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Flashcards in Evidence For Evolution Deck (16)
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1
Q

What is evolution

A

The cumulative change in the heritable characteristics of a population

2
Q

What are factors that provide evidence for evolution

A
Fossil record 
Homologous structures
Analogous structures 
Vestigial structures 
Direct observation 
Comparative DNA 
Selective breeding 
Natural selection
3
Q

How does fossil record provide evidence for evolution

A

Fossils document the existence of now-extinct species, which in turn helps us find the relation and similarities between past and present day species. It also physically helps us see how species evolved. They show a chronological sequence in which characteristics appear and develop in complexity in organisms.

4
Q

What are homologous structures

A

Homologous structures are parts of an organism’s body that are similar in structure to other species’ comparative parts. It is evidence of divergent evolution and shows an evolutionary relationship between organism that is a common ancestor.

Five-fingered pendactyl limb in vertebrates (humerus, ulna, radius, carpals, metacarpals, phalanges) these organisms in different forms of organisms have adapted to different modes of locomotion

5
Q

What are analogous structures

A

Structures of organisms that have the same function but do not have the same structural similarity. They do not have the same evolutionary path and do not show common ancestry. They are evidence of convergent evolution as different species have evolved to have similar features due to adaptation and environments.

Eg. Whale flipper and fish fin

6
Q

Vestigial structures?

A

An anatomical feature that no longer seems to have a purpose in the current form of an organism of the given species. It is an evidence of evolutionary relationship

Eg. Pelvic bone of whales are reduced and functionless but are evidence of their evolutionary relationship
The vestigial versions of a structure can be compared to the original version of the structure in other species in order to determine the homology of the structure

7
Q

how does direction observation support evidence for evolution

A

We can directly observe small scale evolution in organisms with a short life span, in turn providing evidence for evolution.

Eg. Antibiotic resistance where bacteria threat have grown resistant to antibiotics cannot be killed, the genes for resistances are passed on this increasing the population of resistant bacteria

8
Q

How is Comparative DNA evidence ??

A

DNA and the genetic code reflect the shared ancestry of life. DNA comparison can show how related species are

9
Q

What is the difference between a fact and a theory

A

A theory is a set of statements or principles that explains several phenomena at once. Most theories that are accepted by scientists have been repeatedly tested by experiments and can be used to make predictions about natural phenomena. A fact is any observation that has been repeatedly confirmed and accepted as true and has not yet been refuted.

10
Q

How does a hypothesis become a theory

A

Tests are made after a hypothesis is generated. From there, results can be corroborated or uncorroborated. Corroborated results goes on to be corroborated unquestionably thus a theory can be formed. Uncorroborated results are retested once a new hypothesis is formulated

11
Q

What is convergent and divergent evolution

A

Convergent evolution occurs when species with different ancestral origins evolve to develop similar features and adaptions

Divergent evolution occurs when species from a common ancestor evolve differently eg. Darwins finches as they had to adapt to different environments and different food sources

12
Q

What is a fossil and fossil record

A

Fossils are preserved remains, impressions or trace of an organism found usually in sediments, hardened as rocks from the remote past

Fossil record is the sum of all discovered and undiscovered fossils and their relative placement in rocks. It provides the dimension of time to the study of evolution as the fossils found can be dated.

13
Q

Types of fossils

A

Direct and indirect
Direct fossils are body fossils such as bones, teeth, shells and leaves
Indirect fossils are trace fossils such as footprints, tooth marks, tracks, feces, burrows

Organism can be fossilised by being trapped in a substance that protects it from destruction eg. Ice, amber, tar

14
Q

What are gaps in the fossil record due to

A

Special circumstances are required for fossilisation to occur eg. An organism who is buried quickly has better changes of being fossilised

Only hard parts of an organism are preserved

Fossils can be damaged so that only fragments remain to be discovered

15
Q

What are transitional fossils

And what type of rock is most likely to contain fossils

A

Transitional fossils all show the links between groups or species by exhibiting traits common to both ancestors and derived descendants

Sedimentary rock most likely contains fossils

16
Q

How are fossils formed

A

Fossilisation occurs when an organism dies and is quickly buried before it’s remains is destroyed by abiotic or biotic factors. Overtime, sediments and layers of rocks will build up and press down on the buried remains. Dissolved minerals transported by groundwaters in the sediments fill tiny spaces in the bones. The combination of pressure, chemical reactions and time eventually turns the sediments into rock and the bones into mineralized fossils. The fossils remain within the rock until uncovered through erosion of excavation