AS Biodiversity & Classification and Evolution/ A level Gentics,evolution,ecosystems Flashcards
what does habitat biodiversity include?
sand dunes, woodland,
meadows, streams
what is species biodiversity made up of?
species richness and species evenness
what is habitat biodiversity?
the range of different ecosystems or habitats within a particular area or region
what is species biodiversity?
the number of different species in an ecosystem, and also the evenness of abundance across the different species present
what is the species richness?
the number of species in a habitat
what is the species eveness?
the relative abundance of each species in an area
Why are both species evenness and species richness needed to assess biodiversity?
- Because they’re both needed to reveal dominance.
- Because high biodiversity is associated with both high species richness and high species evenness.
why are ecosystems with high species diversity usually more stable than those with lower species diversity?
because they are more resilient to environmental changes
what is the genetic diversity?
the diversity of alleles and genes in the genome of species
is it true that although individuals of the same species will have the same genes they will not necessarily have the same alleles for each gene?
Yes
how is the genetic diversity measured?
by working out the proportion of genes that have more than one form (allele) and how many possible alleles each gene has
why is genetic diversity important?
- it can help the population adapt to, and survive, changes in the environment
- The changes could be in biotic factors such as new predators, pathogens and competition with other species
- Or the changes could be through abiotic factors like temperature, humidity and rainfall
why is genetic diversity limited in populations that are very small or isolated?
- Inbreeding in small, isolated populations leads to a high proportion of individuals being homozygous (e.g. AA to aa) for many genes, resulting in lower genetic diversity
- This can mean that genetic diseases caused by recessive alleles can become more common in these populations
what is a species?
A group of individual organisms similar in
appearance, anatomy, physiology, biochemistry and genetics, whose members are able to interbreed freely to produce fertile offspring.
what is a habitat?
A place where an organism lives
what is biodiversity?
the variety of species in an area and the variety of habitats in an area.
why can we only give estimates for the number of species?
- New species are discovered all the time.
- Evolution and speciation are still occuring.
- We will never be sure that we have found all species.
- Species are endangered and some are becoming extinct
What are some factors that can lead to a species becoming extinct?
- Climate change
- Pollution
- Disease
- New pests/predators
How does climate change affect biodiversity?
- As the climate rapidly changes, species with
reduced variation will not be able to adapt to the
new selection pressures. - They are then left with the option of migration to
habitats more suitable to there species. - This means whole ecosystems are now effected
by the actions of humans and are either dying out
or shifting.
What can prevent organisms from migrating?
- Major human developments
- Agriculture
- Water availability
- Humans
How does climate change affect the spread of disease?
- Crops being grown in new areas mean new diseases and pests to combat.
- Longer growing seasons mean more pests and many will start to survive over winter.
- This also means the movement of pests causing human disease to spread to new areas (Malaria, Sleeping sickness)
How does climate change affect agriculture?
- Higher CO2 levels alter photosynthesis
- Longer growing seasons
- Greater evaporation of water hence more rain
- Change in rain distributions
- Loss of land due to rising sea levels
- Increased salinisation of soils
what is an ecosystem?
a community of animals, plants and bacteria interrelated with the physical and chemical environment
what is a habitat?
a place where an organism lives
what is a population?
all the organisms of one species, who live in the same place at the same time, and who can breed together
what is a community?
all the populations of different species, who live in the same place at the same time, and who can interact with each other
What are abiotic factors?
Non-living components of an ecosystem that affect other living things
what are producers?
organisms such as plants that produce biomass by converting energy from the sun into chemical energy in biological molecules
what are consumers?
heterotopic organisms in a food chain or web: primary consumers feed on plants and are eaten by secondary consumers. These in turn are eaten by tertiary consumers
what are decomposers?
bacteria, fungi, and some animals that feed on waste material or dead organisms
what are carnivores?
secondary and tertiary consumers that eat other animals
what are herbivores?
primary consumers, animals that eat plants
what are omnivores?
animals that eat producers and consumers
what is a niche?
the role of each species in an ecosystem
what is sampling?
a method of investigating the abundance and distribution of species and populations
what are the 2 different types of sampling?
- Random
- Non- random
describe random sampling
In random sampling, the positions of the sampling points are completely random or due to chance
describe non-random sampling
In non-random sampling the positions of the sampling points are chosen by the person carrying out the sampling
why is random sampling beneficial?
because it means there will be no bias by the person that is carrying out the sampling that may affect the results
what are the disadvantages of non-random sampling?
- There is a possibility that the person choosing could show bias towards or against certain areas
- Non-random sampling usually isn’t representative of the whole area
how can random sampling be used to measure the abundance and distribution of fast moving animals?
- Sweeping nets
- Pitfall traps
- Pooters
- Tullgren funnel
- Kick-sampling
what are the 3 main types of non-ransom sampling?
- opportunistic
- stratified
- systematic
Describe opportunistic sampling
- involves picking and choosing sampling locations based on various non-random factors. For example, students on a field trip may be told they can only collect samples from locations that are nearby, easy to reach, and safe. usually the weakest out of non-random because involves using the organisms you can easily access.
Define stratified sampling
- involves matching the number of sampling locations in a particular habitat with the relative proportion of area that habitat covers in the whole area being studied. For example, if 10% of a dense woodland being sampled is actually made up of grassy clearings, then 90% of the sample locations should be in the woodland habitat and 10% in the grass habitat
-
Define systematic sampling
- used when there is a clear change in the physical conditions across the area being studied
- an habitat is sectioned up into different sections and each is then sampled.
- most logical
what are sweeping nets?
are large, strong nets with a fine material (very small holes) that are used to catch flying insects and insects that live in long grass by sweeping the net back and forth through the grass
what are pitfall traps?
cans or jars that are buried in the ground that are used to catch ground-dwelling (often nocturnal) insects and other invertebrates as they fall into the trap
what are pooters?
small plastic or glass containers with two tubes sticking out that are used to suck up small insects and other small invertebrates. The first tube is placed over the insect and the second tube is used by the scientist to create suction
What 2 things can be looked at in order to identify the species diversity?
- species richness
- species evenness
is species richness a correct identifier of species diversity?
no, because the species richness does not take into account the number of individuals of each species
what statistical test can be used to work out the biodiversity of a habitat?
Simpsons index of biodiversity
what is the formula for simpsons index of biodiversity?
D = 1- (sum(n/N)^2)
Although individuals of the same species will have the same genes at the same loci they will not necessarily have ……
the same alleles for each gene
what is loci?
the specific linear position of a particular gene on a certain chromosome
what is the gene pool compromised of?
The gene pool is comprised of all the alleles of all the genes within a species
is it true that there can be genetic diversity both between different populations, and within a single polulation
yes
why is genetic diversity within a species important?
because it creates a larger gene pool which can help the population adapt, and survive changes in the environment
what change in the environment can help increase the gene pool?
biotic and abiotic chnages
Give some examples of biotic factors
- new predators
- pathogens
- competition with other species
Give some examples of abiotic factors
- temperature
- humidity
- rainfall
how can genetic biodiversity be assessed?
using the following equation:
proportion of polymorphic gene loci =
number of polymorphic gene loci/ total number of loci
what is polymorphic gene loci?
The number of loci that have two or more alleles
what do suitable populations for the following equation include (proportion of polymorphic gene loci =
number of polymorphic gene loci/ total number of loci )?
zoos (captive breeding),
rare breeds and pedigree animals.
what factors affect biodiversity?
-human population growth
-agriculture
-(monoculture) and climate change.
for how many years has the human population been growing exponentially?
for 150 years
why has the human population grown exponentially?
- Improved technology leading to an abundance of food = increase in birth rate
- Improved medicine, hygiene and health care = decrease in death rate
Why has the exponential human population growth impacted biodiversity?
- ## Greater use of natural resources are being used, which has harmful effect on many aspects of the environment, including aquatic and terrestrial ecosystems, and our atmosphere and climate.
How does climate change affect biodiversity?
- climate change is now occurring too fast for many species to be able to adapt to these changes, which could result in many species becoming extinct and a major decline in biodiversity
- Global warming (a result of climate change) is causing many species to move towards the poles or to higher altitudes.
- However, these species may not be able to compete with, or may even out-compete, the species already present in these habitats, with either result leading to decreased biodiversity
- Some species (such as plant species) may not be able to move or change their distributions fast enough to adapt to increasing temperature and may go extinct as a result
How is agriculture impacting biodiverstity?
- Many modern farming techniques negatively impact biodiversity.
- For example, Hedgerows represent an important habitat for many insects, small mammals and birds, which can nest there. As hedgerows are being increasingly removed, this habitat and the biodiversity it supports is lost
What reasons are there for maintaining biodiversity?
- Ecological : protecting keystone species
(interdependence of organisms) and
maintaining genetic resource - Economic: including reducing soil depletion
(continuous monoculture). - Aesthetic: including protecting landscapes.
what are the 2 main methods of increasing biodiversity?
in situ conservation and ex situ conservation
what are some examples of in situ conservation?
marine conservation zones and wildlife reserves
what are some examples of ex situ conservation?
seed banks, botanic gardens and zoos.
what is an endangered species?
a species that is being threatened with extinction
what is in situ conservation?
conservation carried out in the natural habitat
what is ex situ conservation?
conservation outside the natural habitat
what are the government restrictions on national parks?
- Humans access is strictly controlled
- Industrial activities such as agriculture and building are tightly regulated
- Hunting is limited or completely prohibited
what are marine conservation zones?
protected areas of water that have been set up for the conservation of endangered marine ecosystems and species
what is a problem with keeping organisms in zoos?
- Captive breeding of small species populations can reduce genetic diversity
- Certain animal species will not breed in captivity
- Not all zoos can provide adequate habitats for animals with specific needs
what are botanic gardens?
the plant equivalent of zoos. They use cuttings and seeds collected from the wild to establish a population of the endangered species in captivity
what is a seed bank?
a facility that conserves plant diversity by drying and storing seeds in a temperature controlled environment
what is the role of national parks in conservation?
protecting endangered animals and plant species through strict regulations. Also help increase public engagement in conservation.
what is the role of marine conservation zones in conservation?:
protecting endangered marine species through restrictions. Also helps increase awareness.
what is the role of zoos in conservation?
carry out captive breeding programmes for the reintroduction of animal species to the wild. Also promote research and education
what is the role of botanic gardens in conservation?
carry out captive breeding programmes for the reintroduction of plant species to the wild. Also promote research and education
what is the role of frozen zoos inconservation?
provide long term storage of animal genetic material at very low temperatures
what is he role of seed banks in conservation?
provide the long term storage of plant seeds in a temperature-controlled environment
what are the international and local conservation agreements
made to protect species and habitats?
- Convention on International Trade in Endangered
Species (CITES) - the Rio Convention on Biological
Diversity (CBD) - the Countryside Stewardship
Scheme (CSS)
what are the goals of CBD?
- The conservation of biological diversity by use of a variety of different conservation methods
- The sustainable use of biological resources
- The fair and equitable sharing of benefits arising from genetic resources
- The countries that signed the convention agreed to design and implement national strategies for the conservation and sustainable use of biodiversity, as well as to organise international cooperation and further international meetings
what are the goals of CITES?
- a global agreement that has been signed by over 150 countries
- aim is to control the trade of endangered species and their associated products
what are the goals of CSS?
- ## dating back to the 1980s that provided funding (i.e. a financial incentive) to farmers and private landowners in England who used environmental management strategies to protect and increase the natural biodiversity on their land
what is taxonomy?
the practice of biological classification
what does the biological classification system allow us to do?
The biological classification system enables us to arrange species into groups based on their evolutionary origins and relationships
How many taxonomic groups are there?
What are the 8 taxonomic groups?
-Domain
-Kingdom
-Phylum
-Class
-Order
-Family
-Genus
-Species
What’s a way of remembering the taxonomic hierarchy?
Kings Play Chess On Fancy Gold Squares
What is the domain of all eukaryotes?
eukarya
why 5 kingdoms can organisms be placed into?
-Prokaryotae
- Protoctista
- Fungi
- Plantae
- Animalia
what is a species?
a group of organisms that are able to reproduce to produce fertile offspring
What naming system is used for classification?
The binomial naming system
What is the first part of the binomial name?
The genus
What is the second part of the binomial name?
The species
Why is the binomial naming system useful?
because they allow for species to be universally identified - the binomial for a species is the same across the entire globe
Does the genus have a capital letter?
Yes
Does the species begin with a lower case letter?
Yes
What happens if it’s not possible to italiszie the binomial name?
It will be underlined
Why are plants photoautotrophs?
because they produce their own food using light
what is the highest rank in taxonomy?
domain
what are the 3 domains?
bacteria, archea, eukarya
why are archea sometimes referred to as extremophile prokaryotes?
were first discovered living in extreme environments
Why are archaea different from bacteria?
- Unique lipids being found in the membranes of their cells
- No peptidoglycan in their cell walls
- Ribosomal structure are more similar to the eukaryotic ribosome than that of the bacteria
is it true that before the three domains of life (Bacteria, Archaea and Eukarya) were introduced and then widely accepted as the highest rank in the classification of life on Earth, most people thought there to be five kingdoms at the top of the classification hierarchy?
Yes
What are the main features of prokaryota?
- Unicellular
- No nucleus
- Cell walls
- No mitochondria
- Divide by binary fission
What are the main features of Protoctista?
- Eukaryotic
- Can be unicellular or simple multicellular
- ## No cell walls
What are the main features of Fungi?
- Eukaryotic
- Chitin cell wall
- heterotrophs that obtain this energy and carbon by digesting dead/decaying matter
- reproduce using spores
- can be single-celled or multicellular
what are the main features of plantae?
- Eukaryotic
- Multicellular
- Cellulose cell wall
- ## autotrophic, produce their own food
what are the main features of animalia?
- eukaryotic
- multicellular
- have no cell walls
- ## heterotrophic
why is the 3 domain system used instead of the 5 kingdom system?
- Due to molecular evidence. The enzyme RNA polymerase is different in bacteria and archaea. Also, archaea have similar histone proteins to Eukarya.
- Due to cell membrane evidence. The bonds of the lipids in the cell membranes of the bacteria and archaea are different. The development and composition of flagella are also different.
What is homology?
a traditional biological classification system that grouped organisms based on the features that they shared
in the past, how did scientists try to determine the evolutionary relationships of species?
by looking at physical features that were the same, such as colour, shape, size
have DNA, RNA and protein sequencing allowed scientists to further investigate the evolutionary relationships between species?
Yes
what is phylogeny?
the term used to describe the evolutionary history of organisms. in other words, how closely related organisms are
what are phylogenetic trees?
diagrams that show the evolutionary relationships between different taxa
what 3 types of sequence data are used to investigate evolutionary relationships?
- DNA
- mRNA
- Amino acids of a protein
Cytochrome C
Cytochrome C is a short protein found in many species. The more similar the amino acid sequence of cytochrome C in 2 different species, the more closely related the species are likely to be.
Evolution, then variation
according to phylogenetics, what is a species?
the smallest group that shares a common ancestor
what is classifying organisms according to phylogeny called?
cladistics
what observations did Darwin make to help him develop the theory of evolution?
- All organisms produce more offspring than could ever actually survive
- Populations of organisms do fluctuate (change over time) but not significantly
- Populations of the same species of organisms show variation in characteristics between individuals (known as intraspecific variation)
- Offspring inherit characteristics from their parents
what are 2 key sources of evidence for the theory of evolution by natural selection?
- Fossil evidence
- DNA evidence/molecular evidence
What ae the key components of Darwin’s theory of evolution?
- Individuals within a population show variation in their phenotypes
- Selection pressures create a struggle for survival.
- Individuals with better adaptations are more likely to survive and have reproductive success.
- Over time, the proportion of the population possessing these advantageous alleles increases.
- Over generations, this leads to evolution as the favourable adaptations become more common in the population
Who realised that warning colours are used by some species to deter predators from eating them and that this is an example of an advantageous adaptation that had evolved by natural selection?
Alfred Russel Wallace
is it true that DNA sequence analysis and comparison can be used to create phylogenetic trees that show the evolutionary relationships between species?
Yes
did closely related species diverge more recently?
yes
is it true that organisms that have diverged away from each other more recently should have more similar DNA?
Yes, because less time has passed for changes in the DNA sequence to occur.
what is variation?
the differences that occur between 2 individuals
what is interspecific variation?
variation that occurs between different species
what is intraspecific variation?
variation that occurs between individuals of the same species
what is continuous variation?
when the individuals within a population vary within a range- there are no distinct categories
what is discontinuous variation?
where there are 2 or more distinct categories and no intermediates
what causes variation?
both genetic and environmental factors
what are alleles ?
different versions of genes
what is the phenotype?
the characteristics displayed by an organism
what does the standard deviation tell you?
how much the data is spread around the mean
what does a large standard deviation tell you?
that the values in a sample vary a lot
what does a small standard deviation tell you?
that the data is around the mean value and so only varies a little
what are selection pressures?
Environmental factors that affect the chance of survival of an organism
what 3 things can an adaptation be?
anatomical, physiological or behavioural
what causes adaptations to develop?
evolution by natural selection
what are anatomical adaptations?
Structural or physical features
what are physiological adaptations?
Biological processes within the organism
what are behavioural adaptations?
The way an organism behaves
why do organisms from different taxonomic groups sometimes show similar anatomical features?
- because the organisms have evolved in similar environments to fill similar ecological niches
- i.e marsupial and placental moles
what is an ecological niche?
what is convergent evolution?
where 2 species evolve similar characteristics independently of one another
what is genetic variation?
where individuals within a population have differences between their DNA base sequences
what does differences in the alleles possessed by individuals within a population result in?
differences in phenotypes
what do selection pressures result in?
increase the chance of individuals with a specific (more advantageous) phenotype surviving and reproducing over others
is it true that a population with a large gene pool or high genetic diversity has a strong ability to adapt to change?
yes
Natural Selection
- Mutations occur within a species.
- This causes variation.
- So, some individuals will develop a phenotype that gives them survival advantages.
- Individuals with advantageous characteristics are more likely to survive and reproduce.
- The gene (genotype) is then passed on to its offspring
Why may organisms from different taxonomic groups have similar features?
because they have evolved in similar environments and because they fill similar ecological niches
What 2 things cause evolution?
Natural selection and genetic drift
What is evolution?
The slow and continual change of organisms from one generation to the next
What 2 things cause evolution?
Natural selection and genetic drift
What is a population?
A group of organisms of the same species living in a particular area
What is the difference between natural selection and genetic drift?
In genetic drift, instead of environmental factors affecting which individuals pass on advantageous alleles, chance does
Describe genetic drift
1) Individuals within a population show variation in their phenotype.
2) By chance, the allele for one phenotype is passed on to the offspring, more than others.
3) So the number of individuals with the allele increases.
4) If by chance the same allele is passed on more often again and again, it can lead to evolution, as the allele becomes more common in the population.
When does evolution by genetic drift have a greater effect?
- in the case of genetic bottleneck
- in the case of the founder effect
What is genetic bottleneck?
An event that causes a big reducion in a population’s size, leading to a reduction in the gene pool
What is the founder effect?
When a few organisms from a population start a new population and there are only a small number of different alleles in the intial gene pool.
Hardy Weiberg Principle
predicts that the frequencies of alleles in a populaiton won’t change much from one generation to the next but only if:
- large population with no immigration, emigration, mutations, natural selection and only if there’s random mating.
is it true that high plant biodiversity supports drug discovery and development?
Yes
Explain how a pitfall trap can be set up and used to sample invertebrate biodiversity
- dig hole and place container in soil
- cover to protect from rain
- leave overnight
- Count the invertebrates
- Make sure to sample both areas randomly.
