Biodiversity Flashcards
What is Biodiversity?
variety in an ecosystem
variety of habitats and variety of species
What is Species Diversity?
number of different species
number of individuals for each species
What is Genetic Diversity?
variety of alleles in a species population
the larger number of individuals in a species, the larger the genetic diversity
Benefit of high species diversity?
Stable ecosystem
each species is less likely to become extinct (due to high genetic diversity)
& if a species does become extinct it will not affect the food chain as there are other species available
How to measure Species Diversity for an area?
Species Diversity Index
takes into account the number of different species and how many individuals there are for each species
the larger the species diversity index, the larger the species diversity
How does deforestation lower species diversity?
(deforestation is the removal of trees for wood & space)
decreases plant species diversity
less variety of habitats
less variety of food sources
decreases animal species diversity
How does agriculture/farming lower species diversity?
deforestation to make space for farm
only grow a few plants & keep a few animal species
selectively breed plants & animals
use pesticides to kill other species
What is Classification?
placing organisms into groups
What is Hierarchical Classification?
large groups divided into smaller groups with no overlap
domain, kingdom, phylum, class, order, family, genus, species
What is Binomial Naming System?
using Genus name and Species name to name organism
Genus name first in capital, Species name second in lower case
e.g. tiger = Felix tigris
What is a Species?
a group of individuals with similar characteristics that can interbreed to produce fertile offspring
Why are the offspring from 2 different species mating infertile?
offspring will have a odd number of chromosomes
therefore, cannot perform meiosis, cannot produce gametes
example: horse + donkey = mule,
mule is infertile,
horse has 64 chromosomes/donkey has 62 chromosomes,
horse gamete has 32 chromosomes/donkey gamete has 31 chromosomes,
therefore, mule has 63 chromosomes
What is Phylogenetic Classification?
based on evolutionary relationships – how closely related different species are and how recent a common ancestor they have
3 ways of comparing relationship between different species?
- DNA Hybridisation
- Amino Acid sequence
- Protein Shape
what is DNA Hybridisation?
comparing DNA base sequence
AA Sequence?
comparing AA sequence for the same protein (e.g. haemoglobin in mammals)
protein shape?
comparing shape of the same protein (e.g. albumin) using immunological technique
What is Variation?
difference in characteristics between organisms
What is Variation?
difference in characteristics between organisms
Types of Variation?
intraspecific = differences between organisms of the same species
interspecific = differences between organisms of different species
Causes of Intraspecific Variation?
Genetic Factors = same genes but different alleles (allele are different type/forms of genes)
Environmental Factors
Causes of Interspecific Variation?
Genetic Factors = different genes and different alleles
Environmental Factors
Types of Characteristics?
Discontinuous and Continuous
Properties of Discontinuous Characteristics?
characteristics fall into certain groups with no overlap (e.g. blood group) – determined by genetics only (a single gene)
Properties of Continuous Characteristics?
characteristics show a range (e.g. height) – determined by genetics (a few genes, polygenes) and environment
What is Genetic Diversity?
genetic variation, the variety of alleles within a population of a species
Benefit of high genetic diversity?
species able to adapt with changes in the environment e.g. if a new disease arises, some individuals will have characteristics to survive, and will reproduce passing on their alleles, so the species does not become extinct
What can lower genetic diversity?
small population size (e.g. founder effect – where the numbers start low, or genetic bottleneck – where the numbers decrease)
What is natural selection and adaptation?
variation in population of species
(genetic diversity/genetic variation/variety in gene pool)
new alleles arise by random mutation
environment applies a selection pressure on the population
those with favourable characteristics/favourable alleles/selection advantage/better adapted survive, the others die [natural selection]
the ones that survive will reproduce, passing on their favourable alleles
if this happens for many generations, then that characteristic will become most common – the allele will become more frequent [adaptation]
What are the 2 types of selection?
stabilising and directional
What is stabilising selection?
when the environment favours those with the most common characteristic – those on the extreme dies out
the common characteristic increases in proportion
the range (standard deviation) will reduce
What is directional selection?
when the environment favours those individuals with characteristics on one of the extremes
over time this will become the most common characteristic
normal distribution will shift to that extreme
What is directional selection?
when the environment favours those individuals with characteristics on one of the extremes
over time this will become the most common characteristic
normal distribution will shift to that extreme
How to carry out DNA Hybridisation?
- take DNA from 2 species to be compared
- radioactively label one of the DNA
- heat both sets so double strand separates
- cool so single strands join together
- look for Hybrid DNA (one strand from species A, one strand from species B)
- identify Hybrid DNA by 50% radioactivity
- heat Hybrid DNA to measure similarity
results of DNA hybridisation?
-higher temperature required
-more hydrogen bonds present
-more complementary base pairing
-more similar the base sequence
-more similar the species
-more closely related
-more recent a common ancestor
results of AA sequencing?
-more similar the AA sequence
-more similar the DNA base sequence
-more similar the species
-more closely related
-more recent a common ancestor
How to carry out protein shape?
- comparing species A and species B
- take albumin from species A
- place in a blood of rabbit
- rabbit will make antibodies against albumin of species A
- takes these antibodies and place in blood from species B
- if the albumin in species B has a similar shape to species A, the antibodies will bind to form antigen-antibody complexes, this will then form a
precipitate
results of protein shape?
-more precipitate
-more complexes
-more similar shape
-more similar the species
-more closely related
-more recent common ancestor
why is comparing base sequence better than comparing amino acid sequence?
- DNA sequence provides information on INTRONS
- triplet code is DEGENERATE
how do courtship behaviours help an organism reproduce?
- enable members to identify their own species
- use similarities in physical
characteristics and behaviours
- prevents cross breeding and infertile
offspring being produced - identifying a mate that is capable of breeding
- both partners need to be sexually
mature, fertile and receptive to mating - forming pair bonds
- lead to successful breeding
- successful raising of the offspring - synchronising mating seasons
- ensure maximum chance of
fertilisation
- males show courtship behaviour to
determine whether the female is
receptive (fertile state)
- if female responds with correct
courtship behaviour then mating will
take place
equation for species diversity index?
d= N(N-1)/ Σn(n-1)
N= total number of organisms of all species
n= total number of organisms of each species
what is the difference between index of diversity and species richness?
- species richness only takes into account the number of different species in a particular area
- index of diversity takes into account the number of species in a community and the number of individuals in each species
How to calculate possible number of different combination of chromosomes following meiosis, without crossing over?
2^n
N= number of homologous pairs
