SL Bio Unit 10: Evolution and Diversity
how is everyone different
everyone is genetically different
identical twins have the least variation
people acquire differences through mutations and environmental factors
species
group of organisms with shared traits
Carl Linnaeus
studied morphology and taxonomy, created taxonomical system
binomial naming system
morphological species concept
idea that species are a group of organisms that share a particular outer form and inner
structure (Linnaeus)
binomial naming system
genus + species
1. genus has capital letter
2. species are all lowercase
3. binomial in italics
4. after used once, it can be abbreviated to the first letter of genus name and full
species name
biological species concept
a species is a group of organisms that can breed and have fertile offspring
exceptions to biological species concept
asexual organisms, conifers, ligers and tigons
population
group of organisms of the same species living in the same area at the same time
speciation
splitting of one species into two or more, gradual
# of chromosomes of chimpanzees
48 (2 more than humans)
why do species have different numbers of chromosomes
during evolution, the chromosome number can decrease if chromosomes fuse, or
increase if they split, or even double in number (rare)
karyogram
Image of the chromosomes of an organism, arranged in homologous pairs of
decreasing length.
how are chromosomes classified in a karyogram
banding differences, size, position of the centromere
karyotype
characteristic types of chromosomes in a species
how do differences in chromosome numbers between humans and chimpanzees
give evidence of evolution
humans have 46, chimpanzees have 48
theories that human chromosomes 2 is a fusion of chimp's 12 and 13
evidence that they come from a common ancestor
, genome
all the genetic info of an organism
genome size
size varies by DNA amount
measured in base pairs or units of mass
larger genomes can have lots more non-functional DNA
how are genome size and organism complexity related
there is a positive correlation but not directly proportional
what causes genetic variation
alleles and mutations (single nucleotide polymorphisms)
whole genome sequencing
determining the entire base sequence of an organism's DNA
now higher speed and lower costs so it's more common
uses of whole genome sequencing
research into evolutionary relationship
personalized medicine in the future?
lamarckism
leading evolutionary theory before Darwin in 1859
believed that acquired characteristics could cause evolution
repeatedly proved false
Darwinism
evolution is change in the heritable characteristics of a population
evolution
gradual divergence from common ancestor due to natural selection; causes changes in
the base sequence of DNA and RNA
artificial selection
repeatedly selecting and breeding individuals most suited to human uses
which creates more rapid changes: artificial selection or natural selection
artificial
homologous structures
similar anatomical position and structure despite differences in function
example of homologous structures
pentadactyl limbs (5 digits) - present in reptiles, birds, mammals, and amphibians with
different bone lengths and thicknesses
explanation of homologous structures
they were inherited from a common ancestor but have evolved in diverse ways to adapt
to different functions
vestigial structures
reduced structures that serve no function
example of vestigial structures
appendix
explanation of vestigial structures
the structures evolved from a common ancestor but evolved to gradually lose their
function
analogous structures
same function but different evolutionary origins
how is everyone different
everyone is genetically different
identical twins have the least variation
people acquire differences through mutations and environmental factors
species
group of organisms with shared traits
Carl Linnaeus
studied morphology and taxonomy, created taxonomical system
binomial naming system
morphological species concept
idea that species are a group of organisms that share a particular outer form and inner
structure (Linnaeus)
binomial naming system
genus + species
1. genus has capital letter
2. species are all lowercase
3. binomial in italics
4. after used once, it can be abbreviated to the first letter of genus name and full
species name
biological species concept
a species is a group of organisms that can breed and have fertile offspring
exceptions to biological species concept
asexual organisms, conifers, ligers and tigons
population
group of organisms of the same species living in the same area at the same time
speciation
splitting of one species into two or more, gradual
# of chromosomes of chimpanzees
48 (2 more than humans)
why do species have different numbers of chromosomes
during evolution, the chromosome number can decrease if chromosomes fuse, or
increase if they split, or even double in number (rare)
karyogram
Image of the chromosomes of an organism, arranged in homologous pairs of
decreasing length.
how are chromosomes classified in a karyogram
banding differences, size, position of the centromere
karyotype
characteristic types of chromosomes in a species
how do differences in chromosome numbers between humans and chimpanzees
give evidence of evolution
humans have 46, chimpanzees have 48
theories that human chromosomes 2 is a fusion of chimp's 12 and 13
evidence that they come from a common ancestor
, genome
all the genetic info of an organism
genome size
size varies by DNA amount
measured in base pairs or units of mass
larger genomes can have lots more non-functional DNA
how are genome size and organism complexity related
there is a positive correlation but not directly proportional
what causes genetic variation
alleles and mutations (single nucleotide polymorphisms)
whole genome sequencing
determining the entire base sequence of an organism's DNA
now higher speed and lower costs so it's more common
uses of whole genome sequencing
research into evolutionary relationship
personalized medicine in the future?
lamarckism
leading evolutionary theory before Darwin in 1859
believed that acquired characteristics could cause evolution
repeatedly proved false
Darwinism
evolution is change in the heritable characteristics of a population
evolution
gradual divergence from common ancestor due to natural selection; causes changes in
the base sequence of DNA and RNA
artificial selection
repeatedly selecting and breeding individuals most suited to human uses
which creates more rapid changes: artificial selection or natural selection
artificial
homologous structures
similar anatomical position and structure despite differences in function
example of homologous structures
pentadactyl limbs (5 digits) - present in reptiles, birds, mammals, and amphibians with
different bone lengths and thicknesses
explanation of homologous structures
they were inherited from a common ancestor but have evolved in diverse ways to adapt
to different functions
vestigial structures
reduced structures that serve no function
example of vestigial structures
appendix
explanation of vestigial structures
the structures evolved from a common ancestor but evolved to gradually lose their
function
analogous structures
same function but different evolutionary origins
