5.1.1

Question 1

what is sexual reproduction

key words, give an example

Answer 1

• process of forming a new organism from the* fusion *of the offspring’s parents’ gametes (sperm and egg)
• meiosis plays a big role
• humans and turtles examples

Question 2

what are organisms called when they have both sex cells in one and give examples

Answer 2

hermaphrodites

(flowering plants, earthworms)

Question 3

what is asexual reproduction and give example

Answer 3

• forming offspring from one parent
• mitosis
• offspring is a clone of parent : identical

hydra, amoeba

Question 4

wat r pros/cons for sexual reproduction

Answer 4

pro -
* high genetic variability
* adaptations r managed
* speeds up evolution

con
* energy costly
* mating takes time/finding mate
* usually sacrifices the fitness of one sex to the other (Amensalism)

Question 5

pros/cons of asexual reproduction

Answer 5

pros
* saves energy
* courtship aint issue/matin
* increase in fitness^

cons
* low genetic variability
* adaptation to selection pressures will be difficult if traits rnt favourable 4 speciees

Question 6

How sexual and asexual reproduction processes allow parents’ genetic information to be passed on to their offspring, and thus, ensuring the continuity of the species?

Answer 6

-genetic info is passed onto the next generation

-creates variation

-reporduction increases population size

Question 7

somatic vs non-somatic?

Answer 7

somatic - any cell other than reproductive

non-somatic : opposite

Question 8

define evolution

Answer 8

Evolution is the change in living organism’s genetic information, favourable characteristics and phenotypes over many generations.

Question 9

the stages of darwins theory of evolution? the six

Answer 9

1. genetic variation in population
2. majority of population have favourable traits
3. sudden change in environmental conditions
4. organisms w favourable characteristics will pass it on, while others with less favourable traits wil decline in numbers
5. organisms that r favourable wil reproduce successfully
6. new population full of favourable traits other than mutations

Question 10

what is an environmental change called

Answer 10

environmental agent

Question 11

what r three forms favourable characteristics can come in

Answer 11

physical, physiological and behavioural

Question 12

what are main sources of variation?

Answer 12

• adaptations that r inherited
• mutations
• independent assortment and random segregation during meiosis

Question 13

what are key examples of asexual reproduction and give example of how it formed

Answer 13

fungi - spores - zygomycota

bacteria - binary fission- coli

protists - budding- protozoa
protists-binary fission - amoeba

animals - parthenogenesis - bees

plants - frangmentation, runners, bulbs - mosses, strawberries, onions

Question 14

what r key examples of sexual reproduction and give examples

Answer 14

fungi-sexual-spores- mushroom

animals - internal/external fertilisation - humans

plants - self/cross pollination - sunflowers

Question 15

compare internal/external fertilisation

Answer 15

Internal – involves the fusion of male and female gametes within a parent’s body.
* terrestrial animals
* protects gametes from dehydration
* protects the fertilised eggs and developing young from immediate predation.

External - involves the fusion of male and female gametes outside a parent’s body.
* Tends to occur between aquatic animals

Question 16

what is the main goal for fertilisation generally

Answer 16

the gametes, each of which is a single haploid cell surrounded by a cell membrane, must meet and not dehydrate in the process

Question 17

what r the three things that intensify the chances of successful external fertilisation

Answer 17

• synchronisation of reproductive cycles
• mating behaviours
• release of gametes

This means that less time and energy is required of parents, but a larger number of gametes must be produced to ensure that some young survive.

Question 18

what is parthenogenesis and what is the plant and animals called that possess this

Answer 18

Process whereby an unfertilised egg develops into a functional offspring. This is a form of asexual reproduction in animals, mainly bees.

• in which a female can produce an embryo without fertilizing an egg with sperm.
• plants = apomixis
• animals = parthenogenesis

Question 19

what is pollination in simple words

Answer 19

Pollination is referred to as the process where the pollen is successfully transferred to the stigma of another plant.

Question 20

what r the male parts of the plant, the neutral parts, and femal eparts

Answer 20

female - stigma, style, ovary, the whole thing is carpel

male - anther, filament

neutral - sepal, petal, receptacle

Question 21

now describe the process of seual pollination

Answer 21

1. Once the pollen is on the stigma, it can grow a pollen tube
2. The pollen tube runs down the style of the plant and eventually into the ovary of the plant.
3. The ovary of the plant produces the ovules (the female gametes).
4. Fertilisation occurs in the ovule where the pollen can fertilise the ovule
5. A zygote is then formed through the fertilised ovule (the seed)
6. This fertilised ovule is called a seed which contains the zygote and will develop into an embryo

Question 22

what does the surronding space of the ovule become most commonly

Answer 22

a fruit

Question 23

what are the 2 main purposes for pollen grains produced by male

Answer 23

• pollen fertilisatises the two polar nuclei inside ovule which develops into endosperm
• it fertilises the ovum inside the ovule. the ovum is basically a seed which contains the zygote thatll grow

Question 24

differentiate between self/cross pollination

Answer 24

cross - Involves the transfer of pollen, produced by anther to the stigma of another plant

• Involves two plants
• The pollen grain essentially contain the male gametes of the plant. This can be taken to another plant’s stigma through wind, water and animal pollination.
• Utilises external agent (wind, animals, ocean)
• Results in an offspring that is genetically different to its parents

self pollination - Does not involve an external agent. The stigma can reshape itself to enclose the stamen. This means that the pollen can be easily transferred onto the stigma. less genetic variation

Question 25

what is vegetative propagation? give 3 examples

Answer 25

Vegetative propagation is a type of asexual reproduction that occurs in plants. It results in a parent producing a plant that is genetically identical. Examples include : * runners * bulbs * fragmentation

Question 26

what is fragmentation, give example

Answer 26

When the original organism separates a small part of itself. Example : occurs in starfish where a part of its body can be separated from its parent and the separated section can develop into a new starfish that is genetically identical to parent starfish via cell division

Question 27

what are runners, give an example

Answer 27

stems extending from the plant and along the soil. At certain points along the runners, nodes can develop which extends to the soil, resulting in the formation of new plant roots at another area of the soil whereby a new strawberry plant can grow.

Question 28

what are bulbs, give example

Answer 28

Bulbs are bud cells that are found underground. These buds can develop into new plants such as onions. When a new plant forms, the underground bulb provide nutrients to the plant for its survival.

Question 29

what is budding, how does it work and what does it occur in?

Answer 29

Budding in fungi, protists involves the parent cell developing a bud cell 1. Once a bud develops, it undergoes cell division while still being attached to the parent. the parent’s nucleus’ DNA then replicates and nucleus divides equally, but the cytoplasm divides unequally (hence bud is smaller than parent). 3. One copy of the DNA moves into the bud cell 4. The bud separates from its parent fungus when it grows to a sufficient size to be able support itself independently. 5. The now-separated bud undergoes further cell division to produce more bud cells. The result is yeast that is genetically identical to parent.

Question 30

what is spore production, give examples n is it a/sexual?

Answer 30

both sexual and asex -occurs asexualy in fungi -occurs sexually in fungi 1. spores are usually carried by the wind as they are light weight. 2. spores germinates to form genetically identical fungus when environmental conditions are favourable. 3. This typically involves the spores absorbing moisture and decaying organic matter 4. This allows the cytoplasm to expand and the fungus developing into a mycelium whereas new spores can be produced.

Question 31

what is binary fission how does it work and what does it occur in

Answer 31

occurs in bacteria, protists -1. The copying of genetic material in bacterial chromosomes of the parent cell occurs 2. Each chromosome moves to each side of the cell 3. the elongation of the cell and cytokinesis which is the splitting of the cell membrane and cytoplasm of the cell into two daughter cells takes place parent cell disappears at the end

Question 32

what are pros/cons of internal fertilisation

Answer 32

pros of internal - -protected, closed environment -embryo protected cons - -greater energy expenditure -less offspring produced at ONCE -mother becomes vulnerable in pregnancy

Question 33

pros/cons of external fertilisation

Answer 33

pros- -little energy -large numbers of offspring produced -offspring can be spread widely, reducing competition w parent orgnaims cons- -majority of gametes r unfertilised -offspring often not protected

Question 34

what r mammals and what r three characteristics that define mammals

Answer 34

A mammal is a vertebrate animal 1. mammary glands; producing milk/lactation 2. endothermic : generates heat from metabolic processes 3. hair/fur

Question 35

what r the three types of mammals

Answer 35

monotremes- egg laying mammals (platypus, echindas) A marsupial is a mammal that raises its newborn offspring inside an external pouch at the front or underside of their bodies. In contrast, a placental is a mammal that completes embryo development inside the mother, nourished by an organ called the placenta.