have a large number of different species but for some species, there may only be 3 or 4 individuals. As a result, this ecosystem does not necessarily have high species diversity.
  • Ecosystems with high species diversity are usually more stable than those with lower species diversity as they are more resilient to environmental changes.
    EG: in the Pine forests of Florida, the ecosystem is dominated by one or two tree species. If a pathogen comes along that targets one of the two dominant species of trees, then the whole population could be wiped out and the ecosystem it is a part of could collapse
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38
Q

Define species richness

A

the number of species within an ecosystem

An ecosystem - tropical rainforests has very high number of different species so species rich

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39
Q

Define genetic diversity

A
  • the diversity of alleles and genes in the genome of species
  • species not necessarily have same alleles for each gene
  • measured by working out the proportion of genes that have more than one form (allele) and how many possible alleles each gene has
  • there can be genetic differences/diversity between populations of the same species - this may be due to 2 populations occupying slightly different ranges in their habitat and so are subject to slightly different selection pressures that affect the allele frequencies in their populations
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40
Q

genetic diversity within a single population has also been observed

A
  • this diversity in a species is important as it can help the population adapt to, and survive, changes in the environment
  • changes could be in biotic factors - new predators, pathogens and competition with other species
  • or abiotic factors - temp, humidity and rainfall
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41
Q

define sampling

A

method of investigated the abundance and distribution of species and populations

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42
Q

what are the 2 types of sampling

A

Random and Systematic

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43
Q

random sampling

A
  • the positions of the sampling points are completely random or due to chance
  • This method is beneficial because it means there will be no bias by the person that is carrying out the sampling that may affect the results
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44
Q

systematic sampling

A
  • the positions of the sampling points are chosen by the person carrying out the sampling
  • There is a possibility that the person choosing could show bias towards or against certain areas
  • Individuals may deliberately place the quadrats in areas with the least species as these will be easier and quicker to count
  • This is unrepresentative of the whole area
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45
Q

When a sampling area is reasonably uniform or has no clear pattern to the way the species are distributed - which sampling method should be used?

A

random

46
Q

distribution of species

A

describes how it is spread throughout the ecosystem

47
Q

abundance of a species

A

is the number of individuals of that species

48
Q

The distribution and abundance of a species in an area can be assessed using which different practical methods?

A
  • Frame Quadrats
  • Line and Belt Transects
  • Mark-release-capture
49
Q

Frame quadrats

A
  • square frames called quadrats can be used to mark off the area being sampled
  • Quadrats of different sizes used depending on what is being measured and what is most suitable in the space the samples are being made in
  • Quadrats must be laid randomly in the area to avoid sampling bias
  • This random sampling can be done by converting the sampling area into a grid format and labelling each square on the grid with a number
  • Then a random number generator is used to pick the sample points
  • Once the quadrat has been laid on the chosen sample point the abundance of all the different species present can be recorded
50
Q

Results from quadrats

A
  • The results from the quadrats can be used to calculate the predicted frequency and density of a species within an area
  • Species frequency is the probability that the species will be found within any quadrat in the sample area
  • The number of quadrats that the species was present in is divided by the total number of quadrats and then multiplied by 100
    EG: if bluebells were found in 18 out of 50 quadrats the species frequency would be (18/50) x 100 = 36%

-Species density indicates how many individuals of that species there are per unit area

The number of individuals counted across all quadrats is divided by the total area of all the quadrats
EG: if 107 bluebells were found across 50 quadrats that are 1m2 each the species density would be 107/50 = 2.14 individuals per m2

It can sometimes be difficult to count individual plants or organisms. When this is the case percentage cover of the species within the quadrat can be estimated instead

The quadrat is divided into 100 smaller squares. The number of squares the species is found in is equivalent to its percentage cover in that quadrat
EG: if grass is found in 89 out of 100 squares in the quadrat then it has a percentage cover of 89%

51
Q

when there are changes in physical conditions eg- changes in altitude, soil pH, or light intensity when investigating the species distribution in these kinds of areas which sampling method should you use?

A

Systematic sampling

52
Q

Using transects can help to show how ..

A

species distribution changes with different physical conditions in the area.

53
Q

what is a transect?

A

is a line represented by measuring tape, along which sample are taken

54
Q

For a line transect

A
  • lay out measuring tape in a straight line across the sample area
  • at equal distances along the tape record the identity of the organisms that touch the line for eg every 2m
  • produces qualitative data
55
Q

For a belt transect

A
  • Place quadrats at regular intervals along the tape and record the abundance of each species within each quadrat
  • produces quantitative data
56
Q

Mark-release-capture

A
  • method used for mobile species
  • used in conjunction with Lincon Index

-1st large sample is taken. As many ind as possible caught, counted and marked in a way they won’t affect their survival
- returned to their habitat and allowed to randomly mix with the rest of the population
- when sufficient amount of time has passed another large sample is captured
- number of marked and unmarked ind within samples are counted
- proportion of marked to unmarked ind is used to calculate an est of population size.

formula for the calculation is:
N = n1 x n2 / m2

Where:
N = population estimate
n1 = number of marked individuals released
n2 = number of individuals in the second sample (marked and unmarked)
m2 = number of marked individuals in the second sample

EG:
No. caught and marked in first sample (n1) = 236
No. caught in second sample (n2) = 244
No. of marked individuals in the second sample (m2) = 71
Using the equation: N = n1 x n2 / m2 = 236 x 244 / 71 = 811
N (estimated population size) = 811

57
Q

define correlation

A
  • association/relationship between variables
  • There may be a correlation between species; for example, two species always occurring together
  • There may be a correlation between a species and an abiotic factor, for example, a particular plant species and the soil pH
  • The apparent correlation between variables can be analysed using scatter graphs and different statistical tests
58
Q

define causation

A

occurs when one variable has an influence or is influenced by another

59
Q

In order to get a broad overview of the correlation between two variables the data points for both variables

A

Plot a scatter graph

60
Q

The correlation coefficient (r) indicates

A

the strength of the relationship between variables

61
Q

Perfect correlation

A

when all of the data points lie on a straight line with a correlation coefficient of 1 or -1

62
Q

Correlation can be

A

positive or negative

63
Q

if there is no correlation between variables

A

correlation coefficient will be 0

64
Q

The correlation coefficient (r) can be calculated to determine

A

whether a linear relationship exists between variables and how strong that relationship is

65
Q

Pearson linear correlation

A
  • statistical test that determines whether there is linear correlation between two variables

The data must:
- Be quantitative
- Show normal distribution

Method:
Step 1: Create a scatter graph of data gathered and identify if a linear correlation exists
Step 2: State a null hypothesis
Step 3: Use the following equation to work out Pearson’s correlation coefficient r

If the correlation coefficient r is close to 1 or -1 then it can be stated that there is a strong linear correlation between the two variables and the null hypothesis can be rejected

EG:
Null hypothesis: There is no correlation between the abundance of species A and species B.

Steps to calculate the correlation coefficient:

Step 1: Calculate xy

Step 2: Calculate x̅ and y̅ (means of x and y)

Step 3: Calculate nx̅y̅

Step 4: Find ∑xy

Step 5: Calculate standard deviation for each set of data Sx and Sy

Step 6: Substitute the appropriate numbers into the equation

66
Q

If there is an apparent relationship between two variables but the data does not show a normal distribution

A

Pearson’s linear correlation coefficient should not be used

67
Q

Spearmans rank correlation

A

determines whether there is correlation between variables that don’t show a normal distribution
Method:
Step 1: Create a scatter graph and identify possible linear correlation
Step 2: State a null hypothesis
Step 3: Use the following equation to work out Spearman’s rank correlation coefficient r
Step 4: Refer to a table that relates critical values of rs to levels of probability

If the value calculated for Spearman’s rank is greater than the critical value for the number of samples in the data ( n ) at the 0.05 probability level (p), then the null hypothesis can be rejected, meaning there is a correlation between two variables

EG:
Step 1: Rank each set of data (rank 1 being the smallest data figure)

Step 2: Find the difference in rank between the two species, D

Step 3: Square the difference in rank, D2 (= 6)

Step 4: Substitute the appropriate numbers into the equation (remember n = 10)

Step 5: Refer to a table that relates values of rs to probability. Look for the 0.05 probability level with n = 10

68
Q

Once the abundance of different species in an area has been recorded the results can be used to calculate what?

A

the species diversity or biodiversity for that area

69
Q

Species diversity

A

looks at the number of different species in an area but also the evenness of abundance across the different species

70
Q

Simpson’s index of diversity (D)

A

can be used to quantify the biodiversity of an area

Where:
n = total no. of organisms for a single species
N = total no. of organisms for all species
To calculate Simpson’s Index:
Step 1: First step is to calculate n / N for each species
Step 2: Square each of these values
Step 3: Add them together and subtract the total from 1
The possible values of D are significant:
- The value of D can fall between 0 and 1
- Values near 1 indicate high levels of biodiversity
- Values near 0 indicate low levels of biodiversity

71
Q

Extinction

A

when a species comes to an end or dies out

Mass extinction events have also occurred in the past where a very large number of species went extinct at one time
The rate of extinction during these periods are very high

72
Q

Past mass extinctions were likely caused by

A

major and sudden shifts in the environment such as an Ice Age or an asteroid hitting the earth

73
Q

Possible reasons for extinction include

A
  • Climate change
  • Competition
  • Introduction of species
  • Hunting by Humans
  • Degradation and loss of habitats
74
Q

Climate change

A
  • The large scale burning of fossil fuels by humans in recent years has led to a large increase in the levels of carbon dioxide in the atmosphere, creating the greenhouse effect
  • The increased carbon dioxide concentration in the atmosphere has had several knock-on effects on ecosystems around the world

-There has been an increase in the mean global temperature
- Sea levels are rising
- Ocean temperatures and acidity are rising
- Ice caps are melting

  • These knock-on effects have massively changed the habitats of some species, so much so that some are no longer able to survive in the new environmental conditions
  • For example, polar bears are struggling to survive as more of their habitat melts away earlier each year. The earlier melting of the ice caps means they have to swim further to reach seal populations that they hunt for food
75
Q

Competition

A
  • When there is a limited supply of resources within an area competition between individuals for the same resource can occur
  • The resources could be food, water, habitat and reproductive mates
  • Competition can exist within species and between species
  • Competition reduces the population size of a species
    For example, millions of years ago there were many different species of wild dog that lived in North America. When several cat species spread from Asia into North America there were high levels of competition between these carnivores. As a result, there are only nine species of wild dog that exist in North America today
  • Competition with humans has become a major problem for some species in the last 100 years as humans have taken their food, water and habitat
76
Q

Introduction of species

A
  • When humans colonised new land they would often exchange animal and plant species between their home country and the new land
  • These introduced species are non-native
  • Non-native species can be highly problematic as they often have no natural competitors, predators or pathogens that help limit population growth
  • Without these natural population checks, non-native species can massively increase in number
  • The large numbers of non-native species can negatively affect the native species through factors such as competition and disease
  • Grey squirrels have led to the decimation of the red squirrel population in the UK
  • Grey squirrels were introduced to the UK in 1876
  • They quickly grew in numbers
  • The larger grey squirrels compete with red squirrels for food
  • They also carry and transmit a disease known as squirrelpox which is fatal to red squirrels
77
Q

Hunting by humans

A
  • In the past humans would have hunted, killed and ate wild animal species in order to survive
  • Nowadays most of the meat that humans consume comes from domesticated livestock like cattle, sheep and chicken
  • The evolution of livestock has negated the need for many humans to hunt wild animals
  • Some humans in underdeveloped countries still have to hunt animals for survival
  • The hunting of wild animals is still common and has become a sport for some individuals
  • The rarer and more vulnerable species are often more desirable for a sport hunter
  • If too many individuals within a species are killed then the population can become so small that it is no longer able to survive
78
Q

Degradation & loss of habitats

A
  • This is the main cause of species extinction
  • Over recent years humans have aggressively destroyed animals habitats by cutting down forests, draining wetlands and polluting the water, soil and air
  • This is highly problematic as species are adapted to survive within their specific habitat that has particular environmental conditions
  • Without their habitat organisms will not get the resources they need to survive
  • As their habitat area gets reduced a species will:
  • Search for other suitable habitats
  • Compete with others for the remaining habitat
  • Eventually the range of habitat can become so small or non-existent that a species is not able to survive and goes extinct
    Exam Tip
79
Q

Biodiversity

A
  • is the range and variety of genes, species and habitats within a particular region

It is made up of three components:
Genetic diversity
Species diversity
Ecosystem diversity

80
Q

Global biodiversity has a

A

major impact on humans and all other species on the planet

81
Q

many reasons for maintaining biodiversity:

A
  • Moral and ethical
  • Ecological
  • Environmental
  • Economic
  • Aesthetic
  • Agricultural
82
Q

Moral & ethical reasons

A

Humans have a responsibility to reduce their impact on the planet and other species

83
Q

Ecological reasons

A

Biodiversity increases the stability of ecosystems

84
Q

Environmental reasons

A

Organisms provide essential environmental services (water cycle, nutrient cycle and absorption of CO2)

85
Q

Economic reasons

A

A range of organisms contribute to medicine, ecotourism, science and tech

86
Q

Aesthetic reasons

A

Humans take pleasure from the visual effects of biodiversity

87
Q

Agricultural reasons

A

Genetically diverse wild species can rescue crops from catastrophes

88
Q

Define endangered species

A

is a species that is being threatened with extinction

89
Q

Conservation of endangered species can be approached in several different ways

A

Ideally a species should be kept in their natural habitat as all the support systems they need to maintain life already exist there

National parks and marine parks are examples of conservation methods that do this

When it is not possible to do this endangered species can be captured and placed in captivity for conservation efforts
Zoos and botanic gardens take part in conservation programmes

Scientists have also come up with several methods to try and ensure the long-term survival of endangered species through frozen zoos and seed banks

90
Q

conservation method - National Parks role

A

Protecting endangered animal and plant species through strict regulations.
Increasing public engagement in conservation

91
Q

conservation method - Marine Parks role

A

Protecting endangered marine species through restrictions
- Increasing awareness

92
Q

conservation method - Zoos role

A

Captive breeding programmes for the reintroduction of animal species into the wild.
Research
Education

93
Q

conservation method - Botanic Gardens role

A

Captive breeding programs for the reintroduction of plant species into the wild
Research
Education

94
Q

conservation method - Frozen zoos role

A

Long term storage of animal genetic material at very low temperature

95
Q

conservation method - Seed banks role

A

Long term storage of plant seeds in a temperature-controlled environment.

96
Q

Endangered mammals tend to have

A

small and isolated populations

small populations are prone to inbreeding and inbreeding depression

97
Q

Inbreeding depression is

A

the reduction in fitness of a population due to breeding between closely related individuals and the resulting increased homozygosity

98
Q

When populations are isolated it can also be

A

difficult for individuals to find suitable reproductive mates

Previously large mammals were transported between zoos in captive breeding programs

Advantage: Humans were able to monitor the health of the mother and foetus
Disadvantage: It was highly expensive and unreliable as sometimes individuals would refuse to mate

Science has come up with several solutions for inbreeding and the lack of reproductive mates in endangered mammals

99
Q

IVF - in vitro fertilisation involves

A

the fertilization of an egg outside of the female body
For example in a test tube or petri dish

Method:
- A needle is inserted into the female’s ovaries and eggs are extracted
- The eggs are kept in a culture medium for a short amount of time
- Male semen is mixed with the eggs so fertilization can occur
- Several zygotes form and develop into embryos
- The embryos are placed in a culture for several days
- The embryos are transferred either into the mother, or another female

100
Q

Why is IVF advantageous over natural mating?

A

allows humans to control and confirm fertilization of the embryo

101
Q

Embryo transfer

A
  • Pregnancies are high risk for females; complications can arise which in some cases prove fatal
  • Since the population numbers of an endangered species are already very low each reproductive female is of very high value and importance
  • Embryo transfer can be used to avoid the risks of pregnancy for the vulnerable female so that she can provide many eggs for multiple offspring

Method:
- An egg belonging to a female of the vulnerable species is fertilized by the sperm belonging to a male of the same species

  • A zygote forms which develops into an embryo
  • After fertilization, the embryo is taken from the uterus of the female and transferred to a surrogate female
  • The embryo develops to full term and the offspring is born
  • The surrogate mother can be from another non-vulnerable species
  • This technique has been used to try and conserve populations of several different species of African antelope
102
Q

Surrogacy

A
  • A surrogate is any female that becomes pregnant with the embryo from another female and carries the embryo to full term
  • Surrogate mothers require hormone treatment before they receive an embryo
  • The hormones ensure that her uterus is in the right condition for the embryo to embed
  • There are multiple ways in which the embryo might have been conceived:
  • Naturally
  • Artificial insemination (semen from the male is injected into the uterus of the female)
  • IVF
  • A surrogate female can be the same or different species to the biological mother of the embryo
    If it is a different species it needs to be closely related to ensure compatibility of the embryo and uterus
103
Q

Define invasive species

A

A species that has moved into an ecosystem where it was previously unknown

  • can occur naturally as a result of a species migrating or expanding their habitat but most recorded incidents of invasive species have been caused by humans
  • Japanese knotweed is the UK’s most invasive non-native plant species- It grows at a rapid rate, breaking up tarmac and blocking out all sunlight for the native plant species
104
Q

Problems with invasive alien species

A

-will have evolved adaptations for survival in different environmental conditions so when they are introduced into the new ecosystem this can upset the balance

-In a new ecosystem invasive species will have little or none of the natural population controls that existed in their previous ecosystem:
- They will have no natural predators or competitors

-As a result they are able to increase in number at a rapid rate

  • As a result they are able to increase in number at a rapid rate
  • This can affect the processes within an ecosystem
  • Competition may occur between invasive species and native species that occupy a similar niche with the native species getting displaced or pushed to extinction. It could be competition for things such as prey, soil nutrients, light and space
  • Many invasive species can be over successful predators causing a massive decline in their prey species
  • Invasive species can introduce new diseases, to which the native species have no natural immunity
  • The biodiversity of an ecosystem is negatively impacted which reduces its productivity
  • Humans can also feel the knock on effects of an invasive species taking over an ecosystem
  • The spread of novel diseases and irritants of the skin / respiratory system directly affect human health
  • The economy of a country can be severely impacted by the costs of trying to control invasive species and their negative effects
  • In the past travel has been brought to a standstill by invasive species, with some plant species prone to blocking up waterways

The Cane Toad in Australia:
. An insect pest was destroying the crop and causing major economic losses for many farmers. It was decided that the non-native cane toad (from Hawaii) should be introduced so that it could act as a biological control. After a short period of time the numbers of cane toads increased rapidly due to a lack of natural predators and they spread into other habitats outside of the sugarcane plantations. This had a knock on effect on other species:

The cane toad is toxic when eaten. The northern quoll, which is an endangered marsupial carnivore, declined steeply in numbers as they preyed on the cane toad
Other amphibian species face increased competition for food and resources
The eggs of ground-nesting birds are often eaten by cane toads

105
Q

International cooperation is essential if

A

-conservation is to be successful

-There are several agreements and authorities that exist within and between countries with the aim of protecting and conserving species worldwide

106
Q

IUCN- The International Union for the Conservation of Nature is described as ..

A

“the global authority on the status of the natural world and the measures needed to safeguard it”

107
Q

What is one of the duties of the IUCN?

A

-carries out is assessing the conservation status of animal and plant species around the world

  • The IUCN has their own classification system
  • There are several different categories and levels that a species can fall into depending on their population numbers and the threats and risks to those populations
  • Scientists use data and modelling to estimate which category each species should be in
  • Animals that are on the IUCN Red List of Threatened Species™ can be seen online as this list is made public
108
Q

CITES - The Convention on International Trade in Endangered Species of Wild Flora and Fauna is a

A
  • a global agreement that has been signed by over 150 countries
  • Its aim is to control the trade of endangered species and their associated products
    For example, elephants and their ivory tusks
109
Q

CITES categorizes endangered and vulnerable species into three appendices:

A

Appendix I : species that are endangered and face the greatest risk of extinction (for example, the red panda)

Appendix II: species that are not currently endangered or facing extinction, but will be unless trade is closely controlled (for example, the venus fly trap)

Appendix III: species included at request of the country that is regulating trade of the species and trying to prevent its overexploitation (for example, the two-toed sloth in Costa Rica)

Scientists are continuously adding new species and reviewing the status of species already in the database

110
Q

what are the different trading regulations that apply to each appendix for CITES

A

For species in appendix I: all trade in the species and their associated products is banned

For species in appendix II: trade is only granted if an export permit has been issued by the involved countries

For species in appendix III: permits are required for regulated trade. Permits are easier to come by for species in this appendix

111
Q

There are several concerns about the efficacy of CITES listings

A

When the trade of a certain endangered species becomes illegal, its price increases

The increased economic value of the species can be a major incentive for people to break the law

Biology A level revision (11 decks)

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