ANIMAL SURVIVAL REPRODUCTION Mr G Davidson. Reproduction All living things reproduce and produce offspring similar to themselves. If they did not reproduce,

ANIMAL SURVIVALANIMAL SURVIVAL

REPRODUCTIONREPRODUCTION

Mr G Davidson

ReproductionReproduction

All living things reproduce All living things reproduce and produce offspring similar and produce offspring similar to themselves.to themselves.

If they did not reproduce, If they did not reproduce, their numbers would their numbers would decrease and they would decrease and they would become extinct.become extinct.

Sexual ReproductionSexual Reproduction

Sexual reproduction involves Sexual reproduction involves the meeting of 2 sex cells the meeting of 2 sex cells called called GAMETESGAMETES..

The male gamete is called the The male gamete is called the spermsperm..

The female gamete is called The female gamete is called the the eggegg..

This meeting and joining is This meeting and joining is called called FERTILISATIONFERTILISATION..

FertilisationFertilisation

Fertilisation can either be INTERNAL or Fertilisation can either be INTERNAL or EXTERNAL.EXTERNAL.External fertilisation is usually found in External fertilisation is usually found in water based animals.water based animals.The gametes meet outside the body of the The gametes meet outside the body of the parents, e.g. trout.parents, e.g. trout.The eggs are released into the water and The eggs are released into the water and the sperm are released over the top of the sperm are released over the top of them.them.Large numbers of both are produced due Large numbers of both are produced due to the high chance of failure as well as the to the high chance of failure as well as the high mortality rate.high mortality rate.


Internal fertilisation is usually Internal fertilisation is usually found in terrestrial animals found in terrestrial animals (Land based).(Land based).It still requires the presence of a It still requires the presence of a fluid for the sperm to swim in.fluid for the sperm to swim in.The sperm fertilises the egg The sperm fertilises the egg inside the body of the female.inside the body of the female.

Human ReproductionHuman Reproduction

A male mammal has a special A male mammal has a special organ called a penis for placing organ called a penis for placing sperm into the female.sperm into the female.During copulation the penis is During copulation the penis is inserted into the female’s inserted into the female’s vagina.vagina.Sperm are released into the Sperm are released into the vagina.vagina.

Human Male Reproductive Human Male Reproductive SystemSystem

Testis Sperm duct

Penis

Scrotum

Foreskin

Prostate gland

Seminal vesicles

Urethra

Human Female Reproductive Human Female Reproductive SystemSystem

VaginaCervix

Uterus

Oviduct

Ovary

Labia


Fertilisation is when one sperm Fertilisation is when one sperm fuses with one egg.fuses with one egg.The sperm loses its tail and the The sperm loses its tail and the male nucleus joins the female male nucleus joins the female nucleus.nucleus.A membrane called the A membrane called the FERTILISATION MEMBRANE then FERTILISATION MEMBRANE then forms round the fertilised egg, forms round the fertilised egg, preventing other sperms from preventing other sperms from entering.entering.


In both types of fertilisation In both types of fertilisation there is an attraction between there is an attraction between the sperm and eggs.the sperm and eggs.

The sperm swim towards the egg The sperm swim towards the egg for fertilisation – in land animals for fertilisation – in land animals they swim in a fluid called they swim in a fluid called SEMEN.SEMEN.


Internal fertilisation is more Internal fertilisation is more efficient because the eggs are efficient because the eggs are protected inside the body of the protected inside the body of the mother.mother.

Fewer eggs are produced and Fewer eggs are produced and the gametes are closer together the gametes are closer together and therefore the chances of and therefore the chances of fertilisation are greater.fertilisation are greater.


After fertilisation, the fertilised After fertilisation, the fertilised egg called a ZYGOTE begins to egg called a ZYGOTE begins to divide and the first division divide and the first division results in 2 cells being formed.results in 2 cells being formed.

Further divisions increase the Further divisions increase the number to 4 then 8 and so on number to 4 then 8 and so on until a ball of many cells is until a ball of many cells is produced.produced.

Human DevelopmentHuman Development

Human females produce one egg Human females produce one egg per month in a process called per month in a process called OVULATION.OVULATION.The egg, released by the ovary, The egg, released by the ovary, passes into the fallopian tube passes into the fallopian tube (oviduct) where fertilisation may (oviduct) where fertilisation may occur.occur.The zygote divides and the ball of The zygote divides and the ball of cells produced becomes implanted cells produced becomes implanted into the wall of the uterus.into the wall of the uterus.


After the zygote has implanted into the After the zygote has implanted into the wall of the uterus it begins to grow and wall of the uterus it begins to grow and develop.develop.

A special structure called the PLACENTA A special structure called the PLACENTA develops, allowing the blood of the mother develops, allowing the blood of the mother and embryo to come very close without and embryo to come very close without mixing.mixing.

The embryo is attached to the placenta by The embryo is attached to the placenta by the UMBILICAL CORD.the UMBILICAL CORD.

The placenta allows the mother and embryo The placenta allows the mother and embryo to exchange essential materials.to exchange essential materials.



Trout DevelopmentTrout Development

Trout breed during the month of Trout breed during the month of November.November.After fertilisation occurs, the trout After fertilisation occurs, the trout eggs begin to develop.eggs begin to develop.Living organisms grow and develop Living organisms grow and develop at different rates.at different rates.During this time many changes may During this time many changes may occur before the organism becomes occur before the organism becomes sexually mature and capable of sexually mature and capable of reproduction.reproduction.

Trout Growth RateTrout Growth Rate

Age (years) Length (cm)

1 5

2 18

3 22

4 30

5 32

6 34

7 36

8 36


Trout Growth Rate

0510152025303540

1 2 3 4 5 6 7 8

Age (years)

Le

ng

ht

(cm

)


Between which years Between which years did the trout grow did the trout grow fastest?fastest?

At what age did it At what age did it reach full size?reach full size?

Suggest what size it Suggest what size it will be in 10 years.will be in 10 years.

Years 1 & 2

Year 7

36 cm

Survival ChancesSurvival Chances

Many gametes and young don’t Many gametes and young don’t survive reproduction.survive reproduction.

Only the fittest offspring survive Only the fittest offspring survive to produce more of the species.to produce more of the species.

Different groups of animals Different groups of animals produce different amounts of produce different amounts of eggs.eggs.

Survival ChancesSurvival Chances

Total No. Total No. of eggs of eggs produceproduce

dd

No. of No. of eggs eggs

fertilisedfertilised

No. of No. of eggs eggs

diseaseddiseased

No. of No. of zygotes zygotes eateneaten

No. of No. of young young eateneaten

RabbitRabbit 88 88 00 00 44

TroutTrout 30003000 20002000 200200 800800 850850

PheasaPheasantnt

1515 1212 22 22 33

HumanHuman 11 11 00 00 00

FrogFrog 10001000 750750 5050 200200 400400

Calculate the percentage survival rate of each animal.

Documents

ANIMAL SURVIVAL REPRODUCTION Mr G Davidson. Reproduction All living things reproduce and produce offspring similar to themselves. If they did not reproduce,