All Organisms are Related Through their Evolutionary History
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- Created by: Ellen122
- Created on: 18-03-21 17:57
Taxonomy
The sorting of organisms into groups
Uses a hierarchal system created by Carl Linnaeus in 1753
Homologous characteristics are used to group similar organisms together
Different hierarchical levels are called taxa
Smallest taxon is a species defined as org
Uses a hierarchal system created by Carl Linnaeus in 1753
Homologous characteristics are used to group similar organisms together
Different hierarchical levels are called taxa
Smallest taxon is a species defined as org
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Taxa Largest to Smallest
Kingdom
Phylum
Class
Order
Family
Genus
Species
Phylum
Class
Order
Family
Genus
Species
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Rhyme of Taxa
King
Penguins
Can
Only
Find
Green
Sardines
Penguins
Can
Only
Find
Green
Sardines
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Human Taxa
Anaimal
Chordate
Mammals
Primates
Hominids
Homo
Sapiens
Chordate
Mammals
Primates
Hominids
Homo
Sapiens
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Incorrectly Classified
Before evolutionary relationships were correctly worked out
Ogranisms were often classified incorrectly due to having characteristics not typical of their closest relatives
Ogranisms were often classified incorrectly due to having characteristics not typical of their closest relatives
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Tenatative Nature of Classification
Exemplified by a fossil
Hallycigenia sp.
Discovered in the Burgess Shales of Canada
Rocks are known for exceptional preservation of Cambrain fossils including soft bodied animals such as worms
Charles Doolitte Walcott disvovered the Burgess Shale fossil b
Hallycigenia sp.
Discovered in the Burgess Shales of Canada
Rocks are known for exceptional preservation of Cambrain fossils including soft bodied animals such as worms
Charles Doolitte Walcott disvovered the Burgess Shale fossil b
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Hallucigenia
1991
Better presevered fossils of Hallucigenia from Chila were interpreted by Lars Ramskold and Hou Xianguang as walking on soft feet with the spines protecting the organism from predators swimming above
Now viewed as an onychophoran
Modern members of th
Better presevered fossils of Hallucigenia from Chila were interpreted by Lars Ramskold and Hou Xianguang as walking on soft feet with the spines protecting the organism from predators swimming above
Now viewed as an onychophoran
Modern members of th
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Charles Darwin
First scientist to work out that all living species were related to each other
Suggest the use of phylogenetic tree diagrams to show evolutionary relationships between organisms
Closely related species sharing recent common ancestors are on adjacent branc
Suggest the use of phylogenetic tree diagrams to show evolutionary relationships between organisms
Closely related species sharing recent common ancestors are on adjacent branc
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Benefits of Phylogenetic Classification
Organisams with the same taxon can be reasoned to be closely related. Fucus serratus (serrated wracj) and Fucus vesiculosus (bladder wrack) are closely related species of seaweed in the same genus
Aids communication between scientists - quicker to say ins
Aids communication between scientists - quicker to say ins
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Taxa are Discrete
No overlap
An organism belongs to one taxon or another
An organism belongs to one taxon or another
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Butterflies, Hover Flies and Beetles
Have an exoskeleton made of chitin and jointed legs, placing them in the phylum Arthropoda
3 body segments, wings and 3 pairs of legs, placing them in the insect class
3 body segments, wings and 3 pairs of legs, placing them in the insect class
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Beetles
Have their forewings as elytra (wing covers), placing them in the order Coleoptera
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Hover Flies
Only have one true pair of wings, placing them in the order Diptera
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Butterflies
Scaled wings placing them in the order Lepidoptera
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Animalia
Multicellular with no cell wall, heterotrophic eukaryotes
Nervous coordination
Animals are further divided into 2 groups
Chordates, with a backbone 5%
Non-chordates - invertebrates 95%
Nervous coordination
Animals are further divided into 2 groups
Chordates, with a backbone 5%
Non-chordates - invertebrates 95%
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Plantae
Multicellular, eukaryotic cells with cellulose cell walls, vacuoles containing sap and chloroplast containing photosynthetic pigments
Main phyla include th non flowering mosses and liverworts, ferns, conifers and the flowering plants
Main phyla include th non flowering mosses and liverworts, ferns, conifers and the flowering plants
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Fungi
Eukaryotic organisms made up of a mycelium which consists of threads called hyphae, some of which possess cross walls (septae)
No photosynthetic pigments - all heterotophs (either parasites or saprophytes), cell wall made of chitin
Reproduce by producing
No photosynthetic pigments - all heterotophs (either parasites or saprophytes), cell wall made of chitin
Reproduce by producing
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Proctoctista
Consists of small eukaryotic organisms with membrane bound organelles
Tissues show no differentiation
Protozoa and algae
Tissues show no differentiation
Protozoa and algae
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Prokaryotae
Unicellular organisms with no nucleus or membrane bound organelles
Possess a cell wall that is not made of cellulose or chitin
Bacteria and the blue gree algae are prokaryotes
Possess a cell wall that is not made of cellulose or chitin
Bacteria and the blue gree algae are prokaryotes
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The 3 Domain System of Classification
1977
Carl Woese et al. argued that all cellular life should be divided into 3 domains
Studied the sequences of the rRNA genes of bacteria and found fundamental biochemical differnces between eubacteria (true bacteria) and extremophile bacteria living in
Carl Woese et al. argued that all cellular life should be divided into 3 domains
Studied the sequences of the rRNA genes of bacteria and found fundamental biochemical differnces between eubacteria (true bacteria) and extremophile bacteria living in
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Archaebacteria Domain
Differences in their mechanism of DNA replication and the composition of their cell walls to bacterua in the eubacteria domain
The archaebacteria are actually more closely related to eukaryotes than to the eubacteria
Share a more recent common ancestor
The archaebacteria are actually more closely related to eukaryotes than to the eubacteria
Share a more recent common ancestor
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Common Ancestor
Share some common features
Similarities should indicate how closely related they arre
Pentadactyl limb in terrestrial vertebrates is an example of a homologous structure as it has the same basic structure in all terrestrial vertebrates
Differences and the
Similarities should indicate how closely related they arre
Pentadactyl limb in terrestrial vertebrates is an example of a homologous structure as it has the same basic structure in all terrestrial vertebrates
Differences and the
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Construction of Evolutionary Trees
Most similar organisms assumed to be the most closely related
There are organisms that share similarities becuase they occupy similar niches but are not closely related
Convergent evolution
Birds and insects have wings but are not closely related
Analogou
There are organisms that share similarities becuase they occupy similar niches but are not closely related
Convergent evolution
Birds and insects have wings but are not closely related
Analogou
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Pentadactyl Limbs of Tetrapods
Limbs of all tetrapods share the same basic structure of one large bone connecting to the body, followed by 2 smaller bones with usually 5 digits at the end
Good evidence for evolution from our common ancestor
A fish with 5 rays in its fins which crawled
Good evidence for evolution from our common ancestor
A fish with 5 rays in its fins which crawled
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DNA and Evolution
Electrophoresis and DNA hybridisation
Possible to quantify how related different species are and estimate when they most recently shared a common ancestor
Have shown that humans an chimpanzees share 97.6% of our DNA and that humans and rhesus monkeys have
Possible to quantify how related different species are and estimate when they most recently shared a common ancestor
Have shown that humans an chimpanzees share 97.6% of our DNA and that humans and rhesus monkeys have
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Biodiversity
A measure of the number of species and the number of individuals of each species in a given environment
Tend to increase over time in a previous barren habitat due to succession
Bare rock exposed after a volcanic eruption will initially be colonised by al
Tend to increase over time in a previous barren habitat due to succession
Bare rock exposed after a volcanic eruption will initially be colonised by al
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Ecosystems
Those with the greatest biodiversity are found near the equator
Tropical rain forests and coral reefs are being destroyed at an alarming rate
Human activities have increased extinction rates up to 50 times higher than at any time in the last 100000 years
Tropical rain forests and coral reefs are being destroyed at an alarming rate
Human activities have increased extinction rates up to 50 times higher than at any time in the last 100000 years
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Endangered Species
Habitat destruction aused by an increased use of land for agriculture, urban development, drainage of wetlands, forestry and mining
Competition from introduced species and environmental pollution and climate change now also threaten endangered species
Competition from introduced species and environmental pollution and climate change now also threaten endangered species
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Future Assets
Each species may be a future asset for humans as a source of food, useful chemicals such as future medicinal drugs from plant species and disease resistance genes
Human centred selfish arguement could be countered by the uniqueness of every species as eac
Human centred selfish arguement could be countered by the uniqueness of every species as eac
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Mass Extinction
Many argue we are currently experiencing a mass extinction
Previous mass extinctions and the resultant loss of biodiversity have been caused by environmental factors such as the meteor stroke - 65 million years ago that lead to the extinction of the dinos
Previous mass extinctions and the resultant loss of biodiversity have been caused by environmental factors such as the meteor stroke - 65 million years ago that lead to the extinction of the dinos
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Biodiversity Estimation
Calculated using an index of diversity such as Simpson's diversity index
Describes the biodiversity of motile organisms, such as aquatic invertebrates
Number of organisms of each species sampled and the number of species persent
Describes the biodiversity of motile organisms, such as aquatic invertebrates
Number of organisms of each species sampled and the number of species persent
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Biodiversity Formula
S = 1 -E n(n-1)
--------
N(N-1)
--------
N(N-1)
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N and n Biodiversity
N = The total number of organisms present
n = the population of each species
n = the population of each species
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Simpsion's Diversity Index
Varies from 0 to 1
The greater the value, the greater the biodiversity
Measures the probability that two individuals randomly sampled will belong to the same species
The greater the value, the greater the biodiversity
Measures the probability that two individuals randomly sampled will belong to the same species
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Genetic Biodiversity
Assessed by looking at the frequency of different alleles in the gene pool of a population
Higher the degree of polymorphism, the higher the genetic biodiversity
Higher the degree of polymorphism, the higher the genetic biodiversity
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Peas
There are 2 alleles that determine whether the plant is tall or dwarf
Low genetic biodiversity
Low genetic biodiversity
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Humans
3 Alleles that determine the ABO blood system
Ia, Ib and i
Polymorphic
High genetic biodiversity
Multiple alleles for the same gene and these cannot be explained by recent mutation alone
Ia, Ib and i
Polymorphic
High genetic biodiversity
Multiple alleles for the same gene and these cannot be explained by recent mutation alone
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Assessment of Biodiversity
1. The number of alleles at a particular locus
2. The proportion of the population that have a particular allele
2. The proportion of the population that have a particular allele
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Low Levels of Genetic Biodiversity
Population with low levels of genetic biodiversity in their gene pool are greater risk of extinctio than populations with high levels of genetic biodiversity as they lack the genetic 'toolkit' to be able to adpat to a changing environment
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DNA Fingerprinting and Sequencing
Used to idntify evolutionary relationships between species
Used to measure the genetic biodiveristy of a population
The squences at specific loci are usually analysed rather tthan sequencing an entire genome
DNA samples are collected and the base seqeunce
Used to measure the genetic biodiveristy of a population
The squences at specific loci are usually analysed rather tthan sequencing an entire genome
DNA samples are collected and the base seqeunce
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Galapagos Finches
Evolution by natural selection has led to the generation of biodiversity as adaptive radiation has led to the exploitation of niches
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Anatomical Adaptations of Galapagos Finches
The beaks of the Galapagos finches are adapted to eating different foods
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Physiological Adaptations of Galapagos Finches
The digestive system of seed eating finches would produce different enzymes to those that eat grubs
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Behavioural Adaptations of Woodpecker Finches
Uses caactus spines to dig out grubs from under the bark
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Other cards in this set
Card 2
Front
Taxa Largest to Smallest
Back
Kingdom
Phylum
Class
Order
Family
Genus
Species
Phylum
Class
Order
Family
Genus
Species
Card 3
Front
Rhyme of Taxa
Back
Card 4
Front
Human Taxa
Back
Card 5
Front
Incorrectly Classified
Back
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