Continuation of Species
Life Science Unit 3 Lesson 11
Attendance link: http://goo.gl/forms/AixZf2IXz9
Expectations
• Required Class Connects
• Tuesday, Wednesday, & Thursday
• 1:30-2:30 pm
• Be active and participate in class.
• Be respectful to your classmates
• Be positive in the chat box and use it correctly.
• Have a working microphone!
• You will need it during the lessons and break out rooms.
• If you have a question, please place it in the chat box and repost it if
I don’t see it.
Objectives
• Recognize that reproduction is essential for the
continuation of a species.
• Describe the life cycle of asexual organisms.
• Explain how asexual organisms reproduce.
• Compare biological advantages and disadvantages
of asexual and sexual reproduction.
For a species to continue to exist what must
happen?
• The species must make others like
themselves.
• How is this done?
• Through reproduction.
What is reproduction?
• Reproduction is the process by which living
things make other living things identical or
similar to themselves.
• Parents create offspring(s)
• Parents pass their genetic information to the
offspring.
• This helps to maintain a species’ beneficial
characteristics through many generations.
Types of reproduction
• Asexual reproduction
• A single organism produces a new,
identical organism.
• There is only one parent so the
offspring is 100% identical to the
parent (not counting mutations).
• This can be through the parent
dividing, creating a bud, or the
like.
• There is a fish that only has
females and some trees create new
one ones via new shoots from the
roots.
Think it through…
Aspen trees reproduce asexually by offshoots of their roots. This
produces a group of identical aspen trees. Suppose a new
disease attaches one of the trees and kills it. Describe what is
likely to happen to other aspen trees in the groups and explain
why?
The other aspen trees will probably die off because they are
genetically identical to the parent, which was unable to fight the
disease that killed it. This is an example of one disadvantage of
asexual reproduction.
Types of reproduction
• Sexual reproduction
• The process in which two sex cells join together to
form a new organism.
• 50% of the offspring’s DNA comes from each parent.
• Fertilization can happen inside or outside of the
parent.
Which of the following statements is true of
offspring from organisms that reproduce asexually?
A.Offspring are genetically identical to the
parent
B.Offspring are genetically different from the
parent
C.Offspring have not features like the parent
D.Offspring have some features like the parent
Compare the two
Asexual
• Grow in number at a faster rate.
• Takes less time and energy for a
single cell to divide in half or for a
new bud to form.
• Offspring are genetically identical
to the parent.
• Genetic variation is low in offspring
produced asexually.
• Both genetic strengths and
weaknesses are passed from parent
to offspring.
Sexual
• Grow at a slower rate.
• Takes longer for sperm and egg to combine
and develop into a new individual.
• Genetic information from two parents is
combined in the offspring.
• Genetic variation is higher in offspring
produced by sexual reproduction.
• Genetic variation increases the likelihood
that at least some of the offspring will
inherit characteristics that make them
better suited for survival.
What would happen if fertilization no longer
occurred in a species that reproduces sexually?
A. The species would increase in number
B. The species would decrease in number and
eventually die off.
C. Individual variation within the species would
increase.
D. Disease would destroy the species.
How does an adult hydra produce a new
hydra?
A.By developing a seed
B.By making a spore
C.By growing a bud
D.By splitting itself into two equal parts
Compare the two
Asexual Reproduction
Sexual reproduction
Genetic Variation
(low or high)
Low
high
# of parents
(one or two)
One
two
Sex cells involved?
(yes or no)
No
yes
Examples:
Hydra, flatworm, some plants
mammals, most animals
What is one advantage of sexual reproduction
over asexual reproduction?
Genetic variation increases with
sexual reproduction.
Specific
genetic
weaknesses,
such
as
susceptibility to a certain disease,
are not necessarily continued in
offspring.
What is the name of the process in which an
organism makes a new organism?
A.Mutation
B.Fertilization
C.Variation
D.Reproduction
Assignment
• OLS
• Part 1 – 4 Questions
• Part 2 – 2 Questions
• Make sure that you have ALL of your
OLS lessons mastered.