Wild Flower Flashcards
When did the first fossil flowers appear?
Mid-Cretaceous (100Ma)
Archaefructus (early fossil flower)
-125Ma
-Chinese fossil
-Aquatic
-No petals
-Dioecious
Montsechia (early fossil flower)
-130Ma
-Aquatic
-Found in Spain
What were the Angiosperms innovations?
-Double fertilisation
-Vessels
-Ovary encasing the seed
-Monoecious
What vessel structure do the Gymnosperms have?
Tracheid’s: narrow hollow cells with overlapping ends. (less prone to embolisms)
What vessel structure do the Angiosperms have?
Xylem: Wider vessels with better contact between the cells resulting in more efficient water flow. (more prone to embolisms)
What is a cased seed?
A seed protected by the ovary which is formed from maternal tissues.
Endosperm
storage tissue that feeds the embryo (also exhibited by gymnosperms)
Describe Double Fertilisation.
Double fertilization is a unique process that occurs in flowering plants (angiosperms). This process involves the fusion of two sperm cells with different cells within the ovule, leading to the formation of both the embryo and the endosperm.
Amborella Trichopoda
-no vessels only tracheid’s
-the first flowers
-the most basal angiosperm
-Dioecious (separate male+female parts)
-females have staminodes (infertile stamens)
Describe the process of pollination within the Gymnosperms.
-Male and female cones
-Pollen spread by the wind therefore more pollen needed (uncontrolled)
-Pollen stolen by insects
Describe the process of pollination within the Angiosperms.
-Male and female organs brought together
-Pollen carried by insects to the female organ
-increased risk of self pollination and hybridisation
What is specialisation?
The co-evolution of plants and animals resulting in special relationships which increases diversity in both groups
Give some examples of specialised relationships.
-Darwin’s orchid-very long nectary=moth with long mouth
-Orpheum Frutescens-twisted and locked stamens=only accessible by the carpenter bee when wings vibrated at a specific frequency
-Fruit-designed to be eaten and passed through the gut=spreads the seed
What is a herb?
-A plant with soft tissues only
-No secondary thickening
-May die down in winter
-No extant Gymnosperm herbs
What are the pros and cons of producing wood?
Pros:
-Can grow tall
-Competition for light
-Resilient
Cons:
-Expensive
-Inflexible
What are Ephemerals?
Weed species that live fast and die young. They are usually annual plants and exploit transient gaps in ecosystems.
What occurred within phytoplankton to produce the wide variety seen today?
Endosymbiosis of the 3 main algae occurred in multiple stages resulting a large variety of new algae.
Dinoflagellates.
-Appeared in Triassic
-May have a cellulose cell wall
-May be hetro, auto or mixotrophic
-May be from secondary or tertiary endosymbiosis
-Usually formed from rhodophytes but contain no Phycobillosomes
-Contains chlorophyll A+C and carotenoids
Coccolithophores.
-Haptophyta (group)
-Upper Triassic
-Probably Rhodophytes
-Brown chloroplasts- A+C and fucoxanthin
-Calcium carbonate shell
-Emits dimethyl sulphide=seeds cloud formation
Diatoms.
-Jurassic
-Non motile
-Silica shell
-4 chloroplast membranes
-Heterokonta (group)
-Rhodophytes
-Chlorophyll A and Fucoxanthin
Describe the impact of plate tectonics on phytoplankton.
High levels of tectonic activity results in calcite seas (low in MgCa(CO3)2) whereas low tectonic activity results in Aragonite seas (high MgCa(CO3)2) this changes which algae’s dominate.
Foraminifera.
-Marine protists
-many form CaCo3 shells
-elaborate structures
-can be used to age rocks
What percentage of global carbon fixation is due to algae?
Approx. 50%
Why are phytoplankton important?
-They form the basin of all marine food webs.
-They are a major driver of the ocean carbon cycle.
