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Biology > Classification and Evolution > Flashcards

Classification and Evolution Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is classification?

A

Classification is the act of arranging organisms into groups based on their similarities and differences. This makes it easier for scientists to identify them and study them.

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2
Q

What is taxonomy?

A

Taxonomy is the study of classification and involves placing organisms into groups of taxonomic hierarchy

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3
Q

How does taxonomic hierarchy work?

A
  • there are eight levels
  • similar organisms are first sorted into one of the three domains
  • similar organisms are then sorted into slightly smaller groups called kingdoms
  • similar organisms are grouped into phylum and then into class and so on
  • as you move down there are more groups at each level but fewer organisms in each
  • the hierarchy ends with species and they contain only one type of organism
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4
Q

What are the five kingdoms?

A
  • Prokaryote
  • Protoctista
  • Fungi
  • Plantae
  • Animalia
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5
Q

What are the features and an example of an animal?

A

Insects, fish, mammals
- eukaryotic
- multicellular
- no cell wall
- heterotrophic

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6
Q

What are the features and an example of a plant?

A

Mosses, Ferns, and flowering plants
- Eukaryotic
- multicellular
- cell walls made of cellulose
- autotrophic
- contain chlorophyll
- can photosynthesize

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7
Q

What are the features and an example of a Fungi?

A

Molds, yeast, and mushrooms
- Eukaryotic
- chitin cell wall
- saprotrophic
- single-celled or multicellular

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8
Q

What are the features and an example of a protoctist?

A

Algae and Protozoa
- eukaryotic
- usually live in water
- single-celled or simple multicellular

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9
Q

What are the features and an example of a bacteria?

A

Bacteria
- Prokaryotic
- unicellular
- no nucleus
- less than 5 micrometers

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10
Q

What is the binomial system?

A

It is the nomenclature/naming system used for classification. All organisms are given one internationally accepted scientific name in Latin that has two parts.
The first part is the genus and has a capital letter. The second part is the species and has a lowercase letter. It is always written in italics or underlined.

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11
Q

What is phylogeny?

A

Phylogeny is the study of the evolutionary history of groups of organisms. Phylogeny tells us who’s related to whom and how closely related they are. You can view this on a phylogenic tree.

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12
Q

How can we tell how closely related two species are from a phylogenic tree?

A

The closer the branches/ the ones that have diverged away from each other most recently are the closest related species.

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13
Q

What is cladistics?

A

Cladistics is a system of taxonomy in which the organisms are classified into clades (groups) based on collective characteristics and having common ancestry

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14
Q

What did classification systems used to be based on and what was the problem with it?

A

They used to be based on observable features. But this method has problems as scientists don’t always agree on the relative importance of different features and groups based solely on physical features may not show how related organisms are.

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15
Q

How are classification systems based now?

A

They are now based on observable features along with other evidence.
Molecular evidence:
- how DNA is stored and its base sequence
- compare the sequence of amino acids in proteins
Embryonic evidence: the similarities in the early stages of an organism’s development
Anatomical evidence: the similarities in structure and function of different body parts
Behavioral evidence: the similarities in behavior and social organization of organisms

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16
Q

How have new technologies resulted in better classification systems?

A
  • New technologies can result in discoveries being made and the relationships between organisms being clarified
  • Scientists can share their discoveries in meetings and scientific journals. How organisms are classified is continually revised to take account of any new findings that scientists discover.
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17
Q

What is the three-domain system?

A

In 1990 the three-domain system was proposed. This new system has three domains- large superkingdoms that are above the kingdoms in the taxonomic hierarchy.
they are eukarya (nucleus), Archae (no nucleus), Bacteria (no nucleus)
Many scientists now agree that archaea and bacteria have evolved separately and that archaea are more closely related to eukarya.

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18
Q

What caused the proposal of a new three-domain system?

A
  • new molecular evidence
  • showed large differences between archaea and bacteria that were currently classified together as prokaryotae
  • enzyme RNA polymerase is different in bacteria and archaea.
  • Archaea, but not bacteria have similar histones to eukarya
  • the bonding of the lipids in the cell membrane of bacteria and archaea are different.
  • the development of flagella is different
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19
Q

What is variation between species?

A

The variation between different species is called interspecific varitation. For example the lightest and heaviest species of bird.

20
Q

What is variation within species?

A

Variation within a species is called intraspecific variation. And can be like robins with different length, wingspan, colour and beak size.

21
Q

What is continuous variaton?

A

Continuous variation is when the individuals in a population vary within a range- there is no distinct categories. e.g. height in humans

22
Q

What is discontinuous variation?

A

Discontinuous variation is when there are two or more distinct categories- each individual falls into only one of these categories, there are no intermediates. e.g blood group in humans

23
Q

What factors can cause variation?

A
  • genetic factors
  • environmental
  • both
24
Q

How do genetic factors cause variation?

A
  • different species have different genes
  • individuals of the same species have the same genes but different alleles
  • the genes and alleles make up its genotype
  • the differences in genotype make up variation and cause different characteristics
  • you inherit your genes from your parents
    e.g blood group is caused by genetic factors
25
Q

How do Environmental factors cause variation?

A
  • variation can also be caused by differences in the environment
  • characteristics controlled by environmental factors can change over an organism’s life.
  • Examples of variation caused only by environmental factors include accents and whether people have pierces ears
26
Q

How do both environmental and genetic factors cause variation?

A
  • genes, diet, and nutrients determine the height of a person
  • genes can decide whether an organism grows a flagellum but some will only start to grow them in certain environments
27
Q

How can you use the mean to investigate variation?

A
  • to investigate variation you usually take samples of a population
  • the mean is an average of the values collected in a sample. It can be used to tell if there is a variation between samples.
  • most samples will include values on either side of the mean, so you end up with a bell-shaped graph- this is called a normal distribution curve.
28
Q

What are adaptations and how do they help organisms?

A
  • being adapted to an environment means an organism has features that increase its chances of survival and reproduction, and also the chances of its offspring reproducing successfully.
  • these features are called adaptations and can be behavioral, physiological, and anatomical.
  • adaptations develop because of evolution by natural selection and in each generation the best-adapted individuals are more likely to survive and reproduce- passing their adaptations to their offspring. Others die before offspring.
29
Q

What are behavioral adaptations?

A

They are ways an organism acts that increase its chance of survival. for example, some possums play dead

30
Q

What are physiological adaptations?

A

They are processes inside an organism’s body that increase its chance of survival. For example, brown bears hibernate.

31
Q

What are Anatomical adaptations?

A

They are structural adaptations of an organism’s body that increase its chance of survival. For example, otters have a streamlined shape.

32
Q

Why do some different taxonomic groups have similar features?

A

They have similar features, even though they are not closely related as they have evolved in similar environments.

33
Q

What are marsupial mammals?

A

e.g. kangaroo
- have a short gestation period
- don’t develop a full placenta
- are born early in their development and climb into their mother’s pouch. Here they become attached to a teat and receive milk while they continue to develop.

34
Q

What are placental mammals?

A

e.g. humans
- have a longer gestation period
- develop a placenta during pregnancy which allows the exchange of nutrients and waste products between the fetus and the mother
- are born more fully developed

35
Q

Why do marsupial and placental moles share similar anatomic features?

A

Despite them not being closely related and evolving independently on different continents. They share similar anatomical features as they have both evolved to live in similar environments

36
Q

What are the three different groups of mammals?

A

marsupials, placental mammals, monotremes

37
Q

What adaptations do both marsupial and placental moles have?

A
  • small or nonexistent eyes (underground)
  • no external ears (streamlined)
  • scoop-shaped and powerful front paws (digging)
  • claws (digging)
  • tube-shaped body and cone-shaped head (easy to push through sand and soil)
38
Q

What four observations did Darwin make about the world around him?

A

1) Organisms produce more offspring than survive
2) There’s variation in the characteristics of members of the same species
3) Some of these characteristics can be passed on from one generation to the next
4) Individuals that are best adapted to their environment are more likely to survive

39
Q

What are the main points in Darwin’s theory of evolution?

A

1) Individuals within a population show variation in their phenotypes
2) Selection pressures create a struggle for survival
3) Individuals with better adaptations are more likely to survive and have reproductive success.
4) Over time, the proportion of the population possessing the advantageous adaptation increases.
5) Over generations this leads to evolution as favorable adaptations become more common in the population.

40
Q

How did Wallace contribute to the theory of evolution?

A
  • he independently came up with the idea of natural selection and wrote to Darwin about it
  • they published their papers on evolution together- although they didn’t always agree on some points.
  • he provided lots of evidence like warning colors to deter predators as an advantageous adaptation
  • however, people didn’t look at natural selection until Darwin talked about it in his book on the origin of species so- it is generally credited to him, not Wallace.
41
Q

How does fossil record evidence support the theory of evolution?

A

Fossils are the remains of organisms preserved in rocks. By arranging fossils in chronological order, gradual changes in organisms can be observed that provide evidence of evolution.

42
Q

How does DNA Evidence support the theory of evolution?

A
  • all organisms have evolved from shared common ancestors
  • closely related species diverged more recently
  • evolution is caused by gradual changes in the base sequence of an organism’s DNA
  • Organisms that have diverged away from each other more recently, should have more similar DNA, as less time has passed for changes in the DNA sequence to occur.
    (in eukaryotes scientists look at both nuclear DNA and mitochondrial DNA to see how closely related two organisms are)
43
Q

How does molecular DNA evidence support the theory of evolution?

A

In addition to DNA, the similarities in other molecules provide evidence. Scientists compare the sequence of amino acids in proteins and compare antibodies. Organisms that diverged away more recently have more similar molecules, as less time has passed for changes in proteins and other molecules to occur.

44
Q

What are pesticides and what is pesticide resistance?

A

Pesticides are chemicals that kill pests. Scientists have observed the evolution of pesticide resistance in many species of insects.
1) there is variation in a population of insects. Genetic mutations create alleles that make some insects naturally resistant to pesticides
2) if the population of insects is exposed to that pesticide only then the advantageous allele holders will survive
3) they will then reproduce and pass this allele to the next generation and consequently more individuals in the new generation will have the allele and so on…

45
Q

How does the evolution of pesticide resistance have implications for humans?

A
  • crop infestations are harder to control if they are pesticide resistant (takes farmers a while to find another, or find out which one is ineffective in the mixture used, by that time crops may all be dead) also a new pesticide may kills wanted insects so reduce biodiversity
  • the spread of disease could increase if carries become resistant
  • some could become resistant to all pesticides which puts pressure on the development of new ones which costs money and takes time.
46
Q

How does the evolution of drug resistance have implications for humans?

A
  • there is an observed antibiotic resistance in many species of bacteria
  • other pathogens have evolved resistance to specific drugs too. for example the protoctists for malaria
  • this makes it harder to treat infections with these drug-resistant microorganisms, especially if they are resistant to lots of drugs.
  • it can take doctors a while to figure out which drugs will get rid of the infection and therefore the patient at that time could get very ill and die.
  • some could become resistant to all drugs which puts pressure on the development of new ones which costs money and takes time.

Biology (26 decks)

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