4.3 Classification and Evolution Flashcards
(126 cards)
1
Q
What is the binomial system?
A
A system that uses the genus name and the species name to avoid confusion when naming organisms.
2
Q
Define classification.
A
The process of placing living things into groups.
3
Q
Why do we group organisms?
A
- For our convenience
- To make the study of living things more manageable
- To make it easier to identify organisms
- To help us see the relationships between species.
4
Q
Who devised the classification system we use today to group living things?
A
Carl Linnaeus
5
Q
How did Carl Linnaeus put living things into categories?
A
Linnaeus organised living things into groups according to their visible features. He created a hierarchy of ranked categories. His original classification contained five levels: Kingdom, class, order, genus and species.
6
Q
Who changes Carl Linnaeus classification system and how was it changed?
A
Carl Woese Changed the system because he didn’t like how all bacteria was grouped together.
He introduced 3 domain above the kingdoms: Archaea, Eubacteria and Eukaryote. He also made the kingdoms 6 kingdoms: animal, plant, fungi, proctista, bacteria(eubacteria) and archaea (archaebacteria)
7
Q
What is a taxonomic levels?
A
A hierarchy of ranked categories.
8
Q
What taxonomic levels does the current classification system include, in order of hierarchy?
A
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
9
Q
What rhyme can you use to remember the taxonomic levels in the current classification system?
A
Kings and Princes Can Often Find Grass Snakes
(don’t forget Domain)
10
Q
What is a domain?
A
The highest taxonomic rank which includes: Archaea, Eubacteria and Eukaryote.
11
Q
What is a kingdom?
A
The second highest taxonomic level, ???????
12
Q
What is the taxonomic level, phylum?
A
A major subdivision of the kingdom. A phylum containing all the groups or organisms that have the same body plan, e.g. possession of a backbone.
13
Q
What is the taxonomic level, class?
A
A group of organisms that all possess the same general traits, e.g. the same number of legs.
14
Q
What is the taxonomic level, Order?
A
A subversion of the class using additional information about the organism, e.g. the class mammal is divided into meat-eating animals and vegetation-eating animals.
15
Q
What is the taxonomic level, family?
A
A group closely related genera, e.g. within the order Carnivora we might recognise the ‘dog’ family and ‘cat’ family.
16
Q
What is the taxonomic level, genus?
A
A group of closely related species.
17
Q
What is the taxonomic level, species?
A
The basic unit of classification. All members of the species show some variations, but are essentially the same.
18
Q
Why is it quite easy to place a species into it’s domain, kingdom or phylum?
A
At the higher levels of the ranked system, the differences between the organisms are very great.
19
Q
Why is it more complicated to place a species in a class compared to placing it in a domain or kingdom?
A
The differences between the classes in one phylum may not be very great. A longer description of the species may be needed.
20
Q
What does bionomial mean?
A
‘Two names’.
21
Q
What two names are used in the binomial system?
A
- Genus name
- Species name
22
Q
How must you write the names in the binomial system?
A
- The binomial system is in Latin.
- The genus name always has a capital letter and the species name has a lower-case one.
- The is typed in in italics or written underlined.
23
Q
Who devised the binomial system?
A
Carl Linnaeus.
24
Q
Why do we use the binomial system to name animals?
A
Before the binomial system, species were identified by a common name, or a long and detailed description sometimes in Latin too. Using a common name didn’t work because:
- The same organism may have had different common names in different parts of a country.
- Different common names used in different countries.
- Translation of languages or dialects may give different names.
- The same common names may be used for different species in different parts of the world.
25
Why is Latin used for the binomial system?
Latin is a **universal language** so in whatever country, the name is the same.
26
When classifying organisms, why is it important to study each specimen in detail?
There may be very small differences between similar species.
27
Why is a spider not an insect?
A spider does not have six legs, two pairs of wings and three body sections.
28
What is meant by the binomial system for naming organisms?
The use of scientific names for the genus and species.
29
Why is a standard way of naming organisms useful?
To avoid confusion, when different organisms may be given the same common name, or the same organism may be given different common names in different areas. To overcome language differences.
30
What is the biological definition of a species?
A group of organisms that can **freely interbreed** to produce **fertile offspring**
31
What group of organisms does the biological definition for a species not work for?
It does not work for organisms that reproduce asexually, as it is very hard to apply to organisms that are known as fossils.
32
What is the phylogenetic definition of a species?
A group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics.
Being so similar, the members in a species occupy the same niche in an ecosystem.
33
In early classification systems, what were groups based on? What this system good?
**Appearance and anatomy.**
For many cases, this provided enough information to allow accurate classification. However, it is easy to make mistakes.
34
What did Aristotle classify all living things into?
**Either plant or animal.**
He then **subdivided** the animals into **three groups**- those that:
* live and move in water
* live and move on land
* move through the air
35
In the 17th centaury, what happened which meant organisms can be classified more accurately?
By the 17th centaury, scientists had **microscopes** help.
36
What are 7 points that make-up the kingdom prokaryotes (Eubacteria & Archaebacteria)?
* Have **no nucleus**.
* Have **a loop of DNA** that is not arranged in linear chromosomes.
* Have **naked DNA**.
* Have **no membrane bound organelles**.
* Have **smaller ribosomes** than other groups.
* Have **smaller cells** than eukaryotes.
* May be free living/ **parasitic**.
37
What are 6 points that make-up the kingdom protoctista?
* Are **eukaryotic**.
* Mostly **single-celled.**
* Show a **wide variety of forms**.
* Show a **variety of plant-like and animal-like features**.
* Are mostly **free-living**.
* Have **autotrophic and heterotrophic nutrition**.
38
What is autotrophic nutrition?
A process where the organisms produces it's food via **photosynthesis**.
39
What is heterotrophic nutrition?
Heterotrophic nutrition is a mode of nutrition in which organisms **depend upon other organisms for food to survive**. They can't make their own food.
They digest larger molecules to form smaller molecules for absorption.
40
What are 5 points that make-up the kingdom fungi?
* Are **eukaryotic**.
* Can exist as **single cells** or they have **mycelium that consists of hyphae**.
* Have **walls** made up of **chitin**.
* Have a **cytoplasm that is multinucleate**.
* Are mostly **free-living and saprophytic**.
41
What are 5 points that make-up the kingdom plantae?
* Are **eukaryotic**.
* Are **multicellular**.
* Have cells **surrounded by cellulose cell wall**.
* Are **autotrophic**.
* Contain **chlorophyll**.
42
What are 4 points that make-up the kingdom Animalia?
* Are **eukaryotic**.
* Are **multicellular**.
* **Heterotrophic.**
* Are usually **able to move around**.
43
what does saprophytic mean?
A microorganism that lives on dead or decaying matter.
44
What is phylogeny?
The study of the evolutionary relationships between organisms.
45
What is artificial classification?
A type of sorting which:
* Is based on only a few characteristics.
* Does not only reflect any evolutionary relationships.
* Provides limited information.
* Is stable.
46
If members of the same species are very similar, what do we regard them as?
Closely related.
47
What group are two closely related species put in?
A genus.
48
What group are two closely related genera's be put in?
A family.
49
What is natural classifiation?
Natural classification groups organisms together so that the whole living world can be organised in to a series of ranked groups- a heirarchy. Natural classification:
* uses many characteristics.
* Reflects evolutionary relationships.
* Provides a lot of useful information.
* May change with advancing knowledge.
50
Why is natural classification that reflects real relationships between groups could be very useful?
If we want to find out more about rare or endangered species, we would not want to risk harming the individuals left. However, if we know a very similar species to provide information that is also applicable to the endangered species. This may make convervation more successful.
51
What is an evolutionary tree?
A phylogenetic tree is a branching diagram or a tree showing the evolutionary relationships among various biological species.
The time at which two species started to evolve separately is a branch point on the tree. The common ansestor appears on the tree at the branch point.
52
What is a common ancestor?
Any two species living today had a common ancestor. Common ancestors do not live today.
53
What does phylogeny involve?
It involves studying how closely different species are related.
54
What is a common ancestor?
A common ancestor is **an ancestor** that is **shared by two** or more different **groups of organisms.** **More than one** modern day **species arose** from that common ancestor.
55
What is the difference between phylogeny and classification?
**Classification** is **putting** things into groups; **phylogeny** is the **study** of the evolutionary relationships **between** those **groups**.
56
Why do we study how closely we are to other organisms?
Understanding the behaviour and physiology of other organisms that are closely related to us can help us understand our own behaviour and physiology.
57
Define monophyletic.
‘Monophyletic’ means that all members of that group **arose from one common ancestor**.
58
What arguments could be used to justify the use of live animals in testing new drugs?
If a drug may have **adverse effects,** it can be **tested on closely related species** the results should be applicable to the target species, saving possible harm to the target species, which may be a rare or endangered species (or it may be humans).
59
Why was it necessary to expand the classification system from two to five groups?
Further research revealed organisms that did not fit within the two-kingdom approach – some single-celled organisms have features of both plant and animal; others, such as fungi, have features of neither plant nor animal.
60
Why is it difficult to classify organisms like fungi?
They have a **range of features** that do not fit standard classification systems, e.g. they remain ‘rooted’ in one place, but use heterotrophic nutrition.
61
Why was it wrong that Aristotle classified birds and insects into the same group?
Both have wings, but birds are vertebrates – members of the phylum chordata; insects have an exoskeleton and belong to the phylum arthropoda.
62
Why did microscopes lead to better classification?
Higher magnification and better resolution allowed **more detailed observation** of details inside cells.
63
What are the differences between fungi and plants?
Plants have **chloroplasts** and chlorophyll, they **photosynthesise**, use **autotrophic nutrition**, have cell walls made of **cellulose**.
Fungi have **no chlorophyll** and do **not photosynthesise**, use **heterotrophic nutrition**, have cell walls of **chitin**.
64
What is convergent evolution?
When **two unrelated species** could **adapt** in similar ways and therefore **look very similar**.
65
What can help determine how closely two species are related which is more scientifically accurate than observing physical features?
Biological molecules.
66
How can biological molecules help determine how closely two species are related?
Certain large biological molecules are **found in all living thing**, such as those involves with **respiration** and **protein synthesis**, which are **fundamental** to life. If we assume that the earliest things all had identical versions of these molecules, then the differences today are a result of evolution. Therefore, Two organisms closely related will have similar molecules as they have not evolved separately for long.
67
What two biological molecules can be used to determine how closely two organisms are to eachother?
Cytochrome c and DNA.
68
What is cytochrome c?
A **protein** used in the process of **respiration**. All living organisms that respire must have a cytochrome c.
69
How can cytochrome c be used to tell how closely two species are related?
Cytochrome c is not identical in each species, therefore, if we **compare the sequence of amino acids in samples** of cytochrome c from two different species, we can draw conclusions including:
* If the sequences are the same, the two species must be closely related.
* If the sequences are different, the two species are not so closely related.
* **The more differences found between the sequences, the less closely relates the two species are.**
70
What is DNA?
A **biological molecule** that's found in all living organisms, providing the **genetic code** to **produce proteins**.
71
What does DNA being ‘universal mean’?
The code is **universal** (same code for all organisms)- this means that that a particular sequence of DNA code for the s**ame sequence of amino acids** in a bacterium as in another organism.
72
How can comparing DNA from two organisms help decide how closely related two species are?
When comparing two strands of DNA, if there is **many differences**, they would have been **evolving separately for a long time** so many different **mutations** would have occurred- this would be **less closely related**.
The **more similar** the two strands are, the **more** **closely related** they are.
73
What is the most accurate way to determine how closely two specie are related?
**Compare DNA** strands from the two organisms.
74
Why did Carl Woese suggest a new classification system?
He added the 3 domains which is based on the fact that **Bacteria are fundamentally different from Archaea**.
75
List 5 structural differences between Bacteria and Archaea.
* A **different cell membrane structure**
* **Flagella** with a **different** internal structure
* **Different enzymes** for synthesising DNA
* No **proteins bound** to bacteria's genetic material
* **Different mechanisms** for **DNA** replication and for synthesising RNA.
76
What does natural selection mean?
This this explains how features of the environment apply a **selective force** of the reproduction of individuals in a population.
77
Who came up with the idea of natural selection?
Charles Darwin.
78
How did Darwin come up with the idea of natural selection?
Darwin went on a trip to the Galapagos islands where he noticed clear variation in the species of finches found on each island. He concluded, that they were all from the mainland and then had evolved to form many different species.
79
What can you use as evidence for evolution?
* Fossil evidence
* Biological molecules
80
How are fossils evidence for evolution?
Fossils clearly show a number of interesting facts:
* In the past, the world was inhibited by **species that were different** from those present today.
* **Old species have died out** and new species have arisen.
* The **new species** that have appeared are **often similar to the old ones found** in the same place.
81
How do biological molecules give evidence for evolution?
* Certain molecules are found throughout the living world. If one species gives rise to another, both are **likely to have the same biological molecules-** suggesting they're from one original ancestor.
* The more closely related two species are, the **more identical their biological molecules** will be.
* Evidence from molecules such as **chromosome c** and other proteins show a pattern of changes.
82
What will happen to individuals that have advantageous alleles?
The will be more likely to survive and reproduce.
83
What does the process of evolution include?
Evolution works by selecting individuals with particular adaptations to survive and reproduce. A adaptations are therefore passed from one generation to the next- overtime, more and more individuals will have that adaptive allele.
84
How does natural selection work?
* **Mutations** create alternative versions of an allele, creating **genetic variation**.
* Once variety exists, then the environment can ‘select’ the characteristics that will give an advantage- this is a **selection pressure**.
* Individuals with an advantageous allele will **survive and reproduce,** passing on this allele.
* The **next generation** will have a **higher proportion of individuals** with the **successful allele** becoming more adapted to their environment.
85
What must occur before evolution can take place?
Variation.
86
In what organisms is evolution most obvious in?
Those with **short life cycles**.
87
Where can we clearly see evolution going on today?
* Bacterial resistance.
* Insects becoming more resistant to insecticides.
88
How do insecticides cause insects to evolve?
Insecticides produce a very strong selection pressure, if the individual insect is susceptible, then it will die. If it has some from of resistance, then the individual may survive- this will allow some resistance to reproduce and pass on the advantageous allele.
89
Why is insects become resistant to pesticides a problem.
Insects surviving after having **insecticide** is harmful because it can then **accumulate in the food chain**. These insects may then be **eaten by predators**, meaning they will receive a **higher dose** of the insecticide and its very possible the insecticide can move all the way up the food chain. In this way **humans can receive quite a high dose** of insecticide.
90
What is the selection pressure on bacteria causing them to evolve so quick?
The overuse and abuse of antibiotics.
91
What is an example of a resistant bacteria?
**MRSA** also known as meticillin-ressitant *Staphylococcus aureus*.
92
What is the evolutionary arms race?
**Medical researchers are struggling to develop new and effective drugs**, because the bacterial populations are **rapidly** becoming **more resistant** to them.
93
What is meant by convergent evolution?
Where two unrelated species have similar features as a result of **evolving adaptations to the same environment**.
94
How does convergent evolution make classification by observable features more difficult?
If the features look the same, the different species **may appear more closely related than they are**; they may be placed in the **same taxonomic group by mistake**.
95
Why is it essential to use molecules such as DNA or cytochrome c when looking for evidence to be used in classification.
These molecules are universal – they appear almost everywhere throughout the living world. Therefore, all living things can be compared for similarities and differences.
96
Explain why molecules such as starch or the enzyme amylase are not used for classification?
These molecules are **not found in all living things** – therefore, they cannot be used to compare all organisms. Also, the structure of starch is dependent on the structure of glucose and is always the same.
97
Why did Woese feel that the differences that he observed in the RNA polymerase of different groups were so important?
The function of RNA polymerase is **fundamental to living processes**, such as protein synthesis. **Similarities and differences will reflect relationships between groups.**
98
Use Darwin's observations to explain why he believed that there was a ‘struggle to survive’ and why only some individuals would pass on their characteristics.
Darwin observed that there was variation between individuals. When there is a struggle to survive, the **best adapted will survive most easily**; these individuals will reproduce and pass on their characteristics.
99
Spencer coined the term ‘survival of the fittest’- how does this relate to Darwin's views?
Fittest means ‘best adapted to the environment’, and those which are best adapted survive to pass on their characteristics – so those characteristics survive.
100
Why are half of our genes the same as a species very different from us like a banana?
**Many of the processes of life require similar structures and similar enzymes in all living things**, so many cell organelles, membrane structure and protein structures are shared.
101
Why is the fossil record not complete?
**Not all fossils have been found**; fossils do not form easily – **there may be no fossils** of some organisms; **erosion** may have washed fossils away; **movement of the ground** caused by earthquakes may disrupt the record.
102
What sort of biological molecule (apart from DNA) is most suited to use as evidence by natural selection?
Proteins (**cytochrome c**), because they consist of a sequence of amino acids that is dictated by the DNA. The structure of a protein must remain capable of performing its function, so it is unlikely to be totally transformed through evolution.
103
How many eye colour be advantageous to a predator and a prey species?
Eye colour can be used as **camouflage** so they cannot see each other.
104
What factors may cause a struggle among members of a population?
* **Shortage of any commodity**, such as food, water, nest sites; presence of predators or disease.
* **Adverse environmental conditions**, such as too dry, too wet, too hot, too cold, etc.
105
Why does a resource only become a selective force when it is limited?
If the resource is unlimited, there will be no competition and no related struggle to survive.
106
Why does evolution occur in a shorter time in populations of microorganisms than in populations of mamals?
**Microorganisms have a short generation time**. Selection can occur in each generation; if there are many generations in a few days or weeks, then **evolution can occur much more quickly**.
107
Why does evolution tend to occur in short bursts?
Selection occurs **when the environment changes and the organisms are not well adapted** – through selection they become adapted to the environment. Selection (and so evolution) slows or stops when the organisms are well adapted to the environment, until the environment changes again.
108
What is continuous variation?
Variation where there are two extremes and a full range of values between them.
109
What is discontinuous variation?
Where there are distinct categories and nothing in between.
110
What is environmental variation?
Variation caused by response to environmental factors e.g. light intensity.
111
What is genetic variation?
Variation caused by processing a different set of alleles.
112
What is interspecific variation?
The differences between species?
113
What is intraspecific variation?
The variation between members of the same species.
114
Define variation.
Differences between individuals.
115
How many forms of variation are there?
2: continuous and discontinuous variation.
116
In terms of the mean in continuous variation, how are the values typically spread?
**Most individuals are close to the mean** and the numbers of individuals at the extremes are low.
117
How many genes usually regulate continuous variation?
**More than one gene** and can be influenced by the **environment** where the organism lives.
118
Give some examples of continuous variation?
* Height in humans
* length of leaves
* Length of a stalk of a toadstool
* number of flagella on a bacterium
119
How is data showing continuous variation displayed?
With a histogram.
120
What is discontinuous variation regulated by?
Discontinuous variation is usually **regulated by a single gene** and is not influenced by the environment in which it lives.
121
What are some examples of discontinuous variation?
* **Gender**- mammals are either male or female.
* Some bacteria have **flagella and some do not.**
* **Human blood groups**- you are blood group A, B, AB or O
122
How is data showing discontinuous variation displayed?
Using a bar chart.
123
What are the causes of variation?
* Genetic
* Environmental
124
Why are humans are humans all different? (genetic variation)
Humans contain roughly 20,000 genes, many of which have more than one allele. Their chances of two individuals having exactly the same combinations of alleles is remote. So the combination of characteristics that each of us is unique.
125
what are some examples of environmental variation
* A person skin becoming tanned with exposure to the sun.
* A hawthorn tree being nibbled/ cut causing it to be more bushy.
* A pet being overfed so it becomes obese.
126
Where can we see the combine effects of environmental and genetic variation?
* Humans have become taller due to a better diet, however, you are unlikely to grow tall if your family is short.
* Some animals genes get turned on by certain changes in their environment, e.g. a gene controlling production of pigment in some rabbits is only active at lower temperatures, therefore become more brown in colder temperatures.
