Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Year 12 Biology > Topic 11 > Flashcards

Topic 11 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

evolution

A

gradual adaptive change over geological time, in composition of populations from ancestral species to new species
-changes to DNA through mutations occur over long time period-introduce new alleles-changing genotypic frequency-changing phenotypic frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

microevolution

A

small scale changes within a gene pool of population of species over time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

macroevolution

A

large scale changes involving species over time- new species evolves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

relative dating technique

A
  • process depends on stratification- formation of sedimentary layers of rock
  • principle of superposition- older layer rocks are at bottom of strata sequence -overlain by younger layers
  • gives relative age
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

stratigraphy

A

relative age of fossil is determined by position of stratum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

principle of correlation

A
  • index fossils-fossils of species existed during limited periods of geological time and found in restricted depth of strata- used as guides to age of rocks in which they are preserved
  • presence of index fossil in different regions will be deemed to be same age
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

characteristics of index fossils

A

abundant, distinct, geographically widespread, found in many rock kinds, narrow in strata range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

absolute dating technique

A

radiometric dating is a technique in which actual age of fossils and rocks is expressed in years
-radioactive decay of some elements- used to establish absolute age of fossils and rocks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

potassium-argon dating

A
  • potassium 40 decays into argon 40

- has long half life- can be used to date rocks and fossils that are over 3 billion years old

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

carbon dating

A
  • fossils that contain organic matter, and are no older than 60,000 years old- can be dated using radioactive carbon dating
  • carbon-14 decomposes after death due to radioactive decay
  • longer since dead- lower ratio of carbon 14 to carbon 12
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

fossil record

A

-fossils provide evidence of organisms that once lived on this planet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

physical fossils

A
  • remains or whole of part of structures of organisms
  • organic material of these structures is replaced by mineral or organic matter has disappeared and organism simply exists as impression
  • decomposition happens quickly after death
  • decomposers and scavengers get rid of soft tissue’
  • weathering gets rid of bones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

fossilisation

A

process of preserving whole or part of organism, which lived in the past

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

trace fossils

A

-preserved evidence of activities of organism, such as footprints, tooth marks, tracks, burrows and coprolites- fossilised dung

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

biosignatures

A

physical or chemical sign preserved in minerals, rocks or sediments that can be inferred to be cellular or to have resulted from organisms metabolic activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

steps in fossil formation

A
  • mineralisation is required for fossilisation-unless in ice or sap
  • fossilisation occurs best in sap/ice then marine, then freshwater then terrestrial
  • hard parts of body fossilise best
  • organism dies and buried rapidly by volcanic ash, sediment, mud or silt- protects organism from scavengers and decay
  • rate of decay is slow in reduced oxygen/light and temperature
  • layers of material build up over top of organism- exerting pressure on remains
  • weight of overlying sediments compresses original sediment layer so that it become rock
  • mud becomes mudstone, sand becomes sandstone and volcanic ash becomes tuff
  • organism could also decompose slowly- leaves cavity called mould
  • mould becomes filled with minerals and hardens- forming cast of original organism
  • cast is 3D model of organism- original tissue replaced by carbon or minerals
  • repeated layers bury fossil- right temperature and pressure forms rock around fossil- strata forms
  • results in formation of different rock types with different fossils embedded in it
  • hard parts of organism are already hard and mineralised- fossilise well
  • imprints may also fossilise- due to sediments covering and filling imprint- later pressure resulting in rock formation
17
Q

why fossil record is incomplete

A

not all organisms die in areas that favour fossilisation- may decompose too quickly

  • scavengers may consume and destroy organisms- fossilisation wont occur
  • soft bodied organisms- not easily fossilised- cant mineralise
  • earth movements and lava can destroy fossils- make them inaccesible
18
Q

conclusions drawn from fossil record

A
  • fossilisation is a rare event
  • structure and arrangement of skeleton or bones- suggest size, shape, mode of locomotion and habitat
  • structure and arrangement of teeth- suggests diet and type of organism
  • evolution occurs from simple to more complex forms
  • different change in environments have influenced evolution in species over time
19
Q

transitional fossils

A

-if new species evolved from ancestral species- intermediate fossil evidence must exist that has characteristics of both ancestral and present forms of species.

20
Q

homology- similar structures

A
  • believed all vertebrates evolved from common ancestors
  • pentadactyl limb is found on most vertebrates has similar structure-homology
  • evolution occurs by modifying pre-exisiting structures
  • homologous structures are those similar in structure but can sometimes serve different function
21
Q

vestigial organs

A
  • functionless organs that were present and functional in ancestors
  • over millions of years- pelvis and femur have become very small- no longer fulfil locomotion function
  • presence of vestigial hind limbs in whales- supports evolution of whale from four limbed terrestrial mammal
22
Q

developmental biology

A
  • comparison of development of embryos- provides evolution evidence
  • pharyngeal arches present in all vertebrate embryos- develop into different adult structures
  • tail also found in embryos and adult vertebrates
  • suggests all vertebrates share a common ancestor

Year 12 Biology (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions