Mechanisms of Population Change

Question 1

4.1

what is adaptation

Answer 1

structure, behaviour, or physiological process that helps an organism survive and reproduce in certain environments

- variations that give a better chance at survival

Question 2

4.1

adaptation

why does it happen?

Answer 2

adaptations happen due to results gradual change of the population over time

Question 3

4.1

what is variation

Answer 3

variation is the visible / invisible differences between organisms of the same species.
can be an advantage or disadvantage or have no effect on the individual

can help and most likely be passed from survivor to survivor

Question 4

4.1

variation

can this become a adaptation?

Answer 4

no
if this varation is passed through the generations of survivors it could become something common. however not all varations become adaptation.

varations happen due to mutations in DNA

Question 5

4.1

what is a biological species

Answer 5

a biological species is a group of reproductively compatible populations

different populations can breed with other populations

Question 6

4.1

what is a mutation

Answer 6

changes in the genetic material of an organism

dna changes

Question 7

4.1

mutations

can they provide a selective advantage?

Answer 7

• mutations gives the organism a better chance at surviving = reproduce
• more common when the environment is changing, the mutation could be much favourable in the new environment

when dna mutates, a cell exhibits new characteristics and can be passed

Question 8

4.1

selective pressure

Answer 8

environmental conditions that select for certain characteristics of individuals and select against others

environmental factors that influence chances of survival

if you have a favoured adaptation of the environment you will most likely survive

Question 9

4.1

natural selection

Answer 9

characteristics of a population change because individuals with certain inherited traits survive and pass their traits to their offspring

occurs when there is variety/ diversity within a species

individuals of a population adapt to their environment by developing advantageous adpatations that will be passed on to their off spring

Question 10

4.2

Buffon

Answer 10

• challenged that life forms were unchanging
• in his book he noted that there were similarities between apes and humans and that they could have a common ancestor
• earth could be much more older than we expected

Question 11

4.2

Cuvier

Answer 11

• found that each layer of rock (stratum) is charaterized by a unique group of fossil species
• stated that the deeper(older) the layer, the more dissimilar the species were compared to modern ones
• new species were found, others disappeared=extinct
• natural disasters which he called “revolutions” were the reason for their extinction

Question 12

4.2

Lyell

Answer 12

• rejected the idea of revolutions
• geological proccess operated at the same rate as today and if they were to happen slowly and overtime than earth would be much older than 6000 years
• slow, subtle processes could happen over a long period of time and could result in important changes

Question 13

4.2

Lamarck

Answer 13

• interpreted current animals and animals back then were in a line of descent
• though species increased in complexity over time until they achieved perfection
• thought that characteristics that organisims acquired over their lifetime would be passed on to their offspring “inheritance of acquired traits”

Question 14

4.2

Darwin and Wallace

Answer 14

• accepted that populations changed as time passed
• individuals of the same species are in a constant struggle for survival
• individuals with more favourable variations are more likely to survive adn pass these variations on - survival isnt random its natural selection
• individuals with more favourable variation contribute more offspring to succeeding generations, the more these favourable inherited variations would be come more common, this isevolution

Question 15

4.2

Question 16

4.2

Darwin

Answer 16

• present forms of life have arisen by descent and modification of ancestral species
• mechanism of modification is natural selection
• theory of natural selection showed how populations of individual species became better adaped to their local environments over time

Question 17

4.2

Principle of Evolution

Answer 17

1. all life came from previous organisms through modification
2. natural selection was the mechanism for modification

• propsed that all life on earth descended from an unknown organism and as they spread out, they developed adaptations that best suited their environment for them to sruvive

Question 18

4.2

Evidence of Evolution

Answer 18

1. fossil records
2. biogeography
3. anatomy
4. molecular biology
5. genetics

Question 19

4.2

Fossil Evidence

Answer 19

• history of life recorded by remains from the past
• fossils found in young (recent) layers of rock are much more similar to fossils found in the deeper and older layers of rock
• fossils appear in chronoloogical order in rock layers
  ancestors of organismms would be found in older rocks which usually lie beneath the rock of recent species
• not all organisms appear in the fossil record at the same time

Question 20

4.2

transitional fossils

Answer 20

fossils that show intermediary links between groups of organisms

link the past to the present

Question 21

4.2

Biogeography

Answer 21

study of past and present geographical distribution of organisms
- the distribution of organisms is explainable by assuming that related forms evolved in one location and as they spread out to other accessible areas, they diversified

Question 22

4.2

Anatomy

Homologous - divergence

Answer 22

homologous structures have similar structural elements and origin but may have a different function
divergence : a single structure can change forms to meet at organisms needs in a new environment

Question 24

4.2

Anatomy

analogous

Answer 24

perform similar functions but they arent constructed the same way

same function, diff origin

Question 25

# **4.2** Embryological

Answer 25

similarities among embryos in related groups point to a common ancestor ## Footnote more closely related organisms will have more developmental stages in common

Question 26

# **4.2** Molecular

Answer 26

- dna - all living organisms use the same biochemical molecules including atp and many identical or nearly indentical enzymes and proteins - all consist of membranes filled with water, genetic material, proteins, lipids and carbohydrates

Question 27

# **4.2** Genetics

Answer 27

- dna is a hereditary material that determines the characteristics of the next gen - dna from closely related individuals have more of the same dna sequences and share more similarities - mutations cause changes in dna which lead to evolution

Question 28

# **4.3** biological species

Answer 28

group of organisms that can reproduce with one another in nature and produce fertile offspring

Question 29

# **4.3** speciation

Answer 29

- formation of a new species - two pathways

Question 30

# **4.3** speciation | transformation

Answer 30

a new species gradually develops as a result from mutation and adaptation to changing environtment **- the new species will replace the old one** | decreases diveristy

Question 31

# **4.3** speciation | divergence

Answer 31

on or more species arise from a parent species and both continue to exist | coexist with other species/at the same time ## Footnote increases biodiversity

Question 32

# **4.3** geographical barriers

Answer 32

= physical seperation ex: mountains, rivers - a barrier that puts organisms under different conditions must be maintained long enough for the population to become reproductively (genetically) incompatibe with the original population

Question 33

# **4.3** biological barriers

Answer 33

- physiological (how they work) seperation ex: behaviour - keep the same species reproductively isolated

Question 34

# **4.3** isolation

Answer 34

any seperation that leads organisms to survive under diff conditions

Question 35

# **4.3** adaptive radiation

Answer 35

the diversification of a common ancestral species into a variety of species which all adapted differently

Question 36

# **4.3** gradualsim

Answer 36

- developement of a new species is the produc of a many small chages which occur over a long period of time | many small changes iver a large period of time ## Footnote - a continuous process - not supported by fossil records because of transition

Question 37

# **4.3** punctuatued equilibarium | adaptive radiation

Answer 37

consist of long periods of the same with little to no change where periods interrupted by speciation | rapid speciation after mass extinction ## Footnote asignificant change occuring from a ancestrial species between longer periods of time