4. Biodiversity and Natural Resources (1) Flashcards
Variety of life - 4.1 - 4.6 + 4.16
Biodiversity
The variety of living organisms within a habitat, ecosystem or biome
Species Diversity
The number and relative abundance of species in a biological community.
Genetic diversity
the variety of genes and alleles within a given species
Endemism
ecological state of a species being unique to a defined geographic location
Human effects on biodiversity
(deforestation)
Deforestation/ tar sands → removes habitats = loss of shelter, food → extinction, loss of biodiversity (reducing species diversity)
loss of trees= soil erosion, tree roots hold soils together.
Human effects on biodiversity (pesticides/ herbicides)
Pesticides → can be toxic to other animals, enter soil and can be carried to bodies of water via rainwater, which can be toxic to aquatic life. herbicides kill other plants which leads to loss of biodiversity.
Human effects on biodiversity
Eutrophication and fertilisers → fertilisers carried by rain water enter rivers and lakes → leads to nitrogen spike in water which kills aquatic animals. nutrients to some extent is good but the spike produces high levels of ammonia - toxic to aquatic organisms
Human effects on biodiversity - overgrowth of plants
Overgrowth of plants = removal of oxygen from water. More algae on water surface, blocks light from entering therefore no photosynthesis, no oxygen for aquatic organisms. They die, ammonia is released back into the water
Selective breeding + why it is problematic
humans choosing plants and animals with the most desirable traits/ most advantageous alleles) and breeding them more to enhance the expression of these traits over many generations, increasing desirable allele frequency this leads to a loss in genetic diversity of farm animals, which leads to a loss in biodiversity.
Species richness
The number of different species in a community
Species abundance
The number of individuals of each species (species population size)
Diversity index equation
uses the number of species (species richness/ N) and the number of individuals in each species (species abundance / n )
D = N(N-1) / sum of n(n - 1)
Gene pool
the combination of all the genes (including alleles) present in a reproducing population or species
Habitat
an area where one or more organisms live
Community
All of the populations of different species living and interacting in a place at the same time
Ecosystem
The dynamic interaction between all the living (biotic) and non living (abiotic) factors in a given area.
Population
All the individuals of a species living within a specific area. Individuals in the same species can interbreed.
Greater variety of alleles present in gene pool =
greater genetic diversity
Phenotype
The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment
Genotype
all the alleles and organism has on its chromosomes.
Relationship between base sequences and genetic diversity
The greater the difference in base sequences = the greater the number of different alleles = greater the genetic diversity
relationship between phenotypes and genetic diversity
Greater number of phenotypes ⇒ higher genetic diversity
Heterozygosity index
heterozygotes have different alleles at their particular locus. Higher proportion of heterozygotes = greater genetic diversity, heterozygosity index can be calculated using this:
H = number of heterozygotes/ number of individuals in the population
Niches
Within an ecosystem, every organism occupies a specific ecological niche.
Niche - the role a species has with its environment. This includes its interactions with the biotic and abiotic
What happens if two species have the same niche?
Competition
Behavioural adaptations
ways that the species acts to improve survival chances (i.e. possums playing dead, mating rituals)
Physiological Adaptations
processes inside an organisms body that help its chances of survival (i.e. brown bears hibernating)
Natural selection
[some organisms are better adapted to survive and pass on their characteristics]
mutations provide introduction of new alleles
selection pressures => competition
advantageous alleles more likely to survive + are able to reproduce to pass down alleles.
non-advantageous alleles less likely to survive and reproduce. They get outcompeted
advantageous alleles reproduce, pass down alleles for generations increasing allele frequency over time
= evolution
Anatomical adaptation
structural features of an organisms body that increase its chances of survival (i.e.. otters have streamlined shape to help them glide through the water.)
Evolution
change in allele frequencies over time
Divergent evolution
two or more species sharing a common ancestor become more different over time
Adaptive radiation
Evolutionary pattern, many species evolving from a single ancestral species
Convergent evolution and its problem
Process by which unrelated organisms independently evolve similarities when adapting to similar environments
= makes classification harder
Species
Organisms that can reproduce to produce fertile offspring
Speciation
Two species become reproductively isolated and can no longer reproduce to produce fertile offspring
4 causes of speciation
seasonal changes → leading to different m flowering or mating seasons > sexually active at different times of year
mechanical changes → changes in genitalia preventing successful mating
Behavioural differences → differences in courtship behaviours that are not attractive to other population.
Geographical isolation also
conditions of the hardy-weinberg principle
…that it is a large population with no immigration, emigration, mutations or natural selection. There must be random mating
Hardy Weinberg equation
PREDICTING ALLELE FREQUENCY
p+q = 1
p ⇒ frequency of the dominant allele
q ⇒ frequency of the recessive allele.
p^2 + 2pq +q^2 = 1
p^2 = frequency of the homozygous dominant genotype
2pq = frequency of the heterozygous genotype
q^2 = frequency of the homozygous recessive genotype
Species evenness
A measure of the relative abundance of the different species within a given area
Taxonomy
classification of organisms
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
[Did King Phillip Come Over For Good Soup]
What is classification based on
Classification based on on observable phenotypes, genotypes and relations to other species. for example, anatomical, physiological, behavioural characteristics.
Classification for characteristics you cannot see/ are not observable visible
DNA profiling to find similarities in organisms’ DNA sequence to help in classification.
Phylogeny
Evolutionary history of a species or a group of organisms
What does phylogeny tell us?
It tells us which species are related and how closely related they are
Molecular Phylogeny
Looks at DNA and proteins to see how closely related organisms are
Process of new taxonomic groupings
New data has to be evaluated by other scientists to ensure experiments were designed properly and if conclusions are fair
Prokaryotae Kingdom
(Bacteria) Prokaryotes, unicellular, no nucleus, less that 5micrometres
Protoctista Kingdom
(Algae, Protozoa) eukaryotic cells, live in water, single celled/ simple multicellular organisms.
Fungi Kingdom
(Moulds, Yeasts, Mushrooms) - eukaryotic, chitin cell wall, saprotrophic (absorb substances from dead or decaying organisms)
Plantae Kingdom
(Mosses, ferns, flowering plants) eukaryotic, multicellular, cell walls made of cellulose, can photosynthesise, contain chlorophyll, autotrophic (can produce their own food)
Animalia Kingdom
(insects, fish, mammals, birds, nematodes, molluscs) - eukaryotic, multicellular, no cell walls, heterotrophic (consume plants and animals)
Zoo’s contribution to conservation
captive breeding, reintroduction to the wild programmes
Captive breeding
species that are endangered or already extinct in the wild can be bred together in zoos to increase their numbers if they are critically low
Issues with captive breeding
animals could have problems breeding outside their natural habitat which is hard to recreate in an artificial setting, cruelty/ ethical concerns
Reintroduction to the wild
increasing numbers in wild/ conserve/ bring back from the brink of extinction
helps organisms that prey on animals being reintroduced to the wild.
contributes to restoring habitats.
Problems with reintroduction into the wild
new diseases being introduced, behavioural issues (such as communication, finding food) especially for adults introduced into the wild. Young animals have time to acclimatise
Seedbanks
store seeds from different species of plants, conserving biodiversity and genetic diversity by storing the seeds of endangered plants (therefore conserving different alleles)
What conditions do seedbanks need and why.
cool, dry conditions are needed for storage so seeds can be kept for a long time.
What are some tests seedbanks do?
Testing the seeds for viability. (seeds are planted, grown and new seeds are harvested to put back into storage.)
Also helpful in the case of famines
Advantages of seedbanks
cheaper to store than fully grown plants, large numbers of seeds can be stored because they take up less space. less labour needed.
Seedlings can be stored anywhere whereas whole plants would need to be store din places similar to its original habitat. Seeds less likely to be damaged by disease or natural disaster than plants
Disadvantages of seedbanks
testing for viability can be expensive and time consuming
Too expensive to store all types of seeds
difficult to collect all seeds, some grow in remote locations
Seedbank contribution to scence
Seeds can be used to research new crops, medical research and new materials
studying how seeds can be successfully grown is helpful for reintroducing them into the wild
Why are seedbanks not representative
sample comes from a small interbred population
Zoos contribution to science
increases knowledge about the behaviour, physiology and nutritional needs of animals, contributing to conservation efforts in the wild
zoos carry out studies not possible in the wild ⇒ reproductive and nutritional studies
Disadvantage of zoos
Disadvantage - the way animals act in captivity is different to how they act in the wild
