Reproduction

SQA questions

Sperm and eggs WYSK• Sperm are the sex cells (g_______) produced

by m_____ in very l____ numbers but are much s_____ than eggs. Sperm have t_____ to s_____ and have limited f____ stores

• Eggs are the s__ c___ (gametes) produced by f______ in s_______ numbers than sperm. They are much _______ than sperm as they contain a large f_____ s_____

ametesales arge

maller ailswim ood

ex ell emales maller

largerood tore

Fertilisation WYSK• Male g_______ (s______) contains the m____

nucleus and the female gamete (___) contains the f______ n_________

• Each nucleus contains h____ the genetic i___________ needed for a new animal

• Fertilisation is the j_______ of the male nucleus and female nucleus which combines the g_______ i_________

ametes perm ale egg

emale ucleusalf

nformation

oining

enetic nformation

Internal/external WYSK

• In some fish, sperm are d_______ in the w_____ close to the e____.

• In m________ sperm are deposited inside the b_____ of the f_______.

• Internal fertilisation is needed in l_____ living animals so that there is f______ for the sperm to s____ to the egg.

eposited ater gg

ammalsody emale

andluid

wim

Testes/ovaries WYSK

• Sperm are produced in t_______.• Eggs are produced in o________ and are

released into the o________ where in m________ f___________ takes place

estes

variesviduct

ammals ertilisation

Sperm tubeurethratestis

penis

oviduct

ovary uterus

vagina

produces sperm C

oviduct

ovary produces eggs

oviduct

ovary uterus vagina

sperm tube

penis

testis

oviduct penis

produces eggs produces sperm

C Embryo develops here /implantation

nucleus

nucleus

water

amniotic

Development WYSK

• In fish, eggs are protected by a f_______ c_________ and the embryos obtain f_____ from the y____ s___.

• In a fish such as a t______ the young emerge from the eggs able to m________ themselves

• In mammals the fertilised egg passes down the o________ and becomes a________ to the wall of the u_______.

• The mammal embryo develops in the fluid of the a______ s___ and obtains its food from the m_________ blood circulation

• At birth the young of mammals are dependent on the adult for c___ and p_________

lexibleovering ood

olk acrout

aintain

viduct ttachedterus

mniotic acaternal

are rotection

Placenta CREDITThe placenta is a flat, disc like structure with

many f______ like p_________.These finger like projections help the placenta to

e________ substances between the mother and the embryo’s b______

G______ and oxygen d______ across the p_______ from the m______ blood to embryo’s blood

CO2 and w______ diffuse across the placenta from the e________ blood to the m________ blood

inger rojections

xchangelood

lucose iffuselacenta other’s

astesmbryo’s other’s

Number of eggs CREDITThe more p________ c_____ given by adults

then the less e____ or y______ need to be produced

Fish have l_____ parental care and therefore produce l____ of eggs and young

Mammals have lots of p_______ c____ and therefore produce few e_____ and y_____

arental are ggs oung

ess ots

arental are ggs oung

vagina

cervix

uterus

ovary

oviduct

fertilisation

division

ovulation

fertilisation

divides

implantation

fertilisation division implantation baby develops

1

2

3

4

Human Embryo

1

4

5

2

3

6amniotic sac

Development in Fish

Yolk sac3

flexible covering

Fish embryo12

Placenta mother’s blood vessels – A and B

embryo’s blood vessels – C and D