classification and evolution Flashcards
1
Q
What is classification?
A
The process by which living organisms are sorted into groups. The organisms within each group share similar features
2
Q
What are taxonomic groups?
A
Hierarchical groups of classification:
domain, kingdom, phylum, class,
order, family, genus, species
3
Q
Why do scientists classify organisms?
A
To identify species - by using a clearly defined system of classification, the species an organism belongs to can be easily identified • To predict characteristics - if several members in a group have a specific characteristic, it’s likely that so will another species in the group • To find evolutionary links - species in the same group probably share characteristic because they have evolved from a common ancestor
4
Q
What is a species?
A
The smallest and most specific taxonomic group. A species is defined as a group of organisms that are able to reproduce to produce fertile offspring.
5
Q
What is the classification of humans?
A
Domain: Eukarya Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Family: Homindae Genus: Homo Species: Sapiens
6
Q
What is binomial nomenclature?
A
The scientific naming of a species with a Latin name made of two parts - the first indicating the genus, and the second the species. No two species have the same generic (genus) and specific (species) name The name should be written underlined with only the first letter of the genus capital e.g. Felus catus
7
Q
What are the five kingdoms?
A
- Prokaryotae (bacteria)
- Protoctista (unicellular eukaryotes)
- Fungi (yeasts,moulds, mushrooms)
- Plantae (plants)
- Animalia (animals)
8
Q
What are the features of Prokaryotae?
A
• Unicellular • No nucleus or other membranebound organelles - a ring of ‘naked’ DNA - small ribosomes • No visible feeding mechanisms - nutrients are absorbed through the cell wall, or produces internally by photosynthesis • e.g. bacteria E.coli, Staphylococcus aureus
9
Q
What are the features of protoctista?
A
• (mainly) unicellular • A nucleus and other membranebound organelles • Some have chloroplasts • e.g. Paramecium, Amoeba • Some are sessile, but others moveably cilia, flagella, or amoeboid mechanisms • Nutrient are acquired by photosynthesis (autotrophic feeders), ingestion of other organisms (heterotrophic feeders), or both - some are parasitic
10
Q
What are the features of fungi?
A
• Unicellular or multicellular • A nucleus, other membrane-bound organelles, and chitin cell wall • No chloroplasts or chlorophyll • No mechanisms for locomotion • Most have a body or mycelium made of threads or hyphae • Nutrients are acquired by absorption - mainly from decaying material - they are prophetic feeders, and some are parasitic • Most store their food as glycogen
11
Q
What are the features of plantae?
A
• Multicellular • A nucleus and other membranebound organelles including chloroplasts, and cellulose cell wall • All contain chlorophyll • Most don’t move, although gametes of some plants move using cilia or flagella • Nutrient acquired by photosynthesis (autotrophic feeders) • Store food as starch
12
Q
What are the features animalia?
A
• Multicellular • A nucleus and other membranebound organelles (no cell walls) • No chloroplasts • Move with the aid of cilia, flagella, or contractive proteins, sometimes in the form of muscular organs • Nutrients are acquired by ingestion - they are heterotrophic feeders • Food stored as glycogen
13
Q
Why have there been changes to classification systems?
A
• Originally, classification systems were based on observable features • Through the study of genetics and other biological molecules, scientist can now study the evolutionary relationships between between organisms, and theses links can be used to classify organisms
14
Q
What happens when organisms evolve?
A
Their internal and external features change, as does their DNA, because the DNA determines the proteins made, which in turn determines the organisms characteristics
15
Q
What distinguishes the three domains?
A
The organisms in the different
domains contain a unique form of
rRNA and different ribosomes
16
Q
Describe the characteristics of the 3 domains
A
Eukarya • 80s ribosomes • RNA polymerase contains 12 proteins Archaea • 70s ribosomes • RNA polymerase of different organisms contains between 8 and 10 proteins and is very similar to eukaryotic ribosome Bacteria • 70s ribosomes • RNA polymerase contains 5 proteins
17
Q
Describe the three domain, six
kingdom classification system
A
18
Q
What is the difference between archaebacteria and
eubacteria?
A
Both are single-celled prokaryotes, but they have different chemical makeups • Eubacteria contain peptidoglycan in their cell walls whereas Archaebacteria do not
19
Q
Describe archaebacteria
A
• aka ancient bacteria • Can live in extreme environments e.g. thermal vents, anaerobic conditions, and highly acidic environments • e.g. methanogens live in anaerobic environments such as sewage treatment plants and make methane
20
Q
Describe eubacteria
A
- aka true bacteria
- Most bacteria
- Found in all environments
21
Q
What is phylogeny?
A
The evolutionary relationships between organisms • Reveals which group a particular organism is related to, and how closely related these organisms are
22
Q
What is a phylogenetic tree?
A
• aka evolutionary tree • Diagram used to represent the evolutionary relationships between organisms • Show that different species have evolved from a common ancestor • Earliest species found at the base of the tree, and the most recent species found at the tips of the branches
23
Q
What are the advantages of phylogenetic classification?
A
• Can be done without reference to Linnaean classification • Produces a continuous tree, whereas classification requires discrete taxonomical groups. Scientists are not forced to put organisms into a specific group that they don’t fit • Hierarchal nature Linnaean classification can be misleading as it implies different group within the same rank are equivalent
24
Q
What is evolution?
A
The theory that describes the way in
which organisms evolve, or change,
over many many years as a result of
natural selection
25
Q
Who was James Hutton?
A
• Scottish geologist who proposed the concept of uniformitarianism • The idea that in the past, the earth was shaped by forces that still exist today e.g. sedimentation in rivers, wind erosion, and deposition of ash and lava • Prompted Darwin to think of evolution as a slow process
26
Q
Who was Charles Lyell?
A
• Scottish geologist who popularised the principle of uniformitarianism • Wrote ‘Principles of Geology’ which Darwin read • Suggested the fossils were evidence of animals that had lived millions of years ago
27
Q
What was Darwin’s observation
of finches on the Galapagos
Islands?
A
• Noticed that different islands had different finches that were similar but had different beaks and claws suited to the food available on the island • The best suited finches would have more offspring, passing on its characteristic • Over time the finch population on that island would all share this characteristic
28
Q
Who was Alfred Wallace?
A
• Was working on his own theory of evolution in Borneo at the same time as Darwin • Sent his ideas to Darwin for peer review in 1858 • In 1859, Darwin independently published ‘On the Origin of Species’, and named the theory that he and Wallace had presented as ‘the theory of evolution by natural selection’
29
Q
What is the evidence of evolution?
A
• Palaeontology - the study of fossils and the fossil record • Comparative anatomy - the study of similarities and differences between organisms’ anatomy • Comparative biochemistry - similarities and differences between the chemical makeup of organisms
30
Q
What are fossils?
A
The remains or impression of a prehistoric pant or animal preserved in rock • Over long periods of time, sediment is deposited o the earth to form layers (strata) of rock • Different layers correspond to different geological eras, the most recent layer being found on top
31
Q
What evidence does the fossil
record provide?
A
Simple life forms evolve over a long time period into more complex ones • Fossils of simplest organisms e.g. bacteria are found in oldest rock • Fossils of more complex organisms e.g. vertebrates are found in more recent rocks Animals require plants to survive • Sequence in which the organisms are found matches their ecological links to each other • Plant fossils appear before animal fossils • By studying similarities in the anatomy of fossil organisms, scientists can show how closely related organisms have evolved from the same ancestor • Fossils allow relationships between extinct and living (extant) organisms to be investigated
33
Q
What are homologous structures (comparative
anatomy)?
A
A structure which appears superficially different (and may perform different functions) , but has the same underlying structure • e.g. the pentadactyl limb of vertebrates • An explanation is that all vertebrates have evolved from a common ancestor, therefore vertebrate limbs have all evolved from the same structure
