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