Topic 4 - Biodiversity + natural resources Flashcards
(95 cards)
1
Q
Species
A
a group of organisms with similar morphology, physiology and behaviour, which can be interbred to produce fertile offspring.
2
Q
Binomial classification
A
Two part Latin name given to species:
first part: genus
second part: species
3
Q
hybrid
A
animals made by breeding two animals together of the same genus but not species
4
Q
habitat
A
the place where an organism lives
each habitat has a particular set of conditions that supports a distinctive combo of organisms
5
Q
population
A
interbreeding group of the same species found in an area
6
Q
community
A
various populations in a habitat
7
Q
Niche
A
the way an organism interacts with/exploits its environment
8
Q
Adaptation
A
features that enable organisms to survive.
adaptations can be classed as behavioural, physiological or anatomical
9
Q
behavioural adaptations
A
actions carried out by the organism helping it survive/reproduce
10
Q
physiological adaptations
A
the features of the internal workings of an organism that helps it survive/reproduce
11
Q
anatomical adaptations
A
structures we can see when we observe/dissect an organism
12
Q
co-adaptation
A
when plants and insects evolve in tandem and become dependent on each other and more closely adapted
13
Q
stages of natural selection
A
- Variation within species (mutations)
- Change in environment (selection pressure creates competition)
- Survival of the fittest (those best adapted survive)
- Better adapted reproduce and pass on alleles to offspring, the allele that is favourable will become more common
Natural selection results in organisms well adapted to particular niche.
14
Q
evolution
A
the change in in allele frequency of a population over time (generations)
15
Q
selection pressure
A
change in the environment give some organisms an advantage and others a disadvantage
16
Q
gene pool
A
all the alleles of all the genes in a population
variation must exist in a gene pool for evolution to occur
17
Q
mutation
A
Changes in DNA sequence
they are likely to accumulate in gene pools of large populations, each mutation creates a new allele
18
Q
advantageous change
A
individual is more likely to survive and reproduce - allele frequency in population will increase
19
Q
disadvantageous change
A
natural selection will remove it from the gene pool
20
Q
neutral change
A
no change in chances of survival, remains in the gene pool by change
21
Q
genotype
A
genes you inherit, all the genes an organism has
22
Q
phenotype
A
affected by genotype and the environment, the physical characteristics observed
23
Q
the alleles of a population will remain constant if..
A
- There are no mutations so no new alleles are created
- There is no immigration/emigration so no alleles are introduced/lost
- There is no selection, no alleles are favoured/eliminated
- Mating is random so alleles are randomly mixed
- The population is larger so there are no genetic bottlenecks
24
Q
ability of a population to adapt depends on…
A
- Strength of selection pressure
- Size of gene pool
- The reproductive rate of an organism
25
For a new species to arise..
there must be reproductive isolation of a group of individuals from the rest of the population, with each individual accumulating different gene frequencies
26
speciation
formation of a new species
| once two populations aren't able to breed and produce fertile offspring, they are considered to be two different species
27
biodiversity
measure of the variety of living organisms and their genetic differences - diversity within animals
28
genetic diversity
measure of genetic variation found in a particular species
29
Measuring diversity
1. Counting different alleles in a population
2. Heterozygosity
Both measures calculated as an average over a number of loci
30
gene point mutations
alterations of gene base sequence
31
chromosome mutation
sections of chromosome rearranged during meiosis
32
independent assortment
is homozygous pair of chromosomes is assorted independently from others during meiosis
33
crossing-over
Genetic material exchanged between homologous pairs during meiosis resulting in new combo of alleles.
34
measuring genetic diversity in a species by looking at heterozygosity
Genetic diversity can be measured by DNA sequences
DNA can be cut into fragments then separated using gel electrophoresis
Heterozygous and homozygous can be identified because of the fragments they produce at different lengths
35
species richness
simplest way is to count number of species present in a habitat.
36
species evenness
takes into account population size of species – a community in which most of the species have a similar abundance are said to have high evenness, no single species dominates the community
37
endemic species
species found in one particular region and nowhere in the world.
38
Biodiversity hotspot
areas of unusually high biodiversity
39
Hierarchy of grouping
```
Kingdom
Phylum
Class
Order
Family
Genus
Species
```
40
classification
arrangement of organisms into groups of various sized based on their shared features.
41
Taxonomy
form of classification focusing on physical similarities between different species for ease of naming and classification.
42
phylogeny
classification of organisms by their evolutionary relationships, so every group shares a common ancestor.
43
Animalia
Multicellular eukaryotes that are heterotrophs (organisms that obtain energy by ingesting material from other organisms.
44
Plantae
Multicellular eukaryotes that are autotrophs (organisms that make their own organic material by photosynthesis.
45
Fungi
Multicellular eukaryotic heterotrophs that absorb nutrients from decomposing matter after external digestion.
46
protoctista
Esingle celled eukaryotes that feed on organic matter from other sources like algae.
47
prokaryotae
Unicellular organisms like bacteria.
48
3 plant principals to grow tall
They produce strong cell walls out of cellulose, a polymer made of sugar molecules
They build columns and tubes from specialised cells
They stiffen some of these special cells with another polymer called lignin
49
What only plants have
Rigid cell wall -> outside cell membrane
Chloroplast -> site photosynthesis
Amyloplast -> contains starch grains
Central vacuole -> bounded by membrane (tonoplast)
50
Cell wall composition
Number of polysaccharides like cellulose
Thin layer called middle lamella (made of protein) marks the boundry between adjacent cell walls and cements adjacent cell walls together.
51
Crossing the cell wall
Cell walls don’t separate completely
Narrow fluid channels that cross cell walls make cytoplasm of one cell connect to the next
Cell wall is thin in some places as first layer of cellulose is deposited - results in pit in cell wall
Plasmodesmata aids movement of substances between cells
Plasmodesmata are often located in these pits
52
chloroplast
conducts photosynthesis, traps energy from the sun, contains chlorophyll (green pigment)
53
Amyloplast
Organelle that synthesises + stores starch granule, contains starch grains (composed of a-glucoses), responsible for conversion of starch into sugar
54
Vacuole
Regulates internal environment, sac full of water that helps maintain cells shape, stores nutrients + waste products
55
Tonoplast
Vacuolar membrane, Separates vacuole contents from cytoplasm
56
cell wall
protective, semi-permeable outer layer of plant cell – mainly made of cellulose (composed of β-glucoses), Gives cell strength + structure. filters molecules passing in/out of cells
57
cell surface membrane
phospholipid bilayer containing proteins forming a partially permeable membrane, protects cell from its surroundings
58
nucleolus
dense body within nucleus, composed of proteins and nucleic acid, produces ribosomes
59
chromatin
consists of small proteins (histones) and DNA. Composed of DNA that condenses to form chromosomes – located in nucleus, Compresses DNA so it can fit into the nucleus
60
Golgi apparatus
Stacks of flattened membrane – bound sacs formed by fusion of vesicles from the ER, Modifies proteins + packages them in vesicles for transport
61
Rough endoplasmic reticulum
vast interconnected membrane system located close to nucleus, ribosomes are attached to its outer surface, Transports proteins made on ER to other parts of the cell
62
Smooth endoplasmic reticulum
like rough er but has no ribosomes attached to it, Makes + transports lipids and steroids
63
Cellulose
A plant’s strength partly comes from cellulose, is it a polysaccharide – polymer of glucose
A condensation reaction between the –OH of the first carbon of one glucose and –OH from another adjacent glucose molecule links them together.
1.4 glycosidic bond forms
Due to this cellulose is a long unbranched molecules
64
Microfibrils
bundles of cellulose, arranged in layers in the cell wall.
| Formed between -OH of neighbouring cellulose molecules
65
Xylem vessels
These form tubes for transport of water + minerals, their stiffened cell wall helps support the plant.
66
sclerenchyma fibres
Column of fibres providing support for xylem + phloem within their stiffened cell walls. Impregnated with lignin.
67
phloem sleeve tubes
Long tubes for transport of organic solutes like sugars + amino acids. They have no role in providing plant strength.
68
epidermis tissue
Single layer of cells covering entire outer surface of plant.
69
vascular tissue
Involved in transport surrounded by ground tissue.
70
ground tissue
Contains cells specialised for photosynthesis, storage and support.
Bulk of plant consisting of parenchyma tissue, collenchyma tissue and sclerenchyma tissue.
71
xylem vessel formation
lignin impregnates cellulose cell wall, lignifying cell walls and restricting entry of water.
At the same time coroplast breaks down and there’s autolysis of cell’s contents.
During autolysis, cell organelles, cytoplasm and cell surface membrane are broken down and lost, leaving dead empty cells that form a tube.
72
Cohesion theory
Water molecules are polar and form hydrogen bonds – this is cohesion.
Forces of attraction between polar water molecules and polar groups in cell walls of xylem mean water can stick to walls of xylem, known adhesion.
Water is pulled up the xylem by tension generated by transpiration, aided by cohesion and adhesion of water molecules.
Xylem must be a continuous column of water for this to work, eg no bubbles.
73
phloem sleeve tubes
Smaller tubes that carry sucrose solution and amino acids from leaves (photosynthesis) or storage organs to the rest of the plant (flow is bidirectional).
Phloem sleeve tubes are living cells joined end to end, with pore-filled sleeve plates between them.
74
how are phloem sleeve tubes adapted to their function
Cell walls + cell surface membrane has small infoldings, increasing surface area.
They also contain many plasmodesmata, linking their cytoplasm to the adjacent cells.
Packed with mitochondria providing energy for loading solutes into the sleeve tube.
75
how to bacteria reproduce
Bacteria produce asexually (binary fission). The cellular DNA replicates and new cell content is synthesised before new cell wall forms to divide the cell into 2 rough halves.
76
Bacteria growth stages
Lag phase: cells are adjusting to the conditions.
Exponential phase: cells are diving exponentially at fastest rate possible for conditions.
Stationary phase: growth limited by eg lack of food, buildup of waste or pH.
Death phase: number of cell deaths is greater than cells formed.
77
conditions for bacteria growth
Sufficient nutrients
Optimum pH + temp
No build up of waste
Sufficient Oxygen
78
Pre-clinical testing
Animal and lab studies on isolated cells and tissue cultures assess safety and determine effectiveness of compound against disease. Tests can take many years, only a handful of chemicals are approved for clinical trials on humans. Animal trials form basis of application for clinical trials on humans authorised by MMRA,
79
clinical trails -phase 1
Volunteers told about drug and are given different doses; volunteers are usually healthy. Trail confirms if drug is being absorbed, distributed, metabolised and excreted as predicted. Effects of different doses are monitored.
80
Clinical trails - phase 2
Small group of volunteers with disease are treated to look at drug effectiveness, if results are promising phase 3 is set up.
81
Clinical trails - phase 3
Large group of volunteer patients with disease are split into two groups, one group is given the compound for the disease and the other is given a placebo – if an existing treatment exists it is given instead of the placebo. It is a double-blind controlled procedure where neither the patient nor the doctor knows who gets what - increases validity.
If stats show significant improvement in patients receiving the treatment compared to the placebo, the compound is effective. Compound can be licensed as a drug for marketing
82
After seed dormancy breaks
When dormancy breaks, seed takes in water from small pore in seed coat.
Absorbing water triggers metabolic changes in seed. Enzymes are produced that metabolise stored food reserves.
Maltase and Amylase break down starch into glucose which is converted into sucrose for transport to the radicle and plumule.
Proteases catalyse proteins in the food store into amino acids. Lipase breaks up lipids in to fatty acids and glycerol
83
seed wind dispersal
traits like wings and feathery styles make seeds and fruit easily wind-borne.
84
Seed water dispersal
seeds and fruits develop floating devices like spongey or fibrous outer coat
85
Seed animal dispersal
seeds and fruit possess hooks, bristles and barb allowing them to attach to animal bodies.
86
seed self-explosive dispersal
Some plants disperse their own seeds. Pods dry and split open suddenly which throws them over great distances.
87
Reasons for extinction
Habitat destruction: deforestation, pollution or climate change.
Overkill: poaching, overfishing, harvesting.
Introduced species: competitors, predators, diseases or parasites.
Chains of extinction: trophic cascade causes species to be affected by another extinct species.
88
Function of zoos
Captive breeding programs
Manage reintroduction programs
Scientific research
Education
89
Captive breeding program purpose
- Increase numbers of species if numbers are very low
- Maintain genetic diversity within the captive population (heterozygosity)
- Reintroduce animals into the wild if possible
- Stud books help track what animals are in each zoo
- Enables survival of species that may otherwise become extinct in the wild
90
Problems with interbreeding
Diseases passed on easily
Increased risk of extinction
Reduces genetic diversity
Passing on harmful alleles increased risk of deformations
Reduces gene pool which leads to extinction
91
genetic shift
The change in allele frequency over time leads to loss of variation – process is by chance.
92
interbreeding depression
In small population the likelihood of interbreeding increases.
This causes an increase in homozygous genotypes and a decrease in heterozygous genotypes.
Frequent mating between related individuals carrying harmful recessive alleles increases, reducing fitness of offspring, narrowing the gene pool.
93
How to manage interbreeding depression
Introducing alleles from a different population can reverse interbreeding depression by increasing heterozygosity.
Species have to be genetically close enough to mate.
94
Advantages of conserving seeds
- Conserves genetic diversity
- Seeds are protected from natural disaster, climate change and economic factors
- Seeds that are resistant to disease, pests and drought can be stored for future medicinal use
- Ensures future food security
95
Why conserve seeds instead of conserving them
Seeds are in controlled conditions
They are protected from environmental factors
Conserves land needed to grow crops
It is more economical
Different plants need different conditions to grow, whereas the seeds can all be stored under the same conditions.
