Chapter 10 - Changes In Biodiversity Over Time

Question 1

Charles Darwin and Alfred Wallace

1. Two conflicting views
2. Darwin’s voyage on the Beagle

Answer 1

1.
• each species was unchanging and were all specifically created
• species were mutable and could evolved to produce new species.

2. Diversity of bird species (finches) on the Galápagos Islands; various beak types.

Question 2

Time scales in evolution

1. Modern geological time scale divided into?
2. Modern theory of evolution
3. First … appeared?
   • members of the genus Homo
   • Homo sapiens
   • multicellular organism
   • animal on land
   • flowering plant
   • mammal

Answer 2

1. Eras and then into periods.
2. All living organisms share a common origin, dating back more than 4 billion years.
   3.
   • 2.8 MYA
   • 200,000 YA
   • 17 MYA
   • 600 MYA
   • 130 MYA
   • 160 MYA

Question 3

Relative age based on stratigraphy

1. Define stratigraphy
2. Define stratum
3. Lower or upper stratum older?

Answer 3

1. The study of the relative positions of layers of rock (strata), some of which contain fossils.
2. A layer of a series of layers of rock in the ground
3. Lowest stratum is the oldest.

Question 4

Absolute dating by radiometric methods

1. Radiometric dating methods are used to measure?
2. Half-life of atoms
3. Carbon-14 dating
4. Potassium-40 dating
5. Thermo luminescence
6. Electro-spin resonance

Answer 4

1. Estimate the age of igneous rocks (volcanic activity)
2. Half life = the time taken for half of the atoms in a sample to decay.
3. Measures the loss of isotope carbon-14, taken up by an organism when it was alive, within its fossilised remains.
4. Measures the decay of potassium-40 to argon-40 in volcanic rocks; good for old fossils, not new.
5. Emission of light from a mineral when heated - the older the objects the more light it emits.
6. Measures the microwave energy energy absorbed by samples previous heated or exposed to sunlight in the distant past.

Question 5

Evidence for biological changes

The concept of evolution is based on a variety of evidence including:

1. Palaeontology
2. Biogeography
3. Development biology
4. Structural morphology

Answer 5

1. The study of fossils.
2. The study of the distribution of species and ecosystems.
3. The study of the process by which organisms grow and develop.
4. The study of size, shape, form and structure of species.

Question 6

Palaeontology

1. Two types of fossils
2. What are biosignatures?

Answer 6

1.
• physical fossils = remains of all or part of the structure of an organism (bones, teeth, leaves).
• trace fossils = preserved evidence of the activities of organisms (footprints, tooth marks, tracks, burrows, fossilised dung)

2. Physical or chemical sign preserved in minerals, rocks or sediments linked to cellular life - corrosion pits in rocks.

Question 7

Palaeontology

1. How a fossil forms?
2. Conditions that enhance fossilisation?

*often only hard parts (teeth, bones, shells)

Answer 7

1.
• rapid burial of the organism is required.
• after the burial, the bones are subjected to pressure. Minerals in the surrounding sediments move into the bones and replace the minerals in them.
• then erosion of the sediment exposes the fossils on the surface.

2. • Hard parts are buried or entombed in sediments (e.g. silt, sand, mud, ash), formation of coal, frozen in ice, trapped in amber (resin from certain trees), in lava flows or quicksand.
   • buried in conditions that are oxygen-depleted or oxygen-free. Yeah

Question 8

Define fossils

Answer 8

Fossils are the remains of long-dead organisms that have escaped decay and have become part of the earth’s crust.

Question 9

Biogeography

Support concepts such as Gondwana (southern super-continent) and continental drift (movement of crystal plates)

1. Gondwana

Answer 9

1. Existed in the Southern Hemisphere more than 135 MYA. It included Africa, Madagascar, India, Australia, New Zealand, South America and Antarctica.

Question 10

Developmental biology / comparative embryology

Answer 10

Because they share a common ancestry, all vertebrate embryos display some common features at some point during their development - tail, notochord, hollow nerve cord, pharyngeal arches

Question 11

Structural morphology

Define

1. Comparative anatomy
2. Homologous features
3. Analogous features
4. Vestigial features

*diagrams pg45

Answer 11

1. Striking resemblance in structure (e.g. humans and chimpanzees).
2. Fundamental similarities of structure, but different functions. E.g. tetrapods’ limbs have the same basic structure.
3. Anatomical features that serve the same function but do not the same structural similarity. E.g. wings in birds as butterflies.
4. Structure with no apparent function that resemble structures found in other organisms. E.g. appendix.

Question 12

Patterns of biological change

1. Divergent evolution 
• Define
• Type of features that support
2. Adaptive radiation
• Define
3. Convergent evolution
• Define
• Type of features that support
4. Mass extinction 
• Define

Answer 12

1. Change from a common ancestral species increases as time passed leading to a speciation event - evolution of two new species.
   • homologous features
2. Evolution of varieties of a species, each adapted for life in a different niche and each Orville’s over time from a single ancestral species - a special case of divergent evolution. E.g. Darwin’s finches.
3. development of similar features separately in unrelated groups of organisms. Natural selection may lead to them evolving one or more similar features.
   • analogous features
4. The evolutionary process whereby abnormally high numbers of species and groups of species die but over a relatively short time.