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Biology Year 10 > Evolution And Reproduction > Flashcards

Evolution And Reproduction Flashcards

1
Q

Evolution

A

A gradual change in range of organisms on earth. New species continually arise from species that already exist and other species become extinct

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2
Q

Natural selection

A

Change in allele frequency in response to a selection pressure. It’s the mechanism by which new species arise. Different forms species survive in different areas over time the species become increasingly different and may become different species . If the environment of the species change and the species is no longer adapted to survive in the new conditions it will become extinct.

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3
Q

How does natural selection occur

A

Mutation- provides the raw material for natural selection
Variation - biochemical , physiological , behavioural
Selection pressure - feature or change in the environment means not all individuals will survive (drought)
Reproduction - driving individuals pass alleles onto children
This is passed to the next geeneration and process repeats

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4
Q

Why does natural selection work

A

Struggle for existence due to overproduction of offspring. Form of species most suited to its environment will survive

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5
Q

Why is bActeria killed on explants

A

To prevent bacteria growing so the plant can be disease free and the bacteria and plant compete for food

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6
Q

What are two nutrients a plant needs to grow

A

Magnesium for chlorophyll production

Calcium for amino acids

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7
Q

How do plants reproduce asexuallay

A

Mitosis - genetically identical offspring has survival value in a stable environment

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8
Q

When is sexual reproduction advantageous

A

In a changing environment

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9
Q

What is a clone

A

Genetically identical to parent plant

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10
Q

How are plants traditionally cloned

A

By cutting . Cut stem is dipped into a hormone to encourage the cells of the stem to grow roots and develop into a new plant

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11
Q

Make sex cells plant

A

Pollen grain

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12
Q

Natural plant asexual reproduction

A

Plants grows a runner which breaks away from. The parent plant and grows into a new plant

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13
Q

Female plant sex cells

A

Ova

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14
Q

How are plant Sex cells transferred from the male to the female

A

By pollination, normally carried out either by wind or insects

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15
Q

What happens after pollination

A

Fertilisation takes place and the zygote develops into seed which becomes inclosed in a fruitb

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16
Q

Where are plant sex cells made

A

By meiosis . Pollen in anthers of the stamens. Ova in ovules in the ovaries

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17
Q

Why do plants want to disperse pollen

A

To fertilise other plants to avoid self pollination in order to maximise genetic variation

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18
Q

Why do Plants want to disperse seeds

A

To colonise areas in order to not compete for resources

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19
Q

Position of stamens

A

Insect - enclosed within flower so insect must make contact

Wind - exposed so wind can easily blow pollen away

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20
Q

Position of stigmas

A

Insect - enclosed within flower so insect must make contact

wind - exposed to catch pollen blowing in the wind

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21
Q

Type of stigma

A

Wind - feathery to catch pollen blowing in wind

Insect - sticky so pollen grains attach from insects

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22
Q

Size of petals

A

Insect - large to attract and brightly coloured

Wind - small

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23
Q

Nectaries

A

Only present in insect as a reward for insects

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24
Q

Pollen gRains

A

Insect - large sticky to stick to insects body’s

Wind - smaller smooth inflated grains to carry in wind

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25
How does plant fertilisation take place
Pollination transfers the pollen grain to the stigma. However the fertilisation to take place, the nucleus of the pollen grain must fuse with with the nucleus of the ovum which is inside an ovule in the ovary. To transfer the nucleus to the ovum the pollen grain grows a tube, that digests its way through the tissue of the style and into the ovary. It grows around to the opening in an ovule , the tip disolved and the pollen grain nucleus moves out of the tube and into the ovule where it fertilised the ovum nucleus and develops into a seed
26
What happens after fertilisation plants
The zygote develops into an embryonic plant with a small root (radicle) and shoot (plumule). The other contents of the ovule develops into cotyledons which will be a food store for the young plants when the seed germinates . The ovule wall becomes the seed coat and the ovary wall becomes the fruit coat
27
What is germination
Seed growth
28
What happens during germination
Food store used up providing nutrients for the radicle and plumule to grow .
29
Where does radicle grow
Down into soil to absorb water and mineral ions
30
Where does plumule grow
Upwards to the light to start the process of photosynthesis .
31
When is germination over
When the seedling is able to photosynthesis
32
What conditions are needed for germination
Seeds are dry to restrict metabolism and make seeds dormant when the seed germinates dormancy is broken and the food store is broken down by enzymes and respires aerobically. This needs Warm temperatures for efficient enzyme action Water for chemical reactions to take place in solution Oxygen for respiration
33
What are two things produced in the testes
Sperm and testosterone
34
Where are gametes produced in females
Ovaries
35
How are oviducts adapted
They have cilia
36
Where does fertilisation occur humans
Fallopian tubes
37
Where does the foetus grow and develop
Uterus
38
Where is liquid added to sperm
Prostate gland and seminal vesicle
39
2 adaptations of egg cell
Jelly layer that gardens after sperm enetery Lots of nutrition for baby to develop Haploid nucleus
40
What liquids are carried by uretha in men
Urine and semen
41
What is the ureter
Connects the kidneys and bladder
42
3 adaptations of sperm cell
Head to penetrate egg Streamlined to swim fast Haploid cell
43
Where are sperm stored
Epidydymis
44
What are 3 stages of human reproduction
``` 1. Preparation Generates gametes by meiosis Preparation for growth of embryo 2. Delivery of male gamete to remain 3. Fertilisation Growth and incubation of offspring cells divide by mitosis Delivery of offspring ```
45
Testes
Make sperm and testosterone
46
Epididymis
Large tube for storage of sperm
47
Vas deferens
Duct which carries sperm to penis
48
Seminal vesicles
Secretes alkaline fluid and nutrients
49
Prostrate gland
Adds more fluid and nutrients
50
Uretha
Pases semen
51
Ovary
Develops eggs . Secretes oestrogen and progesterone
52
Follicle
Each follicle contains and develops the egg and secretes progesterone and oestrogen
53
Fallopian tube
Moves eggs towards uterus by cilia
54
Uterus
Muscular organ with soft lining allows development of embryo and foetus
55
Cervix
Ring of muscle at lower end of uterus closes off uterus during pregnancy
56
Vagina
Receives sperm from erect pe is during intercouse
57
Zygote
Fertilised egg
58
Embryo
Zygote divides by mitosis into an embryo
59
What is a hormone
Small chemicals that travel in the bloodstream to give a message to other parts of the body
60
Why do animals develop secondary sexual characteristics
To signal that the animal is sexually mature
61
Primary sexual characteristics
Genetalia
62
Secondary sexual charcachtetistiss in boys is caused by
Testosterone
63
Secondary sexual characteristics girls caused by
Oestrogen
64
When do secondary sexual characteristics occur
Puberty
65
What is ovulation
Release of a mature egg caused by LH
66
What does FSH stand for and what does it cause
Follicle stimulating hormone | Causes follicle to grow and start the process of real easing the egg. Peaks before ovulation as does LH and oestrogen
67
What happens after ovulation
Progesterone increases to stop FSH being produced . If egg implants progesterone remains high to stop ovulation and periods . If egg does not implant progesterone levels decline
68
What is the function of the placenta
Allows foetus to obtain materials such as oxygen and nutrients from the mothers blood and allows foetus to get rid of waste products
69
What is the function of amniotic fluid
To protect foetus from bumps and jolts and regulate temperature
70
What does the umbilical chord transport
Antibodies to provide foetus with immunity
71
What nutrients are important for development of foetus bones
Vitamin d and calcium
72
What does a pregnant women need more energy
Has more mass used more energy to walk around Baby needs energy for growth and respiration
73
Why does baby need iron
To form haemoglobin . Red blood cells have haemoglobin made from iron that carries the oxygen the baby needs to respire
74
Who produces the placenta
The baby by mitosis
75
What is exchanged in the placenta
No blood Oxygen and glucose Diffused in the placenta and carries to the baby through the umbilical vein
76
Waste products foetus
Carbon dioxide | Urea
77
Adaptations of the placenta
Thin walls faster diffusion Good blood supply maintains concentration gradients Villi increase surface area for quicker diffusion
78
How does fertilisation occur humans
Sperm reaches ovum and nucleus enters the ovum fuses with ovum nucleus . Fertilisation membrane prevents any more sperm from enetering
79
What happens in development of zygote
Cell division by mitosis cells move around different shape structures are formed and cells specilize
80
Where does embryo implant
Zygote develops into embryo and is implanted in uterus lining
81
What does placenta secrete
Female hormones particularly progesterone to maintain pregnancy
82
Where does amniotic fluid come from
The Amnion that Incloses the developing foetus
83
How do bodies start adapting to reproduce
By fsh and LH released by the pituary gland Boys fsh stimulates sperm production and instructs testes to secrete testosterone Girls they control release of oestrogen from ovaries
84
What happens if egg is not fertilised
Uterus lining shed
85
When is egg relaesed
When follicle bursts open . This is ovulation
86
What happens to womb lining during ovulation
Repaired and thickend by oestrogen that also slows down fsh and stimulates secretion of LH. Peak of LH causes ovulation
87
What is left of follicle after ovulation
Corpus luteum
88
What causes growth of corpus luteum
LH
89
What does the corpus luteum make
Progesterone that completes devlopment of uterus lining for the egg to implant
90
If egg is fertilised
Corpus luteum keeps making progesterone later in pregnancy placenta takes over role of the corpus luteum
91
If egg is not fertilised
Corpus luteum breaks down stops oriducing progesterone and uterus lining is shed
92
What is a seeed
An embryo and a food store surrounded by a seed coat
93
What happens in germination when
Seed coats split and emergence of the plumule and radicle
94
What is seedling
Shoot grows towards light and ge root system spreads
95
What is flowering
The bud opens and petals unfurl revealing reproductive system
96
Independent variable
Something you change
97
Dependent variable
Something you keep the same
98
Filament
Holds up the anther
99
Sepal
Protects unopened flower
100
Ovule
Female sex cells
101
Ovary
Produces ovules
102
Stigma
Collects pollen grains
103
Style
Connects stigma to style
104
Stamen
Male - anther and filament
105
Carpel
Female - stigma , style and ovary
106
Why do people selectively breed crops
To produce strains that are Giving higher yields Resistant to certain diseases that would reduce the yields Resistant to certain insect pest damage that would reduce the yield Are hardier to survive harsher climates or be more productive for longer periods of the year Have a Better balance of nutrients in the crops e.g contain more of the types of amino acids needed by humans
107
Why do people selectively breed animals
To produce more meat , milk and eggs Produce more fur or better quality To produce more offspring To show increased resistance to diseases and parasites
108
How is tye process or selective breeding carried out
1. Variation in a population 2. Choose the organisms with desireable characteristics 3. Breed together 4. Choose offspring with desirable characteristics 5. Repeat This process is slow and imprecise
109
How has artificial insemination helped selective breeding
Bulls with desirable features are kept and semen is obtained from them diluted frozen and stored Farmers can buy quantities of this semen to inseminate their cows Semen from one prized bull can fertilise thousands of cows
110
How do you traditionally clone plants
Take a cutting and dip it in rooting powder , plant in compost and place under glass as this creates a warm environment to speed up growth and reduce water loss as they grow they form new cells by mitosis and develop into a group of genetically identical plants
111
How are plants cloned modernly
Micropropagation Explant (tip of stem and side shoot ) removed and placed in sn agar medium that contains nutrients and plant hormones to encourage growth Expands with shoots transferrrd to another culture medium containing a different balance of plant hormones to induce root formation When explants have grown roots they are transferred to greenhouses and transplanted into compost. The moist atmosphere reduces water loss from young plants
112
What are the advantages to micropropagation
Large number of genetically identical plants can be produced rapidly Species that are difficult to grow from seed or cuttings can be cloned this way Large number of plants can be stored easily Genetic modification can be introduced into thousands of plants quickly
113
How was dolly cloned
Body diploid cell of desirable sheep Donor unfertilised egg had the nucleus removed and an electric shock caused the membranes of the egg cell and body cell to fuse . This left a zygote which divided by mitosis into an embryo which was transferred into a foster mother that gave birth to a lamb genetically identical to the desirable sheep
114
What is another way to produce a desireable organism
Genetic modification that is fast and precise we can add or delete a gene animals can be genetically modified to produce human organs
115
What are the 6 groups for classification
Animals plants funghi protoctists bacteria viruse

Biology Year 10 (5 decks)

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