Chapter 8 - Evidence for evolution

Question 1

Species

Answer 1

A group of interbreeding organisms with similar characteristics capable of producing fertile offspring

Question 2

evolution

Answer 2

The process of cumulative, gradual, and heritable change in a population of organisms that occurs over many generations

Question 3

What is lamarks theory of transmutation of species

Answer 3

Organisms pass onto their offspring characteristics that they acquire during their life times. That is, individual behaviours during the lifetimes of organisms were the mechanism that drives adaptation

Question 4

phylogeny

Answer 4

evolutionary relationships that exist between species. Expressed in a tree like diagram

Question 5

How can the study of bio geography provide evidence of evolution

Answer 5

By looking at the pattern of distribution of plants and animals and fossils today

Question 6

Molecular homologies

Answer 6

The identification of shared bimolecular elements (generally genes) used to test the closeness of relationships between organisms. Can demonstrate common ancestry

Question 7

Homology

Answer 7

The existence of shared ancestry between a pair of structures or between genes

Question 8

Comparative genomics

Answer 8

Comparing the genome sequence of different species. The more similar in sequence the genes and genomes of two species are then more closely related those species are

Question 9

DNA hybridisation

Answer 9

A method used to analyse relatedness. Similarities in the base pairing of DNA strands are analysed to show evolutionary links between organisms. Can be unreliable when comparing closely related species

Question 10

Bioinformatics

Answer 10

Digital storage, retrieval, organisation and analysis of large volume of biological data

Question 11

Molecular phylogeny

Answer 11

The study of evolutionary relationships using comparative genomics

Question 12

steps of DNA hybridisation

Answer 12

DNA is extracted from two organisms, purified and cut into fragments. It is unwound and the hydrogen bonds joining the two sugar phosphate backbones is broken. The resulting single strands of DNA from the two organisms are mixed making hybrid DNA. Some lengths of DNA will not pair up because the bases do not match. The hybrid strands will bind together more strongly and be more resistant to separating when heated. Resistance is measured as % to work out relatedness

Question 13

Convergent evolution

Answer 13

A process whereby unrelated organisms evolve similar adaptations in response to similarity in their environments

Question 14

Mutation rate

Answer 14

The number of changes per gene copy in a population over period of time

Question 15

Comparative biochemistry

Answer 15

Analysis of the similarities and differences in the cellular chemistry of different species. Particularly includes study of proteins (especially enzymes) and the DNA that encodes them. Results enable relatedness between species to be measured

Question 16

Principle of superposition

Answer 16

States that the oldest rock layer is found in the deepest position, and each consecutive layer above it is a relatively younger. Indicates the relative ages of the rock layers and the fossils within them

Question 17

Stratum

Answer 17

The layers of rock in an area. Occur in order, with the oldest layers of the bottom

Question 18

Absolute dating

Answer 18

The process of determining the age of rocks and fossils they contain on the basis of physical or chemical properties of materials in the rock (Radioactive elements that occur naturally or organic matter)

Question 19

gradualism

Answer 19

Theoretical model of evolution the proposes that has been a steady, slow divergence of lineages, irrespective gaps in fossil records. Evolution only appears as a burst because of the absence of settlements containing fossils that document a transition. If a small section of fossil bearing sediments were absent this may account for missing millions of years in the fossil record. Gradualism states that if these fossils were still present it would show a divergent pattern that is gradual

Question 20

Punctuated equilibrium

Answer 20

Theory of evolution that proposes new organisms evolve quickly after a long period of no change rather than evolving by gradual change

Question 21

What are the two main types of fossil dating methods

Answer 21

Comparative dating and absolute dating

Question 22

What are the three main types of absolute stating

Answer 22

Radiometric dating, electrons spin resonance and luminescence

Question 23

Comparative dating

Answer 23

Process of determining the age of rocks that contain fossils relative to one another, allowing an estimation of the oldest to youngest without assigning actual age in years

Question 24

Radiometric dating

Answer 24

Uses the known rates of decay of naturally occurring radioactive isotopes present in rock or fossil to obtain an absolute date for its age

Question 25

Process of fossilisation

Answer 25

organism dies in a watery environment and is buried in mud and silt. Soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock.

Question 26

Comparative anatomy

Answer 26

study of similarities and differences in structure between different organisms. A larger number of similar features indicate some more recent common ancestor

Question 27

Morphological features

Answer 27

Structural features

Question 28

Homologous structure

Answer 28

Feature that has the same general structure but different functions and different organisms

Question 29

example of a homologous structure

Answer 29

All lizards have scaly skin, however scales can differ in colour, hardness and shape in response to conditions in the habitat that they occupy, serving varying functions of defence, temperature maintenance or camouflage

Question 30

Adaptive radiation

Answer 30

Process by which species is rapidly diversify into many taxes with differing adaptations. Triggered by factors such as reproductive barriers, changes in availability of resources, new challenges and new opportunities. Is a type of divergent evolution

Question 31

Vestigial structures

Answer 31

Biological structures that have lost the original function in the course of evolution. In ancestral organisms the structure served a purpose but in their descendants the structures become rudimentary. E.g. pelvic bone in a whale, human appendix

Question 32

Analogous structures

Answer 32

Features of organisms that have the same function but not the same structure e.g. the eyes of octopuses and vertebrates

Question 33

Speciation

Answer 33

The evolution of one or more new species from ancestral species. Divergent and convergent evolution

Question 34

Divergent evolution

Answer 34

Process where they related species evolve new traits over time spent living in different habitats, becoming increasingly different from the common ancestor and from one another giving rise to a new species

Question 35

convergent evolution

Answer 35

When unrelated organisms evolve similar adaptations in response to similarity in their environments

Question 36

What can cause divergent evolution

Answer 36

Populations may be separated by physical barriers such as mountains or rivers or other factors such as changes in reproductive timing