Reproduction, Genetics and Evolution
1. Reproduction
1.1. Sexual reproduction is the production of an offspring from two parents.
1.1.1.Combining of gametes (sex cells) is called fertilization in animals and pollination in plants.
When plants grow from a seed we call this germination.
1.1.2.Offspring receives ½ of its DNA from mother and ½ from father.
1.1.3.Meiosis is the process of producing gametes with exactly ½ the chromosomes as normal
cells.
1.1.4.Advantages of sexual reproduction: High survival rate and more variation in species.
1.1.4.1.
Variation is important because it makes the species as a whole better able to
survive changes to the environment and disease.
1.1.5.Disadvantages of sexual reproduction: Slow process that requires lots of energy.
1.2. Mitosis can be used as a form of asexual reproduction in single celled organisms and also as
growth and development of cells in multicellular organisms.
1.3. Asexual reproduction is the production of an offspring from only one parent. The offspring is
almost always an exact copy of the parent.
1.3.1.Methods of asexual reproduction: Budding, Mitosis, and spore formation.
1.3.2.Advantages of asexual reproduction: Very fast and requires low amounts of energy.
1.3.3.Disadvantages of asexual reproduction: Low survival rate and susceptible to changes in
environment and disease.
2. Heredity
2.1. Heredity is the passing of traits from one generation to the next.
2.2. Heredity can be predicted by studying DNA which form genes on chromosomes in the nucleus
of cells.
2.3. Complete the Punnett Square problem on the board.
3. Change over time
3.1. Change over time is also known as evolution. It describes how and why species on Earth have
changed over time.
3.1.1.Natural Selection is the motor that most scientists believe driving evolution. Natural
selection is pressures within the environment favor the survival of the fittest (strongest,
smartest, etc.).
3.1.1.1.
Example of Natural selection: A species of moths can be black or white, most of
the species are white because they blend in with their environment better. A
volcano erupts and covers most things in black soot, now the black moths are better
camouflaged and live better. Over time the population will change to where most of
the population are black and not white.
3.1.2.Speciation is where natural selection occurs to a point where two or more groups of the
population become so different they become different species. This is a long gradual
process.
3.1.2.1.
Example of speciation due to natural selection can be seen in the finches Darwin
found on the Galapagos Islands. Read pages 142-143 and write a summary.
3.1.3.Other factors that lead to speciation: Other than natural selection, the biggest factor that
leads to speciation is geographic isolation. This is where a species gets separated by some
large geographic feature that makes it impossible for them to breed any longer. Over long
periods of time differences will build up in these separated populations and they will
eventually be two different species.
3.1.4.Fossil record is the largest piece of evidence that supports change over time in organisms.
Studying the fossils it is clear that organisms have changed over time.
3.1.4.1.
Know how to read an evolution diagram like the one on page 145.
4. Adaptations and Extinctions
4.1. Adaptations occur when an organism is introduced into a new environment or an environment
changes.
4.1.1.Individual organisms can develop beneficial adaptations. This allows that organism more
chance to reproduce and pass on those beneficial adaptations. Over time this adaptation
will become more and more prevalent in the population and that is change over time or
evolution.
4.2. Extinctions occur when organisms are faced with pressures that they can’t handle or adapt to.
5. Geologic Timescale
5.1. Know how to read a geologic timescale like the one that can be found on page 148.