Name: _____________________ 6.2 - Sexual Reproduction Date: _____________Objectives: By the end of the lesson you should be able to:• Describe the 4 conditions necessary for embryonic development• Compare and contrast internal vs external fertilization• Describe the process of plant pollination

Sexual Reproduction Overview

• Requires a male gamete (_______________) to fertilize the

female gamete (__________)

• The first cell that forms is called a ____________________

• The zygote grows (by _______________) into an

_____________________

Sexual Reproduction

Sexual reproduction brings non-identical gametes together to

form a new organism - it occurs in 3 stages:

• ________________ - the process by which gametes are brought together at same place and same time

• ______________________ - process by which egg and sperm join to form a new organism (zygote)

• ______________________________ - the process by which an organism develops as an embryo

Embryonic Development Requirements

• Enough _________________________

• Temperature must be __________________ enough so proteins and enzymes will function properly

• Sufficient _________________________ so embryo doesn’t dry out

• ________________________ from predators and environmental factors (ex. ____________________)

Types of Fertilization

• ___________________________: egg and sperm meet outside the bodies of the parents

• ___________________________: egg and sperm meet inside the body of the female

External Fertilization

• Common in _______________________________ animals (i.e. salmon, sea urchins)

Advantages:

• Very little _________________________ required

• __________________ number of offspring are produced

• Little ________________________ for food because so spread out

Problems:

• Not all eggs get ____________________________

• __________________________ hazards (ex. Storms)

• Eggs are eaten by ________________________

• Few survive to adulthood

Internal Fertilization

• Common in ______________________ animals (ex. Whales, humans)

• _______________________ sperm can be deposited, only __________ will reach

the egg and only ___________ will fertilize it

• After the egg has been fertilized it changes its _____________________ charge

which prevents any other sperm from entering the egg

Advantages:

• Embryo is ______________________ from predators inside the womb

• __________________________ are typically protected for months or years after birth

Disadvantages:

• Requires ___________________ energy

• Produce _________________ offspring

• Requires ________________ time

Pollination: is the transfer of the male gametes (____________________) to the female gametes (_______)

1. _________________________ produces pollen

2. Pollen lands on ________________________

3. Pollen tube grows down to _____________________

4. Sperm is delivered to egg

5. Fertilization occurs

6. Zygote grows into _____________ which is protected and nourished by _____________

Pollen Transport

• _____________________________ are attracted by coloured _________________ (ex. Bees,

butterflies, bats)

• ___________________________, _____________________________

Seed Transport

_________________________ and ____________________________

Embryonic Development

Embryonic development is the early development of an organism -

in humans, it is the first two months after fertilization

Stages

• End of the first week - ball of cells called

_____________________________

• By end of second week it is a hollow ball called a _________________________

• Cells at this stage are stem cells, and have the ability to develop into any kind of

cell

• 3-4 weeks embryo is known as a ___________________________________

• develops 3 layers:

• _______________ (skin, nerves), ______________________ (muscles, bones), and

__________________________ (lungs, liver, digestive system lining)

Fetal Development - The cell layers now differentiate into the organs and tissues of a baby - this is divided

into 3 trimesters.

• First Trimester (0-12 weeks): ____________________________________ begin to develop and

form. Bone cells form.

• Second Trimester (12-24 weeks): Rapid ______________________ from 12-16 weeks.

• Third Trimester (24+ weeks): Continued growth, especially of _______________________. Fat

begins to deposit at 32 weeks to keep baby warm at birth.

Sexual Reproduction Advantages and Disadvantages