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Flashcards in CLE1-4 Deck (44)
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1

Abiogenesis

is the natural process of life arising from non-living matter such as simple organic molecules
thought to occurred on earth 3.8-4.1 billion years ago

2

Last universal ancestor

it is believed that out of this multiplicity of protocells, only one line survived
lived during Archean eon (3.5bya or earlier)

3

Oxygen rich atmosphere

photosynthetic bacteria began releasing oxygen into the atmosphere
oxygen accumulation lead to ozone and blocked suns uv rays
unicellular organisms on land had a better chance of surviving on land

4

oxygen catastrophe

oxygen was toxic to most of the life on earth, resistant forms survived and thrived using oxygen to increase metabolism for more energy from the same amount of food

5

Cambrian explosion

was the relatively short evolutionary event beginning around 542 may in the Cambrian period during which most animal phyla appeared (as indicated by fossils record)

6

Timeline of life on earth

4.6bya earth forms
3.8bya abiogenesis
photosynthetic bacteria being o2 time
eukaryotes evolve
fish evolve
land plants
amphibians (marine animals move to land)
reptiles (eggs)
mass extinction(70 t 90 m)
dinosaurs evolve
mammals
birds
flowering plants
dinos and ammonites become extinct. birds mammals flowering plants survive

7

Law of superposition

using rock layers to relatively date fossils.
usually higher rock layers are younger than those below them
used to determine relative age of fossil

8

Radioactive dating

measuring radioactive traces of certain elements present in rock (absolute dating) to determine age of rock and any fossils contained in it

9

rocks contain radioactive

isotopes that decay at known rates (half lives) measuring amount of decay can provide info act rock age

10

Comparative anatomy

is the study of similarities and differences in structures of different species

11

Homologous structures

are structures that are similar in related organisms because they were inherited from a common ancestor.
may or may not have the same function in descendants
indicates evolution from common ancestor

12

The pentadactyl limb

homologous structure
most vertebrates have PL that has been modified for certain functions.
bird human lion have similarities in bone arrangements
each forelimb has humerus radius ulna carpals and phalanges

13

divergent evolution

the evolutionary process that has led to similar structures with different functions from a common ancestor

14

Convergent evolution

results in organisms that do not share a common ancestor but find themselves adapting to the environment in similar ways

15

Analogous structures

similar structures with similar functions not from a common ancestor

16

analogous structures example

wings of bats and birds look similar and have same function but they evolved independently of eachother

17

embryology

is the study of the development of embryos
structures present in early embryonic development are widely distributed among different animal groups while more distinguishing features appear later in embryonic development

suggest a shared common ancestor from high all vertebrate groups evolved from (show that they are based on the same structural pattern and could infer evolutionary change by observing change in development)

18

Comparative genomics

using molecular info to determine evolutionary relationships
eg comparing differences in haemoglobin molecules in primates

19

DNA hybridisation

a technique used to investigate evolutionary relatedness by measuring similarities between the DNA of different species

20

DNA hybridisation method

1) DNA from each species is isolated and separated into single strands
2)strands from each species are mixed to produce hybrid DNA(some bases will not match up non complementary base pairs)
3)Increasing amounts of heat is applied until the strands fully seperate

CLOSER MATCHES(MORE COMPLEMENTARY NUCLEOTIDES) REQUIRE MORE HEAT TO SEPERATE THE STRANDS

21

fossils

preserved remains and traces of once living organisms

22

Transitional fossils

intermediate fossils between major fossil groups (link them)
suggest that one group gave rise to another by evolutionary mechanisms

23

Fossil record

fossils preserved in rock of different ages provide a record or time scale for life on earth
evidence of past life and change in organisms over time

24

phylogeny

evolutionary history and relationships among groups of organisms

25

comparative genomics recently

comparison of DNA sequences that make up the genes using DNA hybridisation or automated gene sequences
SMALL DIFFERENCES INDICATES A RECEMT DIVERGENCE FORM A COMMON ANCESTOR

26

biological evolution

descent with modification from a common ancestor

27

microevolution

changes in allelic frequency of genes in a population of a species over generation (involves natural selection)

28

Macroevolution

the descent of different species from a common ancestor

29

natural selection

1. existing variation in population
2. differential selection (elective agents)
3. heredity- differential reproduction
4. pop as whole adapts to change

30

allopatric speciation def

macroevolution through natural selection(microevolution)