Download Unit 1: Biological Diversity

Unit 1: Biological Diversity
1. Observe variation in living things.
 Look out the window
 Observe members of the class
 Biological Diversity (biodiversity) – number and variety of organisms (in an
ecosystem, on the planet)
 Diversity Index – used to measure/monitor the health of an ecosystem.
 Variation – differences in characteristics
2. Describe examples of variation:
- among species;
- within species.
 Species – one type of organism
- interbreed in nature
- offspring are able to breed
 Species differ from each other – e.g. birds (crows, sparrows, Galapagos Finches),
snakes (rattlesnake, anaconda), etc.
 Speciation – evolution of new species from a common ancestor
 Members of a single species show variation - e.g. people – height, weight, skin
colour, intelligence, etc.
 Activity – page 9
3. Identify examples of niches.
 Niche – where an organism lives and what it does (what role it plays)
 Examples
- cougars and lynx
- owls and hawks
- warblers
 Broad niche – species are said to be generalists, able to survive in ecosystems where
climate and food sources are variable (e.g. Canadian north). Such areas usually have
few species but large populations of each species. Examples – caribou, hare
 Narrow niche – where conditions are more stable (e.g. tropical regions), we find
more species but smaller populations of each species. Organisms tend to be
specialists to compete for one dependable food source.
4. Describe the role of variation in enabling closely related living things to survive in
the same ecosystem.
 Adaptations help an organism to survive, but competition over resources can occur.
One species may gain an advantage over another.
 Organisms alter their niches to avoid or reduce competition, leading to an increase in
variation within or between species.
 Variation enables closely related species to coexist/survive.
5. Investigate and interpret dependencies among species that link the survival of
one species to the survival of others.
 Symbiotic relationship – two organisms that live in direct contact
 Examples (mutualism)
- elk/micro-organisms in rumen
- plants/mycorrhizae on roots
 Other examples ?
6. Identify the role of variation in the survival of species under changing
environmental conditions.
 Adaptations – special structures or behaviours that enable an organism to survive in
its environment
 Members of a species vary in their ability to tolerate changing conditions
(temperature, moisture, food sources). If all were exactly the same, then the entire
species could be wiped out when the environment changes, but some survive and
continue to breed.
7. Distinguish between sexual and asexual reproduction.
 Asexual Reproduction – only one parent supplies the genetic information to create an
offspring
 Sexual Reproduction – two parents supply the genetic information to create an
offspring
8. Describe representative types of asexual reproduction.
 Binary Fission – cell division in one-celled organisms. The cell first duplicates its
genetic content, cytoplasm and other organelles. The cell then divides. Examples:
- amoeba
- bacteria
 Asexual Spores – single-celled reproductive structures produced by some fungi (e.g.
mushrooms) and algae (e.g. chlamydomonas). Only one parent supplies the genetic
material to make the spore.
 Vegetative Reproduction – asexual reproduction from a single plant from rapidly
reproducing meristematic cells in fast-growing tips of roots and stems. Common
example are cuttings that produce new plants. New plants are clones (exact genetic
copies) of the parent. Other examples:
- bulbs (tulips)
- tubers (potatoes)
- runners (spider plant)
 Budding – A cell near the base of the organism produces a new group of cells called
a bud which eventually detaches. Examples:
- hydra
- sea sponge
- yeast
9. Describe representative types of sexual reproduction.
 Zygospores – long strands of cells called hyphae grow out of asexual spores. Where
the tips of the hyphae from two different spores meet, a zygospore, which contains
genetic material from both hyphae, is formed (page 31)
 Bacterial Conjugation – a primitive form of sexual reproduction (figure 1.28). Two
bacteria exchange genetic material with each other. This mixes the genetic
information. Following conjugation, the cells reproduce through binary fission to
form new cells.
 Sexual reproduction in plants (page 33) – A pollen grain from the anther is deposited
(by wind, insects, birds, etc.) on the stigma. The pollen grain grows a pollen tube
that eventually reaches the ovule. A sperm nucleus travels down the pollen tube and
fertilizes the egg, forming a zygote. The zygote undergoes many cell divisions to
form an embryo containing a miniature leaf, stem and root.
 Sexual reproduction in animals (page 35) – gametes from the male and female join
during fertilization to form a zygote. In the early stage, the zygote divides many
times (mitosis) to create the embryo. Fertilization may be internal or external.
10. Describe examples of organisms that show both sexual and asexual
reproduction.
 Plants can reproduce through seeds (sexual) or various forms of vegetative
reproduction
 Some moulds can form spores or zygospores
 Mosses produce asexual spores during one part of their reproductive cycle. In a later
part, egg and sperm cells are produced.
11. Describe the formation of zygote and embryo in plant reproduction.
 See 9 – zygote is created when sperm nucleus fertilizes the egg. Zygote divides
many times to form embryo. Embryo contained inside the seed along with the
cotyledon(s) (figure 1.30)
12. Describe the formation of zygote and embryo in animal reproduction.
 See 9.
13. Describe examples of variation of characteristics within a species and identify
examples of discrete variation and continuous variation.
 Discrete Variation – inherited characteristics which have only a limited number of
possibilities. Examples:
- ability to curl your tongue
- blood type
- mid-digital hair
- earlobe attached/detached
- hairline smooth or pointed
 Continuous Variation – inherited characteristics that can vary over a wide rage of
possibilities. Examples:
- height
- hand span
- weight
- intelligence
14. Investigate the transmission of characteristics from parents to offspring and
identify examples of characteristics in offspring that are:
- the same as the characteristics of both parents;
- the same as the characteristics of one parent;
- intermediate between parent characteristics;
- different from both parents.
 Activity 1-F, page 41
15. Distinguish characteristics that are heritable from those that are not heritable.
 Heritable – characteristics that are genetically controlled and passed on in the genetic
material from parent to offspring. Examples:
- eye colour
- hair colour
- height
 Some inherited characteristics are dominant, others are recessive (page 40)
- dominant – a characteristic that appears if either parent has it
- recessive – a characteristic that appears only if both parents have it
 Non-heritable – other characteristics that are not passed on but are acquired by an
individual after birth. Examples:
- scars
- fitness
- others?
16. Identify characteristics for which heredity and environment may both play a
role. (page 42)
 Weight – both genetics as well as lifestyle
 Musical ability – natural aptitude (inherited) as well as practice and encouragement
(environment)
17. Describe in general terms the relationship between chromosomes, genes and
DNA.
 DNA (deoxyriboenucleic acid) is the basic genetic material inside the nucleus of each
cell
- a long, complex molecule made by joining together a series of nucleotides, like
links in a chain, or rungs on a ladder
 The DNA in a cell is not just one long/huge molecule. It comes in tightly coiled
“packages” or strands called chromosomes
- humans have 46 chromosomes in their cells (somatic)
 The DNA in each chromosome is divided into segments called genes.
- each gene segment contains a unique sequence of nucleotides
- this “code” is used to build a specific protein
- proteins are used to build cell structures also control cell/body functions
18. Interpret the role of DNA, chromosomes and genes as repositories of genetic
information. (page 46 – 49)
 The kinds of proteins a cell makes determines everything about the organism – size,
shape, characteristics, etc.
 The kinds of proteins made by a cell are determined by the “genetic code” – the
nucleotide sequence along the length of the DNA molecule in each chromosome
 The DNA molecule in each chromosome is copied during reproduction so that the
genetic information is passed on to new cells
19. Distinguish between cell division that leads to identical daughter cells, as in
binary fission and mitosis, and cell division that leads to formation of sex cells, as in
meiosis.
 Binary fission – division of a single-celled organism into two organisms
- e.g. bacteria
- new cell gets a complete copy of the genetic material from the original cell
 Mitosis (page 50) – division (splitting, reproduction) of somatic cells in a multicelled organism
- e.g. growing new skin cells to replace ones that die
- all 46 chromosomes are copied into the new cell
 Meiosis (page 51) – splitting of a single somatic cell into 4 “sex cells” (gametes)
- starts with copying of all the chromosomes
- two cell divisions occur so that each gamete carries only 23 chromosomes
- process is random – each gamete will get a combination of paternal and maternal
chromosomes
 IB Curriculum goes into more detail
20. Describe in general terms the synthesis of genetic materials that takes place
during fertilization.
 A sex cell from the male (sperm) joins with the sex cell from a female (egg) to form a
zygote
- sperm cell has 23 chromosomes
- egg cell has 23 chromosomes
 Zygote now contains 46 chromosomes (23 from father, 23 from mother)
21. Compare sexual and asexual reproduction in terms of the advantages and
disadvantages.
Asexual Reproduction
Sexual Reproduction
Advantages
Requires only one parent
Quicker
Less energy
More offspring
More variation
Increased survivability
under changing
environmental
conditions
Disadvantages
Makes clones – less
variation
Leads to risks when
environment changes
(e.g. banana)
Requires more energy
Fewer offspring
22. Distinguish between and identify examples of natural and artificial selection.
 Natural Selection (p64) – naturally occurring process where only organisms with the
best traits for survival in an environment tend to reproduce. Survival of the fittest.
Leads to changes in genetic characteristics of a species over time.
- organisms produce more offspring than can survive
- lots of variation
- some of these variations increase the chances of survival and reproduction
- these characteristics are passed on, others are lost, leading to changes in genetic
characteristics of the species (evolution)
- e.g. peppered moth, horse evolution
 Artificial Selection (Selective Breeding) p58 – human intervention in breeding by
allowing only organisms (plant/animals) with specific desired characteristics to
breed. Not genetic engineering. Still a natural process. Used extensively in
agriculture – relatively few breeds/strains used (e.g. purebred dogs, beef cattle, milk
cattle, sheep, pigs, wheat – amber durum, red spring, rice)
23. Describe in simple terms some of the newly emerging technologies for
recombining genetic material.
 Genetic Engineering – altering the genes in an organism to obtain desired traits
- also called Biotechnology
 Transgenic animals – putting genes from one species into another species
 Example: putting the human gene responsible for production of insulin into bacteria
- bacteria produce insulin as a waste product
- cheaper than harvesting insulin from dead animals
 Example - making complex human proteins (e.g. lactoferrin) by inserting human
genes into cows, sheep, pigs. Mammals better for making complex proteins
 Example – inserting bacterial genes into pigs that degrade phosphates and reduce
environmental effects of manure
 Example – Aquaculture: putting genes into fish for disease resistance, producing
antifreeze or producing growth hormones
 Example – genetically altering food crops to get desired traits (disease resistance,
tolerance to herbicides, earlier/slower ripening, more nutritious, etc.)
24. Identify questions and issues related to the application of emerging genetic
technologies.
 Public concerns about tampering with nature (playing God)
 Accidental release of altered genetic organisms into the environment where they may
cross breed with other organisms with unintended or negative effects.
 Escape of transgenic animals that would compete with natural populations and wipe
them out
 Creation of monocultures – widespread use of only a few varieties of plants and
animals in farming, reducing biodiversity and increasing risks in the food supply
from pests and diseases (e.g., bananas)
25. Describe the relative abundance of species on earth and in different
environments.
 Greatest diversity is in the tropical areas – conditions favourable for many species
(heat, light, rainfall, plant growth to support complex food chains)
- rainforests – most diverse ecosystem on land
- coral reefs – most diverse ecosystem in water
 Diversity goes down as we move towards the poles.
- also depends on local climate/geography
26. Describe ongoing changes in biological diversity through extinction and
extirpation of native species.
 Extinction – species no longer exists on the planet
- e.g. passenger pigeon
 Extirpation – species is wiped out of an area
- e.g. grizzly bear
 5 major declines in earth’s biodiversity in last 600 million years
- probably related to dramatic changes in earth’s climate where conditions changed
too rapidly for species to adapt
- 99% of species in earth’s history no longer exist
 Currently losing species at a rate of 70 per day
- biodiversity is declining
- 6th major extinction underway?
27. Investigate the role of environmental factors in causing changes in biological
diversity.
 Bioindicator species – species (usually larger carnivores, e.g. bear, wolf) that are
tracked to monitor impact of human interference in an ecosystem
 Human impacts believed to be changing the environment
 Disappearing habitats – clearing land (e.g. rainforests) for farming, ranching, logging,
mining, industry, growth of cities to meet population explosion (n.b. developing
countries)
 Introduced species – non-native species compete and extirpate native species
- e.g. loosestrife
- e.g. zebra mussels
- e.g. Suffield horses
 Global climate change – warming of the atmosphere and changing rainfall patterns
 Over-hunting/over-fishing
- e.g. Wooly Mammoth
- e.g. cod and other fish
 Pollution – chemical, thermal
28. Evaluate the success and limitations of various local and global strategies for
minimizing loss of species diversity.
 Zoos – part of an international network to protect/preserve/breed endangered
animals/plants and conduct research. Issues:
- usually handle only larger animals
- inbreeding weakens the species
- more expensive than preserving natural habitats
- how decide which species are saved?
 Seed banks – gather and store seeds from endangered plants and preserve the genetic
material as a future resource. Issues:
- may only collect 10% of the world’s seed-bearing plants
 Global treaties to protect endangered plants and animals to prevent import/export of
endangered species (e.g. ivory) and set up protected areas. Issues:
- poaching still a major problem
- some countries don’t protect much land
- inconsistent rules about land uses in protected areas for recreation, hunting,
forestry, etc.
 Organizations that work to preserve habitat, protect endangered species (e.g.
Greenpeace, Ducks Unlimited). Issues:
- poorly funded
- often at odds with gov’t
29. Investigate and describe the use of biotechnology in environmental, agricultural
or forest management, and investigate potential impacts and issues.
 See 23, 24
 Natural Selection – “strongest” (best adapted) organisms survive and breed (Darwin)
 Selective Breeding – humans intervene to choose the plants/animals with desirable
traits and breed them
- extensively used for centuries
- responsible for most of our main food crops (grains, beef, etc.)
 Issues:
- Creation of monocultures – widespread use of only a few varieties of plants and
animals in farming, reducing biodiversity and increasing risks in the food supply
from pests and diseases (e.g., bananas)
- Inherited weaknesses in purebred strains