10 Reproduction Flashcards
(53 cards)
Define asexual reproduction
process resulting in the production of genetically identical offspring from one parent
Advantages of asexual reproduction (3)
Only one parent required
large number of organisms can be produced in a short time
offsprings are identical, so should survive well in the conditions in which parents grow
Disadvantages of asexual reproduction (2)
Lack of variation means that any adverse change in conditions will affect all
offsprings do not vary so they are not suited to moving away and exploiting environments with different conditions
What is a gamete
sex cell
Define sexual reproduction
process involving the fusion of the nuclei of two gametes (sex cells) to form a zygote and the production of offsprings that are genetically different from each other
is gamete haploid or diploid
haploid
Is zygote haploid or diploid
diploid
Advantages of sexual reproduction
Variety in offsprings
- produce individuals that may be better adpated to different conditions, increasing chance of survival of species
Disadvantages of sexual reproduction (2)
requires second parent for fertilisation
The need to find a mate means that sexual reproduction takes longer to produce offspring than asexual
What is fertilisation
nucelus of a male gamete fuses with the nucelus of a female gamete to form a zygote
The functions of the key parts of an insect-pollinated flower (5)
sepal - help to protect the growing flower and stop it from drying out
petal - brightly coloured to attract insects and animals to pollinate the plant
Anther - produces plant gametes (pollen)
Stigma - covered in a sticky, waxy layer that traps the pollen of other plants.
Ovary - contains an ovule (a gamete)
What are the male parts of a flower called and what do they contain
Collevtively called Stamen
contains an anther and filament
What are the female parts of a flower called and what do they contain
Collectively called Carpel
contains the stigma, style, and the ovary
Define pollination
transfer of pollen grains from the anther to the stigma
Features of wind - pollinated plants (9)
Small petal - to not obstruct pollen dispersal
inconspicuous petals
no scent
no nectaries
many anthers which are often large and hang outside the flower so that pollen is easily dispersed
pollen grains have smooth outer walls
stigmas are large and feathery, often hang outside the flower to trap pollen
produce large amounts of pollen
pollen is lightweight
Features of insect - pollinated plants (9)
large petals for insects to land on
brightly coloured petals to attract insects
often scented to attract insects
nectaries present at the base of the flower produce a sugary liquid to attract insects
a few small anthers, usually held inside the flower
pollen grains have sticky or spiky outer walls
stigmas are small and held inside the flower
produce smaller amounts of pollen
pollen is heavier
When does fertilisation in plants occur
when a pollen nucleus fuses with a nucleus in an ovule
Define germination
when the seed coat breaks open and the embryo starts to grow and develop into a new plant
What are the 3 environmental conditions needed for successful germination (3)
Temperature
Water - Swell seed and burst seed coat
Oxygen - respiration
What is more water needed for during germination (4)
Activation of hormones an enzymes
hydrolysis of storage compounds, eg: conversion of starch to glucose
Transport of materials to be used for respiration and growth
Metabolic reactions and enzyme actions that occur in solution
Where is sperm produced
tesetes
Why are the testes supported outside the body in the scrotum (2)
Keep tests cool
at high temperatures, fewer sperm are produced
Purpose of sperm duct
carry sperm from the testes to the penis
Purpose of prostate gland and seminal vesicles
produce liquid called semen
