Basic Evolution ATAR recap

Question 1

Define biological evolution

Answer 1

biological change over time

inherited change in a population over generations

evolution is a genetic change in a population over generations. populations evolve , individuals do not!

biological change in the characteristics of a population over time = evolution

variation + differential reproduction + heredity = evolution

Question 2

List all the different types of selection

Answer 2

natural selection
artificial selection (domestication)
sexual selection

stabilising selection
directional selection
disruptive selection

Question 3

define biological fitness

Answer 3

fitness = survival + reproductive success

Question 4

define a population

Answer 4

a group, within a species, of interbreeding individuals and their offspring, in the same geographic location

Question 5

darwins model of evolution by natural selection observation 1: (dont need to remember these)

Answer 5

observation 1: organisms have great potential fertility, which permits exponential growth of populations

Question 6

darwins model of evolution by natural selection observation 2: (dont need to remember these)

Answer 6

observation 2: natural populations normally do not increase exponentially, but remain fairly constant in size

Question 7

darwins model of evolution by natural selection observation 3: (dont need to remember these)

Answer 7

observation 3: natural resources are limited

Question 8

darwins model of evolution by natural selection inference 1: (dont need to remember these)

Answer 8

inference 1: a struggle for existence occurs among organisms in a population

Question 9

darwins model of evolution by natural selection observation 4: (dont need to remember these)

Answer 9

darwins model of evolution by natural selection observation 4: variation occurs among organisms within populations

Question 10

darwins model of evolution by natural selection observation 5: (dont need to remember these)

Answer 10

observation 5: variation is inheritable

Question 11

darwins model of evolution by natural selection inference 2: (dont need to remember these)

Answer 11

inference 2: varying organisms show differential survival and reproduction, favouring advantageous traits (= natural selection)

Question 12

darwins model of evolution by natural selection inference 3: (dont need to remember these)

Answer 12

inference 3: natural selection, acting over many generations, gradually produces new adaptations and new species.

Question 13

how is evolutionary change caused

Answer 13

evolutionary change is cause by differential survival and reproduction among organisms due to differing in hereditary traits.

Question 14

how do new traits arise

Answer 14

mutations in genes and chromosomes produce new variations which are passed on to subsequent generations

Question 15

how are new genetic combinations created

Answer 15

crossing over during meiosis
sexual reproduction

Question 16

gene definition

Answer 16

the unit of inheritance affecting the characteristics of a trait

Question 17

allele definition

Answer 17

one of two or more alternate expressions of a gene

Question 18

gene pool definition

Answer 18

all alleles in the eggs and sperm in a population

Question 19

genotype definition

Answer 19

the genetic makeup of an individual

Question 20

phenotype definition

Answer 20

the expression of the genotype and the environment

Question 21

adaptation definition

Answer 21

anatomical structure, physiological process, or behavioural trait that evolved by natural selection and improves an organism’s ability to survive and leave descendants.

Question 22

selection pressures biotic factors

Answer 22

competition
predation
disease

Question 23

selection pressures abiotic factors

Answer 23

climate
topography
habitat

Question 24

selection pressures three points to know (4)

Answer 24

• act on the phenotype
• act on all stages of the life cycle
• may act for many generations

Question 25

explain variation

Answer 25

variation occurs among organisms within a population

within a group there will be individuals at the extremes but most fall somewhere in between

Question 26

define stabilising selection and draw it on a graph

Answer 26

selects against extreme phenotypes

Question 27

define directional selection and draw it on a graph

Answer 27

phenotypic character shifts in one direction

Question 28

define disruptive selection and draw it on a graph

Answer 28

selects against average phenotypes

Question 29

define sexual selection

Answer 29

selection of traits that give an individual an advantage in attracting mates, even if these traits are neutral or harmful for survival

-> major morphological differences between the sexes within a species. (sexual dimorphism)

Question 30

define small-scale evolution

Answer 30

changes in gene frequency in a population from one generation to the next

Question 31

define large-scale evolution

Answer 31

the descent of different species from a common ancestor over many generations from the accumulation of multiple small allele frequency changes

Question 32

define the theory of gradualism

Answer 32

large differences in anatomical traits that characterise species originate through the accumulation of many small incremental changes over very long periods of time

Question 33

define the theory of punctuated equilibrium

Answer 33

long periods of evolutionary stasis (no change) followed by relatively short periods of rapid evolutionary change